ORCID Profile
0000-0002-8203-7223
Current Organisation
UNSW Sydney
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Catalysis and Mechanisms of Reactions | Theoretical and Computational Chemistry not elsewhere classified | Functional Materials | Macromolecular and Materials Chemistry | Condensed Matter Physics | Theory and Design of Materials | Electronic and Magnetic Properties of Condensed Matter; Superconductivity | Degenerate Quantum Gases and Atom Optics | Nanoelectronics
Expanding Knowledge in the Physical Sciences | Commercial Energy Conservation and Efficiency | Management of Greenhouse Gas Emissions from Information and Communication Services | Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in Engineering |
Publisher: Wiley
Date: 07-11-2021
Abstract: Liquid–liquid interfaces of liquid alloys with electrolytic solutions present fertile platforms for realizing exciting interfacial phenomena that can be devised to process alloys and produce nanomaterials. Here, such an interface is established by immersing a gallium–bismuth binary liquid alloy into aqueous electrolytes. It is shown that the application of a negative voltage to this interface results in a rapid and complete liberation of bismuth nanostructures from liquid gallium. The set of conditions that govern the chemistry of the interface can be adjusted to control the oxidation state, morphology, and crystal structure of the expelled bismuth. By changing the conditions nanotubular, atomically thin plates, and sea‐urchin‐shaped bismuth oxide morphologies are obtained. The process can also control the crystal phase of bismuth oxide as monoclinic (α), tetragonal (β), or body‐centered cubic (γ). The addition of ascorbic acid to the electrolyte is observed to prevent the oxidation of the expelled entities, resulting in bismuth metal nanoparticles. Ab initio molecular dynamics and computational fluid dynamics simulations are performed to elucidate this rapid phase separation at the interface. This knowledge will potentially lead to new pathways for using alloys as reaction media to refine metals while simultaneously producing nanomaterials for various applications.
Publisher: Wiley
Date: 16-10-2015
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9FD90011J
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2TC01973F
Abstract: Post-transition metal-based liquid alloys are emerging as media for undertaking chemical reactions.
Publisher: American Chemical Society (ACS)
Date: 31-01-2013
DOI: 10.1021/NN305507P
Abstract: Reduced graphene oxide (rGO) is a promising material for a variety of thin-film optoelectronic applications. Two main barriers to its widespread use are the lack of (1) fabrication protocols leading to tailored functionalization of the graphene sheet with oxygen-containing chemical groups, and (2) understanding of the impact of such functional groups on the stability and on the optical and electronic properties of rGO. We carry out classical molecular dynamics and density functional theory calculations on a large set of realistic rGO structures to decompose the effects of different functional groups on the stability, work function, and photoluminescence. Our calculations indicate the metastable nature of carbonyl-rich rGO and its favorable transformation to hydroxyl-rich rGO at room temperature via carbonyl-to-hydroxyl conversion reactions near carbon vacancies and holes. We demonstrate a significant tunability in the work function of rGO up to 2.5 eV by altering the composition of oxygen-containing functional groups for a fixed oxygen concentration, and of the photoluminescence emission by modulating the fraction of epoxy and carbonyl groups. Taken together, our results guide the application of tailored rGO structures in devices for optoelectronics and renewable energy.
Publisher: American Chemical Society (ACS)
Date: 12-10-2023
Publisher: Springer Science and Business Media LLC
Date: 04-05-2022
DOI: 10.1038/S41467-022-30155-4
Abstract: Platinum is the most efficient catalyst for hydrogen evolution reaction in acidic conditions, but its widespread use has been impeded by scarcity and high cost. Herein, Pt atomic clusters (Pt ACs) containing Pt-O-Pt units were prepared using Co/N co-doped carbon (CoNC) as support. Pt ACs are anchored to single Co atoms on CoNC by forming strong interactions. Pt-ACs/CoNC exhibits only 24 mV overpotential at 10 mA cm −2 and a high mass activity of 28.6 A mg −1 at 50 mV, which is more than 6 times higher than commercial Pt/C with any Pt loadings. Spectroscopic measurements and computational modeling reveal the enhanced hydrogen generation activity attributes to the charge redistribution between Pt and O atoms in Pt-O-Pt units, making Pt atoms the main active sites and O linkers the assistants, thus optimizing the proton adsorption and hydrogen desorption. This work opens an avenue to fabricate noble-metal-based ACs stabilized by single-atom catalysts with desired properties for electrocatalysis.
Publisher: Springer Science and Business Media LLC
Date: 06-06-2022
DOI: 10.1038/S41557-022-00965-6
Abstract: Insights into metal-matrix interactions in atomically dispersed catalytic systems are necessary to exploit the true catalytic activity of isolated metal atoms. Distinct from catalytic atoms spatially separated but immobile in a solid matrix, here we demonstrate that a trace amount of platinum naturally dissolved in liquid gallium can drive a range of catalytic reactions with enhanced kinetics at low temperature (318 to 343 K). Molecular simulations provide evidence that the platinum atoms remain in a liquid state in the gallium matrix without atomic segregation and activate the surrounding gallium atoms for catalysis. When used for electrochemical methanol oxidation, the surface platinum atoms in the gallium-platinum system exhibit an activity of [Formula: see text] three orders of magnitude higher than existing solid platinum catalysts. Such a liquid catalyst system, with a dynamic interface, sets a foundation for future exploration of high-throughput catalysis.
Publisher: Wiley
Date: 30-11-2022
Abstract: MXenes, due to their tailorable chemistry and favourable physical properties, have great promise in electrocatalytic energy conversion reactions. To exploit fully their enormous potential, further advances specific to electrocatalysis revolving around their performance, stability, compositional discovery and synthesis are required. The most recent advances in these aspects are discussed in detail: surface functional and stoichiometric modifications which can improve performance, Pourbaix stability related to their electrocatalytic operating conditions, density functional theory and advances in machine learning for their discovery, and prospects in large scale synthesis and solution processing techniques to produce membrane electrode assemblies and integrated electrodes. This Review provides a perspective that is complemented by new density functional theory calculations which show how these recent advances in MXene material design are paving the way for effective electrocatalysts required for the transition to integrated renewable energy systems.
Publisher: Wiley
Date: 10-07-2022
Abstract: Graphene edges exhibit a highly localized density of states that result in increased reactivity compared to its basal plane. However, exploiting this increased reactivity to anchor and tune the electronic states of single atom catalysts (SACs) remains elusive. To investigate this, a method to anchor Pt SACs with ultra‐low mass loadings at the edges of edge‐rich vertically aligned graphene (as low as 0.71 µg Pt cm –2 ) is developed. Angle‐dependent X‐ray absorption spectroscopy and density‐functional theory calculations reveal that edge‐anchored Pt SACs has a robust coupling with the π‐electrons of graphene. This interaction results in a higher occupancy of the Pt 5d orbital, shifting the d ‐band center toward the Fermi level, improving the adsorption of *H for the hydrogen evolution reaction (HER). Pt primarily coordinated to the graphene edge shows improved alkaline HER performance compared to Pt coordinated in mixed environments (turnover frequencies of 22.6 and 10.9 s –1 at an overpotential of 150 mV, respectively). This work demonstrates an effective route to engineering the coordination environment of Pt SACs by using the graphene edge for enhanced energy conversion reactions.
Publisher: American Chemical Society (ACS)
Date: 21-04-2023
Publisher: MDPI AG
Date: 03-12-2019
DOI: 10.3390/NANO9121725
Abstract: Liquid biopsies use blood or urine as test s les, which are able to be continuously collected in a non-invasive manner. The analysis of cancer-related biomarkers such as circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), microRNA, and exosomes provides important information in early cancer diagnosis, tumor metastasis detection, and postoperative recurrence monitoring assist with clinical diagnosis. However, low concentrations of some tumor markers, such as CTCs, ctDNA, and microRNA, in the blood limit its applications in clinical detection and analysis. Nanomaterials based on graphene oxide have good physicochemical properties and are now widely used in biomedical detection technologies. These materials have properties including good hydrophilicity, mechanical flexibility, electrical conductivity, biocompatibility, and optical performance. Moreover, utilizing graphene oxide as a biosensor interface has effectively improved the sensitivity and specificity of biosensors for cancer detection. In this review, we discuss various cancer detection technologies regarding graphene oxide and discuss the prospects and challenges of this technology.
Publisher: American Chemical Society (ACS)
Date: 06-2022
DOI: 10.26434/CHEMRXIV-2022-WZR8V
Abstract: Electrocatalytic transformations of oxygen, i.e., the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), are key processes in renewable energy conversion, defining to a large extent, the efficiency of numerous energy conversion technologies, such as fuel cells, metal-air batteries or water electrolyzers. However, the development of highly effective, stable and inexpensive materials for such conversion processes is a bottleneck. Hence, establishing generic catalyst design principles by identifying structural features of catalysts that influence their performance would constitute a major step towards the rational engineering of advanced electrocatalysts. In this study, by investigating a series of metal-substituted manganese oxide (spinel), Mn3O4:M (M = Sr, Ca, Mg, Zn, Cu), nanoparticles as a model system, we demonstrate experimentally and rationalized the dependence of the activity of Mn3O4:M for ORR and the oxygen binding strength in Mn3O4:M oxides on the properties of the M substituent, viz. the enthalpy of formation of the binary MO oxide and the Lewis acidity of the M2+ substituent. Incorporation of elements M that have a low enthalpy of formation of MO (i.e., highly exothermic oxides featuring relatively strong M‒O bonding) enhances the oxygen binding strength in Mn3O4:M, which increases its activity in ORR due to the established correlation between ORR activity and the binding energy of *O/*OH/*OOH species on the catalyst surface. Our work provides a new perspective on the design of new compositions for oxygen electrocatalysis relying on the substitution by redox-inactive elements affecting the binding energy of oxygen to the surface of the complex metal oxide catalysts (ORR/OER activity descriptor). We speculate that this concept is general and transferrable to a broad selection of materials and processes involving oxygen adsorption and redox, beyond electrocatalysis.
Publisher: Wiley
Date: 16-03-2023
Abstract: Liquid metals provide new dimensions for controlling and governing of reactions. The concept of freely moving metal solutes in liquid metals can be potentially used for enhancing and tuning interfacial reactions. In this work, zinc (Zn), as the solute metal is shown that, can move to the interface, enriching the interfacial area for the efficient synthesis of highly crystalline and porous zeolitic imidazolate framework‐8 (ZIF‐8). The highest rate of reaction is illustrated, and the best quality ZIF‐8, are obtained when a eutectic liquid metal system of Zn with gallium (Ga), containing 3.6 wt.% of Zn, is implemented. It is computationally shown that a combination of Ga activation and freely moving Zn leads to the highest reaction rate and better coordination with organic linkers. The comparisons with solid s les and non‐eutectic systems of Ga liquid demonstrate the advantages of eutectic mix. The work can be expanded to a variety of future interfacial reactions of zeolite imidazole frameworks for commercial scale up.
Publisher: Wiley
Date: 08-06-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9FD90012H
Publisher: American Chemical Society (ACS)
Date: 02-12-2020
DOI: 10.26434/CHEMRXIV.13311881
Abstract: Magic-sized clusters (MSCs) of semiconductor are typically defined as specific molecular-scale arrangements of atoms that exhibit enhanced stability. They often grow in discrete jumps, creating a series of crystallites, without the appearance of intermediate sizes. However, despite their long history, the mechanism behind their special stability and growth remains poorly understood. This is particularly true considering experiments that have shown discrete evolution of MSCs to sizes well beyond the “cluster” regime and into the size range of colloidal quantum dots. Here, we study the growth of these larger magic-sized CdSe nanocrystals to unravel the underlying growth mechanism. We first introduce a synthetic protocol that yields a series of nine magic-sized nanocrystals of increasing size. By investigating these crystallites, we obtain important clues about the mechanism. We then develop a microscopic model that uses classical nucleation theory to determine kinetic barriers and simulate the growth. We show that magic-sized nanocrystals are consistent with a series of zinc-blende crystallites that grow layer by layer under surface-reaction-limited conditions. They have a tetrahedral shape, which is preserved when a monolayer is added to any of its four identical facets, leading to a series of discrete nanocrystals with special stability. Our analysis also identifies strong similarities with the growth of semiconductor nanoplatelets, which we then exploit to increase further the size range of our magic-sized nanocrystals. Although we focus here on CdSe, these results reveal a fundamental growth mechanism that can provide a different approach to nearly monodisperse nanocrystals.
Publisher: Wiley
Date: 12-01-2023
Abstract: Establishing generic catalyst design principles by identifying structural features of materials that influence their performance will advance the rational engineering of new catalytic materials. In this study, by investigating metal‐substituted manganese oxide (spinel) nanoparticles, Mn 3 O 4 :M (M=Sr, Ca, Mg, Zn, Cu), we rationalize the dependence of the activity of Mn 3 O 4 :M for the electrocatalytic oxygen reduction reaction (ORR) on the enthalpy of formation of the binary MO oxide, Δ f H°(MO), and the Lewis acidity of the M 2+ substituent. Incorporation of elements M with low Δ f H°(MO) enhances the oxygen binding strength in Mn 3 O 4 :M, which affects its activity in ORR due to the established correlation between ORR activity and the binding energy of *O/*OH/*OOH species. Our work provides a perspective on the design of new compositions for oxygen electrocatalysis relying on the rational substitution/doping by redox‐inactive elements.
Publisher: Wiley
Date: 04-05-2020
Publisher: Wiley
Date: 08-07-2022
Abstract: Closing both the carbon and nitrogen loops is a critical venture to support the establishment of the circular, net‐zero carbon economy. Although single atom catalysts (SACs) have gained interest for the electrochemical reduction reactions of both carbon dioxide (CO 2 RR) and nitrate (NO 3 RR), the structure–activity relationship for Cu SAC coordination for these reactions remains unclear and should be explored such that a fundamental understanding is developed. To this end, the role of the Cu coordination structure is investigated in dictating the activity and selectivity for the CO 2 RR and NO 3 RR. In agreement with the density functional theory calculations, it is revealed that Cu‐N 4 sites exhibit higher intrinsic activity toward the CO 2 RR, whilst both Cu‐N 4 and Cu‐N 4− x ‐C x sites are active toward the NO 3 RR. Leveraging these findings, CO 2 RR and NO 3 RR are coupled for the formation of urea on Cu SACs, revealing the importance of *COOH binding as a critical parameter determining the catalytic activity for urea production. To the best of the authors’ knowledge, this is the first report employing SACs for electrochemical urea synthesis from CO 2 RR and NO 3 RR, which achieves a Faradaic efficiency of 28% for urea production with a current density of − 27 mA cm –2 at − 0.9 V versus the reversible hydrogen electrode.
Publisher: American Chemical Society (ACS)
Date: 19-07-2021
Publisher: Wiley
Date: 17-03-2020
Publisher: American Chemical Society (ACS)
Date: 09-02-2022
Publisher: American Chemical Society (ACS)
Date: 17-08-2023
Publisher: American Chemical Society (ACS)
Date: 07-03-2013
DOI: 10.1021/JP309434A
Publisher: American Chemical Society (ACS)
Date: 20-09-2012
DOI: 10.1021/NN302893P
Abstract: Carbon materials are excellent candidates for photovoltaic solar cells: they are Earth-abundant, possess high optical absorption, and maintain superior thermal and photostability. Here we report on solar cells with active layers made solely of carbon nanomaterials that present the same advantages of conjugated polymer-based solar cells, namely, solution processable, potentially flexible, and chemically tunable, but with increased photostability and the possibility to revert photodegradation. The device active layer composition is optimized using ab initio density functional theory calculations to predict type-II band alignment and Schottky barrier formation. The best device fabricated is composed of PC(70)BM fullerene, semiconducting single-walled carbon nanotubes, and reduced graphene oxide. This active-layer composition achieves a power conversion efficiency of 1.3%-a record for solar cells based on carbon as the active material-and we calculate efficiency limits of up to 13% for the devices fabricated in this work, comparable to those predicted for polymer solar cells employing PCBM as the acceptor. There is great promise for improving carbon-based solar cells considering the novelty of this type of device, the high photostability, and the availability of a large number of carbon materials with yet untapped potential for photovoltaics. Our results indicate a new strategy for efficient carbon-based, solution-processable, thin film, photostable solar cells.
Publisher: Wiley
Date: 13-07-2020
Publisher: MDPI AG
Date: 27-03-2020
DOI: 10.3390/S20071875
Abstract: Cancer has been one of the leading causes of death globally, with metastases and recurrences contributing to this result. The detection of circulating tumor cells (CTCs), which have been implicated as a major population of cells that is responsible for seeding and migration of tumor sites, could contribute to early detection of metastasis and recurrences, consequently increasing the chances of cure. This review article focuses on the current progress in microfluidics technology in CTCs diagnostics, extending to the use of nanomaterials and surface modification techniques for diagnostic applications, with an emphasis on the importance of integrating microchannels, nanomaterials, and surface modification techniques in the isolating and detecting of CTCs.
Publisher: American Chemical Society (ACS)
Date: 17-06-2022
DOI: 10.1021/JACS.2C04911
Abstract: Creating high surface area nanocatalysts that contain stacking faults is a promising strategy to improve catalytic activity. Stacking faults can tune the reactivity of the active sites, leading to improved catalytic performance. The formation of branched metal nanoparticles with control of the stacking fault density is synthetically challenging. In this work, we demonstrate that varying the branch width by altering the size of the seed that the branch grows off is an effective method to precisely tune the stacking fault density in branched Ni nanoparticles. A high density of stacking faults across the Ni branches was found to lower the energy barrier for Ni
Publisher: American Chemical Society (ACS)
Date: 18-08-2020
Publisher: Elsevier BV
Date: 10-2022
Publisher: Wiley
Date: 20-02-2023
Abstract: Room‐temperature detection of volatile organic compounds in particle‐per‐billion concentrations is critical for the development of wearable and distributed sensor networks. However, sensitivity and selectivity are limited at low operating temperatures. Here, a strategy is proposed to substantially improve the performance of semiconductor sensors. Tunable oxygen vacancies in thick 3D networks of metal oxide nanoparticles are engineered using deep ultraviolet photoactivation. High selectivity and sensitivity are achieved by optimizing the electronic structure and surface activity while preserving the 3D morphology. Cross‐sectional depth analysis reveals oxygen vacancies present at various depths (≈24% at a depth of 1.13 µm), with a uniform distribution throughout the thick films. This results in ≈58% increase in the sensitivity of ZnO to 20‐ppb ethanol at room temperature while ≈51% and 64% decrease in the response and recovery times, respectively. At an operating temperature of 150 °C, oxygen‐vacant nanostructures achieve a lower limit of detection of 2 ppb. Density functional theory analysis shows that inducing oxygen vacancies reduces activation energy for ethanol adsorption and dissociation, leading to improved sensing performance. This scalable approach has the potential for designing low‐power wearable chemical and bio‐sensors and tuning the activity and band structure of porous, thick oxide films for multiple applications.
Publisher: American Chemical Society (ACS)
Date: 03-12-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA06379G
Abstract: Mitigation of the health hazards caused by Pb is necessary. A liquid metal-based synthesis method delivers unit-cell-thick layers of PbO with comparable piezoelectric response and band gap to PZT thick films while posing reduced toxicity.
Publisher: Springer Science and Business Media LLC
Date: 28-09-2022
DOI: 10.1038/S41467-022-33456-W
Abstract: The water transport along graphene-based nanochannels has gained significant interest. However, experimental access to the influence of defects and impurities on transport poses a critical knowledge gap. Here, we investigate the water transport of cation intercalated graphene oxide membranes. The cations act as water-attracting impurities on the channel walls. Via water transport experiments, we show that the slip length of the nanochannels decay exponentially with the hydrated diameter of the intercalated cations, confirming that water transport is governed by the interaction between water molecules and the impurities on the channel wall. The exponential decay of slip length approximates non-slip conditions. This offers experimental support for the use of the Hagen-Poiseuille equation in graphene-based nanochannels, which was previously only confirmed by simulations. Our study gives valuable feedback to theoretical predictions of the water transport along graphene-based channels with water-attracting impurities.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2NR07147A
Abstract: Bayesian optimisation (BO) has been increasingly utilised to guide material discovery.
Publisher: American Chemical Society (ACS)
Date: 27-04-2021
Publisher: Wiley
Date: 20-01-2022
Abstract: Ceria nanoparticles (NPs) are widely reported to scavenge nitric oxide (NO) radicals. This study reveals evidence that an opposite effect of ceria NPs exists, that is, to induce NO generation. Herein, S ‐nitrosoglutathione (GSNO), one of the most biologically abundant NO donors, is catalytically decomposed by ceria NPs to produce NO. Ceria NPs maintain a high NO release recovery rate and retain their crystalline structure for at least 4 weeks. Importantly, the mechanism of this newly discovered NO generation capability of ceria NPs from GSNO is deciphered to be attributed to the oxidation of Ce 3+ to Ce 4+ on their surface, which is supported by X‐ray photoelectron spectroscopy and density functional theory analysis. The prospective therapeutic effect of NO‐generating ceria NPs is evaluated by the suppression of cancer cells, displaying a significant reduction of 93% in cell viability. Overall, this report is, to the authors’ knowledge, the first study to identify the capability of ceria NPs to induce NO generation from GSNO, which overturns the conventional concept of them acting solely as a NO‐scavenging agent. This study will deepen our knowledge about the therapeutic effects of ceria NPs and open a new route toward the NO‐generating systems for biomedical applications.
Publisher: American Chemical Society (ACS)
Date: 15-02-2019
Abstract: Plasmon-induced hot-carrier transfer from a metal nanostructure to an acceptor is known to occur via two key mechanisms: (i) indirect transfer, where the hot carriers are produced in the metal nanostructure and subsequently transferred to the acceptor, and (ii) direct transfer, where the plasmons decay by directly exciting carriers from the metal to the acceptor. Unfortunately, an atomic-level understanding of the direct-transfer process, especially with regard to its quantification, remains elusive even though it is estimated to be more efficient compared to the indirect-transfer process. This is due to experimental challenges in separating direct from indirect transfer as both processes occur simultaneously at femtosecond time scales. Here, we employ time-dependent density-functional theory simulations to isolate and study the direct-transfer process at a model metal-acceptor (Ag
Publisher: Springer Science and Business Media LLC
Date: 15-12-2013
DOI: 10.1038/NCHEM.1820
Abstract: Chemical functionalization of graphene is promising for a variety of next-generation technologies. Although graphene oxide (GO) is a versatile material in this direction, its use is limited by the production of metastable, chemically inhomogeneous and spatially disordered GO structures under current synthetic protocols, which results in poor optoelectronic properties. Here, we present a mild thermal annealing procedure, with no chemical treatments involved, to manipulate as-synthesized GO on a large scale to enhance sheet properties with the oxygen content preserved. Using experiments supported by atomistic calculations, we demonstrate that GO structures undergo a phase transformation into prominent oxidized and graphitic domains by temperature-driven oxygen diffusion. Consequently, as-synthesized GO that absorbs mainly in the ultraviolet region becomes strongly absorbing in the visible region, photoluminescence is blue shifted and electronic conductivity increases by up to four orders of magnitude. Our thermal processing method offers a suitable way to tune and enhance the properties of GO, which creates opportunities for various applications.
Publisher: American Chemical Society (ACS)
Date: 15-10-2021
Publisher: AIP Publishing
Date: 09-2023
DOI: 10.1063/5.0153029
Publisher: Elsevier BV
Date: 11-2021
Publisher: American Chemical Society (ACS)
Date: 20-01-2021
DOI: 10.1021/JACS.0C12185
Publisher: American Chemical Society (ACS)
Date: 26-10-2020
Publisher: American Chemical Society (ACS)
Date: 16-06-2022
DOI: 10.26434/CHEMRXIV-2022-B61SX
Abstract: The water transport along graphene-based nanochannels has gained significant interest. However, experimental access to the influence of defects and impurities on transport poses a critical knowledge gap. Here, we investigate the water transport of cation intercalated graphene oxide membranes. The cations act as water-attracting impurities on the channel walls. Via water transport experiments, we show that the slip length of the nanochannels decay exponentially with the hydrated diameter of the intercalated cations, confirming that water transport is governed by the interaction between water molecules and the impurities on the channel wall. The exponential decay of slip length approximates non-slip conditions. This offers experimental support for the use of the Hagen-Poiseuille equation in graphene-based nanochannels, which was previously only confirmed by simulations. Our study gives valuable feedback to theoretical predictions of the water transport along graphene-based channels with water-attracting impurities.
Publisher: American Chemical Society (ACS)
Date: 03-07-2014
DOI: 10.1021/JP408325F
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8FD00154E
Abstract: Plasmonic metal nanoparticles can concentrate optical energy and enhance chemical reactions on their surfaces. Plasmons can interact with adsorbate orbitals and decay by directly exciting a carrier from the metal to the adsorbate in a process termed the direct-transfer process. Although this process could be useful for enhancing the efficiency of a chemical reaction, it remains poorly understood. Here, we report a preliminary investigation employing time-dependent density-functional theory (TDDFT) calculations to capture this process at a model metal-adsorbate interface formed by a silver nanoparticle (Ag
Publisher: American Chemical Society (ACS)
Date: 20-09-2019
DOI: 10.1021/JACS.9B08897
Abstract: Two-dimensional (2D) carbides, nitrides, and carbonitrides known as MXenes are emerging materials with a wealth of useful applications. However, the range of metals capable of forming stable MXenes is limited mostly to early transition metals of groups 3-6, making the exploration of properties inherent to mid or late transition metal MXenes very challenging. To circumvent the inaccessibility of MXene phases derived from mid-to-late transition metals, we have developed a synthetic strategy that allows the incorporation of such transition metal sites into a host MXene matrix. Here, we report the structural characterization of a Mo
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1EE00594D
Abstract: Critical to the feasibility of electrochemical reduction of waste NO x (NO x RR), as a sustainable pathway and to close the NO x cycle for the emerging NH 3 economy, is the requirement of inexpensive, scalable and selective catalysts that can generate NH 4 + with high yield, as indicated by our economic modelling.
Publisher: American Chemical Society (ACS)
Date: 05-02-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2TA08306J
Abstract: Relationship between d-metal active species (Co, Ni, & Cu) in Prussian blue analogue derived metal oxide/hydroxide films and the activation energy needed for full conversion of 5-HMF to 2,5-FDCA in alkaline solution.
Publisher: American Chemical Society (ACS)
Date: 06-11-2014
DOI: 10.1021/NN504507U
Abstract: The excellent physical and semiconducting properties of transition metal dichalcogenide (TMDC) monolayers make them promising materials for many applications. The TMDC monolayer MoS2 has gained significant attention as a channel material for next-generation transistors. However, while n-type single-layer MoS2 devices can be made with relative ease, fabrication of p-type transistors remains a challenge as the Fermi-level of elemental metals used as contacts are pinned close to the conduction band leading to large p-type Schottky barrier heights (SBH). Here, we propose the utilization of graphene oxide (GO) as an efficient hole injection layer for single-layer MoS2-based electronic and optoelectronic devices. Using first-principles computations, we demonstrate that GO forms a p-type contact with monolayer MoS2, and that the p-type SBH can be made smaller by increasing the oxygen concentration and the fraction of epoxy functional groups in GO. Our analysis shows that this is possible due to the high work function of GO and the relatively weak Fermi-level pinning at the MoS2/GO interfaces compared to traditional MoS2/metal systems (common metals are Ag, Al, Au, Ir, Pd, Pt). The combination of easy-to-fabricate and inexpensive GO with MoS2 could be promising for the development of hybrid all-2D p-type electronic and optoelectronic devices on flexible substrates.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9FD90014D
Publisher: American Chemical Society (ACS)
Date: 26-04-2022
Abstract: Transforming natural resources to energy sources, such as converting CH
Publisher: American Chemical Society (ACS)
Date: 03-11-2021
Publisher: American Chemical Society (ACS)
Date: 02-02-2023
Publisher: Frontiers Media SA
Date: 29-05-2020
Publisher: American Chemical Society (ACS)
Date: 27-03-2020
DOI: 10.1021/JACS.0C01135
Publisher: American Chemical Society (ACS)
Date: 07-04-2022
Publisher: American Chemical Society (ACS)
Date: 30-11-2022
Publisher: Wiley
Date: 11-11-2022
Abstract: Herein, it is shown that by engineering defects on Ce x Si 1− x O 2− δ nanocomposites synthesized via flame spray pyrolysis, oxygen vacancies can be created with an increased density of trapped electrons, enhancing the formation of reactive oxygen species (ROSs) and hydroxyl radicals in an ozone‐filled environment. Spectroscopic analysis and density functional theory calculations indicate that two‐electron oxygen vacancies (O V 0 ) or peroxide species, and their degree of clustering, play a critical role in forming reactive radicals. It is also found that a higher Si content in the binary oxide imposes a high O V 0 ratio and, consequently, higher catalytic activity. Si inclusion in the nanocomposite appears to stabilize the surface oxygen vacancies as well as increase the reactive electron density at these sites. A mechanistic study on effective ROSs generated during catalytic ozonation reveals that the hydroxyl radical is the most effective ROS for organic degradation and is formed primarily through H 2 O 2 generation in the presence of the O V 0 . Examining the binary oxides offers insights on the contribution of oxygen vacancies and their state of charge to catalytic reactions, in this instance for the catalytic ozonation of organic compounds.
Publisher: American Chemical Society (ACS)
Date: 26-02-2021
Publisher: Wiley
Date: 25-03-2022
Abstract: Inexpensive and energy‐dense Zn metal anodes is key to the promise of aqueous Zn‐ion batteries, which are heralded as an exciting battery chemistry for renewable and stationary storage. Yet, Zn deposition instability under demanding cycling conditions leads to rapid dendritic cell failure, and the hydrogen evolution reaction aggravates the issue. Electrolyte additives are a scalable solution to address the problem, but a high volume fraction is typically required for a noticeable effect. Here, a benign alcohol molecule propylene glycol is presented as an electrolyte additive that enables remarkably stable Zn anode cycling of over 1000 h at a practical 2 mA–2 mA h cm −2 at a low volume concentration when the reference cell shorts only after 30 h. The dramatic performance improvement at the low additive concentration is attributed to the effective morphology regulation and inhibition of hydrogen evolution, as revealed by spectroscopic and microscopic investigations. Ab initio molecular dynamics simulations reveal unprecedented atomistic insights behind the concentration‐dependent effectivity of propylene glycol as an electrolyte additive. Excellent full cell cycling with two different positive host materials, even with high loading, highlights the potential for practical development.
Publisher: American Chemical Society (ACS)
Date: 10-06-2022
DOI: 10.1021/ACS.NANOLETT.2C01615
Abstract: Angstrom-confined solvents in 2D laminates can travel through interlayer spacings, through gaps between adjacent sheets, and via in-plane pores. Among these, experimental access to investigate the mass transport through in-plane pores is lacking. Our experiments allow an understanding of this mass transport via the controlled variation of oxygen functionalities, size and density of in-plane pores in graphene oxide membranes. Contrary to expectations, our transport experiments show that higher in-plane pore densities may not necessarily lead to higher water permeability. We observed that membranes with a high in-plane pore density but a low amount of oxygen functionalities exhibit a complete blockage of water. However, when water-ethanol mixtures with a weaker hydrogen network are used, these membranes show an enhanced permeation. Our combined experimental and computational results suggest that the transport mechanism is governed by the attraction of the solvents toward the pores with functional groups and hindered by the strong hydrogen network of water formed under angstrom confinement.
Publisher: American Chemical Society (ACS)
Date: 24-01-2017
Publisher: American Chemical Society (ACS)
Date: 24-03-2023
Publisher: American Chemical Society (ACS)
Date: 05-2012
DOI: 10.1021/JP301607H
Publisher: Wiley
Date: 29-11-2022
Abstract: MXenes, due to their tailorable chemistry and favourable physical properties, have great promise in electrocatalytic energy conversion reactions. To exploit fully their enormous potential, further advances specific to electrocatalysis revolving around their performance, stability, compositional discovery and synthesis are required. The most recent advances in these aspects are discussed in detail: surface functional and stoichiometric modifications which can improve performance, Pourbaix stability related to their electrocatalytic operating conditions, density functional theory and advances in machine learning for their discovery, and prospects in large scale synthesis and solution processing techniques to produce membrane electrode assemblies and integrated electrodes. This Review provides a perspective that is complemented by new density functional theory calculations which show how these recent advances in MXene material design are paving the way for effective electrocatalysts required for the transition to integrated renewable energy systems.
Publisher: Wiley
Date: 13-07-2020
Publisher: American Chemical Society (ACS)
Date: 10-12-2020
Publisher: Springer Science and Business Media LLC
Date: 07-2011
Publisher: American Chemical Society (ACS)
Date: 02-12-2022
DOI: 10.26434/CHEMRXIV-2022-1Q6GB
Abstract: Materials in 2-dimensional (2D) form often show remarkable properties and unexplored scientific phenomena compared to their bulk form. Layered, van der Waals (vdW) materials have an obvious 2D structure, whereas non-vdW materials have no preference to obtain 2D form. This severely limits the number of currently available 2D non-vDW materials. Here, we introduce a straightforward electrochemical method utilizing the angstrom-confinement of laminar reduced graphene oxide (rGO) nanochannels to obtain 2D transition metal oxides (2D-TMO), a class of non-vdW materials. During synthesis the angstrom-confinement provides a thickness limitation, forcing a sub-unit cell growth of 2D-TMO with oxygen and metal vacancies. The resulting flexible sandwich structure of rGO sheets inserted by a porous polycrystalline network of 2D-TMO is created in centimetre scale. Our accessible method for obtaining 2D-TMO holds high promise to yield exciting properties for fundamental science and applications.
Publisher: American Chemical Society (ACS)
Date: 16-09-2019
Publisher: American Chemical Society (ACS)
Date: 07-11-2017
Publisher: Wiley
Date: 10-03-2021
Publisher: American Chemical Society (ACS)
Date: 12-2022
Publisher: Elsevier BV
Date: 11-2022
Publisher: American Chemical Society (ACS)
Date: 23-06-0200
Abstract: Understanding the interfacial contacts between liquid metals and substrate materials is becoming increasingly important for the fast-rising liquid metal-enabled technologies. However, for such technologies, probing the contact behavior and interfacial charge transport has remained challenging due to the deformable nature of liquid metals and the presence of the surface oxide layer. Here, we encapsulate eutectic gallium indium (EGaIn) micro-/nanodroplets with tungsten trioxide (WO
Publisher: Wiley
Date: 26-04-2017
Publisher: MDPI AG
Date: 18-06-2019
DOI: 10.3390/IJMS20122975
Abstract: Graphene and its derivatives such as graphene oxide (GO) and reduced GO (rGO) offer excellent electrical, mechanical and electrochemical properties. Further, due to the presence of high surface area, and a rich oxygen and defect framework, they are able to form nanocomposites with metal/semiconductor nanoparticles, metal oxides, quantum dots and polymers. Such nanocomposites are becoming increasingly useful as electrochemical biosensing platforms. In this review, we present a brief introduction on the aforementioned graphene derivatives, and discuss their synthetic strategies and structure–property relationships important for biosensing. We then highlight different nanocomposite platforms that have been developed for electrochemical biosensing, introducing enzymatic biosensors, followed by non-enzymatic biosensors and immunosensors. Additionally, we briefly discuss their role in the emerging field of biomedical cell capture. Finally, a brief outlook on these topics is presented.
Publisher: Elsevier BV
Date: 04-2016
Publisher: American Chemical Society (ACS)
Date: 02-12-2020
DOI: 10.26434/CHEMRXIV.13311881.V1
Abstract: Magic-sized clusters (MSCs) of semiconductor are typically defined as specific molecular-scale arrangements of atoms that exhibit enhanced stability. They often grow in discrete jumps, creating a series of crystallites, without the appearance of intermediate sizes. However, despite their long history, the mechanism behind their special stability and growth remains poorly understood. This is particularly true considering experiments that have shown discrete evolution of MSCs to sizes well beyond the “cluster” regime and into the size range of colloidal quantum dots. Here, we study the growth of these larger magic-sized CdSe nanocrystals to unravel the underlying growth mechanism. We first introduce a synthetic protocol that yields a series of nine magic-sized nanocrystals of increasing size. By investigating these crystallites, we obtain important clues about the mechanism. We then develop a microscopic model that uses classical nucleation theory to determine kinetic barriers and simulate the growth. We show that magic-sized nanocrystals are consistent with a series of zinc-blende crystallites that grow layer by layer under surface-reaction-limited conditions. They have a tetrahedral shape, which is preserved when a monolayer is added to any of its four identical facets, leading to a series of discrete nanocrystals with special stability. Our analysis also identifies strong similarities with the growth of semiconductor nanoplatelets, which we then exploit to increase further the size range of our magic-sized nanocrystals. Although we focus here on CdSe, these results reveal a fundamental growth mechanism that can provide a different approach to nearly monodisperse nanocrystals.
Start Date: 05-2021
End Date: 05-2024
Amount: $360,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2017
End Date: 06-2024
Amount: $33,400,000.00
Funder: Australian Research Council
View Funded Activity