ORCID Profile
0000-0001-7746-5920
Current Organisation
Nanyang Technological University
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Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TA01871A
Abstract: Cu electrodeposition was tuned by phosphate anions and the so-prepared electrodes exhibited outstanding selectivity for CO 2 conversion to HCOOH.
Publisher: Elsevier BV
Date: 05-2005
Publisher: Elsevier BV
Date: 10-2015
Publisher: Wiley
Date: 05-02-2019
Abstract: Vanadium redox flow batteries (VRFBs) rely on ion exchange membranes (IEMs) to separate the positive and negative compartments while maintaining electrical neutrality of the cell, by allowing the transport of ionic charge carriers. Cation exchange membranes (CEMs) and anion exchange membranes (AEMs), the two principal types of IEM, have both been employed in VRFBs. The performance of these IEMs can be influenced by the absorption of species from the electrolyte. In this study, a typical commercial CEM (Nafion 117) and AEM (FAP 450), were examined with respect to vanadium uptake, after exposure to electrolyte at different states of charge. The two types of membrane were found to behave very differently, with the AEM showing very high selectivity for V
Publisher: American Chemical Society (ACS)
Date: 09-06-2015
Publisher: IOP Publishing
Date: 22-06-2022
Abstract: Renewable fuel generation is essential for a low carbon footprint economy. Thus, over the last five decades, a significant effort has been dedicated towards increasing the performance of solar fuels generating devices. Specifically, the solar to hydrogen efficiency of photoelectrochemical cells has progressed steadily towards its fundamental limit, and the faradaic efficiency towards valuable products in CO 2 reduction systems has increased dramatically. However, there are still numerous scientific and engineering challenges that must be overcame in order to turn solar fuels into a viable technology. At the electrode and device level, the conversion efficiency, stability and products selectivity must be increased significantly. Meanwhile, these performance metrics must be maintained when scaling up devices and systems while maintaining an acceptable cost and carbon footprint. This roadmap surveys different aspects of this endeavor: system benchmarking, device scaling, various approaches for photoelectrodes design, materials discovery, and catalysis. Each of the sections in the roadmap focuses on a single topic, discussing the state of the art, the key challenges and advancements required to meet them. The roadmap can be used as a guide for researchers and funding agencies highlighting the most pressing needs of the field.
Publisher: Wiley
Date: 13-08-2023
Abstract: The integration of magnetic fields with magnetoelectric (ME) coupling materials has been recently reported for electrocatalysis applications. Highly efficient energy conversion and storage can be potentially provided by this emerging approach. The ME properties, that is, the coexistence of ferromagnetic (FM) and ferroelectric (FE) ordering in some multiferroic materials, can be manipulated by magnetic or electric fields. The ME coupling can result in unique spin‐related physical properties in catalysts, further leading to interesting effects on electrocatalytic reactions. Herein, a discussion on the ME coupling multiferroic materials, as well as their potential opportunities and challenges as electrocatalysts in selected electrochemical reactions, is provided.
Publisher: Springer Science and Business Media LLC
Date: 20-09-2022
DOI: 10.1038/S41467-022-33000-W
Abstract: Developing efficient catalysts is of paramount importance to oxygen evolution, a sluggish anodic reaction that provides essential electrons and protons for various electrochemical processes, such as hydrogen generation. Here, we report that the oxygen evolution reaction (OER) can be efficiently catalyzed by cobalt tetrahedra, which are stabilized over the surface of a Swedenborgite-type YBCo 4 O 7 material. We reveal that the surface of YBaCo 4 O 7 possesses strong resilience towards structural amorphization during OER, which originates from its distinctive structural evolution toward electrochemical oxidation. The bulk of YBaCo 4 O 7 composes of corner-sharing only CoO 4 tetrahedra, which can flexibly alter their positions to accommodate the insertion of interstitial oxygen ions and mediate the stress during the electrochemical oxidation. The density functional theory calculations demonstrate that the OER is efficiently catalyzed by a binuclear active site of dual corner-shared cobalt tetrahedra, which have a coordination number switching between 3 and 4 during the reaction. We expect that the reported active structural motif of dual corner-shared cobalt tetrahedra in this study could enable further development of compounds for catalyzing the OER.
Publisher: American Chemical Society (ACS)
Date: 29-01-2019
Abstract: The development of commercially friendly and stable catalysts for oxygen reduction reaction (ORR) is critical for many energy conversion systems such as fuel cells and metal-air batteries. Many Co-based perovskite oxides such as LaCoO
Publisher: Elsevier BV
Date: 07-2015
Publisher: American Chemical Society (ACS)
Date: 04-01-2021
Publisher: American Chemical Society (ACS)
Date: 13-09-2018
Publisher: American Chemical Society (ACS)
Date: 08-06-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8TA11994E
Abstract: Recent progress in the usage of metal organic polymers (coordination polymers (CPs), metal–organic frameworks (MOFs), Prussian blue and Prussian blue analogues (PBAs)) as electrodes in Li/Na rechargeable batteries has been reviewed.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8CS00848E
Abstract: A summary and analysis of approaches for measuring the surface areas of metal oxide electrocatalysts for evaluating their intrinsic electrocatalytic activity.
Publisher: Elsevier BV
Date: 10-2018
Publisher: Springer Science and Business Media LLC
Date: 31-03-2021
DOI: 10.1038/S41467-021-22250-9
Abstract: Despite the tremendous progress of coupling organic electrooxidation with hydrogen generation in a hybrid electrolysis, electroreforming of raw biomass coupled to green hydrogen generation has not been reported yet due to the rigid polymeric structures of raw biomass. Herein, we electrooxidize the most abundant natural amino biopolymer chitin to acetate with over 90% yield in hybrid electrolysis. The overall energy consumption of electrolysis can be reduced by 15% due to the thermodynamically and kinetically more favorable chitin oxidation over water oxidation. In obvious contrast to small organics as the anodic reactant, the abundance of chitin endows the new oxidation reaction excellent scalability. A solar-driven electroreforming of chitin and chitin-containing shrimp shell waste is coupled to safe green hydrogen production thanks to the liquid anodic product and suppression of oxygen evolution. Our work thus demonstrates a scalable and safe process for resource upcycling and green hydrogen production for a sustainable energy future.
Publisher: Wiley
Date: 25-03-2021
Publisher: Wiley
Date: 18-02-2021
Publisher: American Chemical Society (ACS)
Date: 15-04-2015
Abstract: Metal vanadium phosphates (MVP), particularly Li3V2(PO4)3 (LVP) and Na3V2(PO4)3 (NVP), are regarded as the next-generation cathode materials in lithium/sodium ion batteries. These materials possess desirable properties such as high stability, theoretical capacity, and operating voltages. Yet, low electrical/ionic conductivities of LVP and NVP have limited their applications in demanding devices such as electric vehicles. In this work, a novel synthesis route for the preparation of LVP/NVP micro/mesoporous 3D foams via assembly of elastin-like polypeptides is demonstrated. The as-synthesized MVP 3D foams consist of microporous networks of mesoporous nanofibers, where the surfaces of in idual fibers are covered with MVP nanocrystallites. TEM images further reveal that LVP/NVP nanoparticles are about 100-200 nm in diameter, with each particle enveloped by a 5 nm thick carbon shell. The MVP 3D foams prepared in this work exhibit ultrafast rate capabilities (79 mA h g(-1) at 100C and 66 mA h g(-1) at 200C for LVP 3D foams 73 mA h g(-1) at 100C and 51 mA h g(-1) at 200C for NVP 3D foams) and excellent cycle performance (almost 100% performance retention after 1000 cycles at 100C) their properties are far superior compared to current state-of-the-art active materials.
Publisher: Springer Science and Business Media LLC
Date: 04-02-2019
DOI: 10.1038/S41467-019-08532-3
Abstract: Exploring robust catalysts for water oxidation in acidic electrolyte is challenging due to the limited material choice. Iridium (Ir) is the only active element with a high resistance to the acid corrosion during water electrolysis. However, Ir is rare, and its large-scale application could only be possible if the intrinsic activity of Ir could be greatly enhanced. Here, a pseudo-cubic SrCo 0.9 Ir 0.1 O 3-δ perovskite, containing corner-shared IrO6 octahedrons, is designed. The Ir in the SrCo 0.9 Ir 0.1 O 3-δ catalyst shows an extremely high intrinsic activity as reflected from its high turnover frequency, which is more than two orders of magnitude higher than that of IrO 2 . During the electrochemical cycling, a surface reconstruction, with Sr and Co leaching, over SrCo 0.9 Ir 0.1 O 3-δ occurs. Such reconstructed surface region, likely contains a high amount of structural domains with corner-shared and under-coordinated IrO x octahedrons, is responsible for the observed high activity.
Publisher: Springer Science and Business Media LLC
Date: 22-01-2016
DOI: 10.1038/SREP19777
Abstract: Thin, robust, lightweight and flexible supercapacitors (SCs) have aroused growing attentions nowadays due to the rapid development of flexible electronics. Graphene-polyaniline (PANI) hybrids are attractive candidates for high performance SCs. In order to utilize them in real devices, it is necessary to improve the capacitance and the structure stability of PANI. Here we report a hierarchical three-dimensional structure, in which all of PANI nanofibers (NFs) are tightly wrapped inside reduced graphene oxide (rGO) nanosheet skeletons, for high-performance flexible SCs. The as-fabricated film electrodes with this unique structure showed a highest gravimetric specific capacitance of 921 F/g and volumetric capacitance of 391 F/cm 3 . The assembled solid-state SCs gave a high specific capacitance of 211 F/g (1 A/g), a high area capacitance of 0.9 F/cm 2 and a competitive volumetric capacitance of 25.6 F/cm 3 . The SCs also exhibited outstanding rate capability (~75% retention at 20 A/g) as well as excellent cycling stability (100% retention at 10 A/g for 2000 cycles). Additionally, no structural failure and loss of performance were observed under the bending state. This structure design paves a new avenue for engineering rGO/PANI or other similar hybrids for high performance flexible energy storage devices.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 10-12-2021
Abstract: Manipulating perovskite surface reconstruction offers a new path for developing advanced water oxidation catalysts.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 25-08-2023
Abstract: Developing technologies based on the concept of methanol electrochemical refinery (e-refinery) is promising for carbon-neutral chemical manufacturing. However, a lack of mechanism understanding and material properties that control the methanol e-refinery catalytic performances hinders the discovery of efficient catalysts. Here, using 18 O isotope–labeled catalysts, we find that the oxygen atoms in formate generated during the methanol e-refinery reaction can originate from the catalysts’ lattice oxygen and the O-2p-band center levels can serve as an effective descriptor to predict the catalytic performance of the catalysts, namely, the formate production rates and Faradaic efficiencies. Moreover, the identified descriptor is consolidated by additional catalysts and theoretical mechanisms from density functional theory. This work provides direct experimental evidence of lattice oxygen participation and offers an efficient design principle for the methanol e-refinery reaction to formate, which may open up new research directions in understanding and designing electrified conversions of small molecules.
Publisher: Elsevier BV
Date: 2015
Publisher: Springer Science and Business Media LLC
Date: 28-04-2023
DOI: 10.1038/S41467-023-38017-3
Abstract: Understanding and mastering the structural evolution of water oxidation electrocatalysts lays the foundation to finetune their catalytic activity. Herein, we demonstrate that surface reconstruction of spinel oxides originates from the metal-oxygen covalency polarity in the M T –O–M O backbone. A stronger M O –O covalency relative to M T –O covalency is found beneficial for a more thorough reconstruction towards oxyhydroxides. The structure-reconstruction relationship allows precise prediction of the reconstruction ability of spinel pre-catalysts, based on which the reconstruction degree towards the in situ generated oxyhydroxides can be controlled. The investigations of oxyhydroxides generated from spinel pre-catalysts with the same reconstruction ability provide guidelines to navigate the cation selection in spinel pre-catalysts design. This work reveals the fundamentals for manipulating the surface reconstruction of spinel pre-catalysts for water oxidation.
Publisher: Wiley
Date: 27-10-2021
Abstract: Developing highly active electrocatalysts for oxygen evolution reaction (OER) is crucial for the scalable production of renewable hydrogen fuels by water electrolysis. Perovskite oxides are extensively studied as OER catalysts as they can have high activity and also offer considerable flexibility in composition and structure. Recently, there are increasingly numerous reports regarding dynamic surface reconstruction of perovskite oxides under OER conditions, with claims that the reconstruction‐derived species are the actual catalysts responsible for the measured OER activity. To enable rational design of perovskite oxides as precatalysts to generate actual active components in situ, gaining essential understanding of their reconstruction behaviors is crucial. This perspective discusses the roles of initial bulk chemistry in the surface evolution process of perovskite oxides during OER, including the dependency of surface stability on electronic structure of the precatalyst and the possibility of occurrence of lattice oxygen evolution reaction and cation leaching on the surface of a perovskite oxide precatalyst. It is reasonably argued that tailoring the bulk properties of perovskite precatalysts, such as electronic structure, crystallographic structure, and ion stoichiometry, can influence the occurrence of surface reconstruction and the formation of actual active surface species.
Publisher: Springer Science and Business Media LLC
Date: 30-06-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 24-06-2014
DOI: 10.1039/C4TA02250E
Location: United States of America
Location: United States of America
No related grants have been discovered for Zhichuan Xu.