ORCID Profile
0000-0003-2156-0472
Current Organisation
Nanyang Technological University
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Publisher: Elsevier BV
Date: 07-2020
Publisher: Wiley
Date: 27-07-2020
Abstract: The electrochemical nitrogen reduction reaction (NRR) offers a sustainable solution towards ammonia production but suffers poor reaction performance owing to preferential catalyst–H formation and the consequential hydrogen evolution reaction (HER). Now, the Pt/Au electrocatalyst d‐band structure is electronically modified using zeolitic imidazole framework (ZIF) to achieve a Faradaic efficiency (FE) of % with high ammonia yield rate of μg mg cat −1 h −1 under ambient conditions. The strategy lowers electrocatalyst d‐band position to weaken H adsorption and concurrently creates electron‐deficient sites to kinetically drive NRR by promoting catalyst–N 2 interaction. The ZIF coating on the electrocatalyst doubles as a hydrophobic layer to suppress HER, further improving FE by ‐fold compared to without ZIF (ca. 1 %). The Pt/Au‐N ZIF interaction is key to enable strong N 2 adsorption over H atom.
Publisher: Wiley
Date: 27-11-2018
Abstract: Gas–liquid reactions form the basis of our everyday lives, yet they still suffer poor reaction efficiency and are difficult to monitor in situ, especially at ambient conditions. Now, an inert gas–liquid reaction between aniline and CO 2 is driven at 1 atm and 298 K by selectively concentrating these immiscible reactants at the interface between metal–organic framework and solid nanoparticles (solid@MOF). Real‐time reaction SERS monitoring and simulations affirm the formation of phenylcarbamic acid, which was previously undetectable because they are unstable for post‐reaction treatments. The solid@MOF ensemble gives rise to a more than 28‐fold improvement to reaction efficiency as compared to ZIF‐only and solid‐only platforms, emphasizing that the interfacial nanocavities in solid@MOF are the key to enhance the gas–liquid reaction. Our strategy can be integrated with other functional materials, thus opening up new opportunities for ambient‐operated gas–liquid applications.
Publisher: Wiley
Date: 04-07-2022
Abstract: Gas‐phase surface‐enhanced Raman scattering (SERS) remains challenging due to poor analyte affinity to SERS substrates. The reported use of capturing probes suffers from concurrent inconsistent signals and long response time due to the formation of multiple potential probe–analyte interaction orientations. Here, we demonstrate the use of multiple non‐covalent interactions for ring complexation to boost the affinity of small gas molecules, SO 2 and NO 2 , to our SERS platform, achieving rapid capture and multiplex detection down to 100 ppm. Experimental and in‐silico studies affirm stable ring complex formation, and kinetic investigations reveal a 4‐fold faster response time compared to probes without stable ring complexation capability. By synergizing spectral concatenation and support vector machine regression, we achieve 91.7 % accuracy for multiplex quantification of SO 2 and NO 2 in excess CO 2 , mimicking real‐life exhausts. Our platform shows immense potential for on‐site exhaust and air quality surveillance.
Publisher: Wiley
Date: 27-07-2020
Publisher: Wiley
Date: 04-07-2022
Abstract: Gas‐phase surface‐enhanced Raman scattering (SERS) remains challenging due to poor analyte affinity to SERS substrates. The reported use of capturing probes suffers from concurrent inconsistent signals and long response time due to the formation of multiple potential probe–analyte interaction orientations. Here, we demonstrate the use of multiple non‐covalent interactions for ring complexation to boost the affinity of small gas molecules, SO 2 and NO 2 , to our SERS platform, achieving rapid capture and multiplex detection down to 100 ppm. Experimental and in‐silico studies affirm stable ring complex formation, and kinetic investigations reveal a 4‐fold faster response time compared to probes without stable ring complexation capability. By synergizing spectral concatenation and support vector machine regression, we achieve 91.7 % accuracy for multiplex quantification of SO 2 and NO 2 in excess CO 2 , mimicking real‐life exhausts. Our platform shows immense potential for on‐site exhaust and air quality surveillance.
Publisher: AIP Publishing
Date: 27-12-2019
DOI: 10.1063/1.5130649
Abstract: Hybrid materials of earth abundant transition metal dichalcogenides and noble metal nanoparticles, such as molybdenum sulfide (MoSx) and gold nanoparticles, exhibit synergistic effects that can enhance electrocatalytic reactions. However, most current hybrid MoSx-gold synthesis requires an energy intensive heat source of & °C or chemical plating to achieve deposition of MoSx on the gold surface. Herein, we demonstrate the direct overgrowth of MoSx over colloidal nanoporous gold (NPG), conducted feasibly under ambient conditions, to form hybrid particles with enhanced electrocatalytic performance toward hydrogen evolution reaction. Our strategy exploits the localized surface plasmon resonance-mediated photothermal heating of NPG to achieve & °C surface temperature, which induces the decomposition of the (NH4)2MoS4 precursor and direct overgrowth of MoSx over NPG. By tuning the concentration ratio between the precursor and NPG, the amount of MoSx particles deposited can be systematically controlled from 0.5% to 2% of the Mo/(Au + Mo) ratio. Importantly, we find that the hybrid particles exhibit higher bridging and an apical S to terminal S atomic ratio than pure molybdenum sulfide, which gives rise to their enhanced electrocatalytic performance for hydrogen evolution reaction. We demonstrate that hybrid MoSx-NPG exhibits & mV lower onset potential and a 1.7-fold lower Tafel slope as compared to pure MoSx. Our methodology provides an energy- and cost-efficient synthesis pathway, which can be extended to the synthesis of various functional hybrid structures with unique properties for catalysis and sensing applications.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C7CS00786H
Abstract: This review summarizes recent SERS developments, focusing on analyte manipulation strategies and hybrid SERS platforms that venture beyond hotspot engineering.
Publisher: American Chemical Society (ACS)
Date: 10-06-2019
DOI: 10.1021/ACS.ACCOUNTS.9B00163
Abstract: Surface-enhanced Raman scattering (SERS) is a molecular-specific spectroscopic technique that provides up to 10
No related grants have been discovered for Howard Sim Yi Fan.