Abstract：

　　Electrocatalysts play a vital role in the development of renewable energy technologies based on electrical-chemical energy conversions, such as fuel cells, electrolyzers, photoelectrochemical solar cells and metal-air batteries. Many metallic nanostructures have emerged as promising candidates for such electrocatalytic applications, but the performances are yet to be improved to meet the technical and cost-effectiveness standards for practical implementations. On the other hand, it traditionally relies on the model-catalyst studies of well-defined extended surfaces for mechanistic understanding of electrocatalysis, but discrepancies in catalytic performance and knowledge gaps are also realized to be present between the extended surfaces and nanomaterials. The latter is probably not only due to the intrinsically different bulk and surface structures of materials at these two extremes of size, but also caused by the challenges in probing the active sites and reaction pathways on nanostructured materials.

　　This presentation aims to discuss two examples of our efforts on tailoring metallic nanostructures for electrocatalytic applications: i) highly dense Cu nanowires and ii) shape-controlled Cu nanocrystals for the electroreduction of CO2 and CO. These nanostructures are characterized by combining electron-based microscopic imaging, diffraction and elemental mapping, while the surface structures are probed by using surface-specific adsorption/desorption of small molecules (e.g., COad and OHad). Comparative studies of electrocatalytic performance in stationary H-type cell and fluidized gas-diffusion electrode cell are performed to elucidate the interplay of catalytic kinetics and mass transfer effects in the reaction. Our work highlights the great potential of tailoring nanostructured materials to improve the energy conversion and chemical transformation efficiencies of electrochemical systems.