Nanoparticles? the Universe?
Surface/Interface Catalysis (Photocatalysis)
In situ studies of catalytic processes by various spectroscopic techniques are of significant importance in heterogeneous catalysis. It will help to understand the detailed reaction mechanisms and also guide the design of highly efficient catalysts in a more scientific way. Our group devotes continuously to unveil the structure-activity relationship of nanoalloy catalysts in heterogeneous catalysis by in situ SHINERS, which has advantage of detection signals in low wavenumber region, high sensitivity and wide generality et. al. By assembling various nanocatalysts onto the surface of shell-isolated nanoparticles (SHINs), SHINERS can be used to in situ monitor the reaction processes and intermediates, such as oxygen species, surface hydroxyl group and surface oxide, which are difficult to study directly by other techniques.
Lately investigation on energy conversion has been attracted much attention in designing of solar fuel and solar cell, while the efficiency is the most important limitation. Our group focuses on SPR enhanced photocatalysis. SPR is always accompanied by valuable physical effects such as electromagnetic near-field enhancement, heat generation, excitation of hot-electrons and surface potential change. These effects can enhance the chemical reaction and convert the solar energy directly into a chemical fuel. Tuning SPR effect by changing the material, morphology, coupling condition, we can easily control the light harvesting mechanisms. Thus, new catalysts formed by combining traditional photocatalyst with plasmonic structures are under study in our lab.
Recently, gold decorated wide band metal-oxide semiconductors have been emerged as a novel visible-light photocatalysts to improve the solar-light harvesting and surface chemical reaction. However, it has been hard so far to confirm the pure SPR effect. Our group combines experimental characterization studies with computational modeling to gain better insight into the mechanisms at molecular level. Techniques such as in situ SERS or SHINERS and photoelectron-chemistry experiments allow us to monitor the catalysts properties and surface reaction processes.