Tailoring Metallic Nanostructures for Electrocatalytic Applications Chao Wang Chemical and Biomolecular Engineering John Hopkins University 12:00 Noon CHEM 260
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. Nanomaterials have emerged as promising candidates for many of such electrocatalytic applications, but the performance still needs to be substantially improved to meet the technical and cost-effectiveness standards for practical implementations. This usually requires comprehensive understanding of the structure-property relationships of the electrocatalysts, which traditionally relies on the model catalyst studies of well-defined extended surfaces. Albeit the progress that has been made, knowledge gaps are also realized to be present between the extended surfaces and nanomaterials, probably not only due to the intrinsically different crystalline and surface structures at these two extreme size dimensions, 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 for the electroreduction of CO2 and CO, and ii) Co/Pt core/shell nanoparticles as sustainable electrocatalysts for the oxygen reduction reaction (ORR). 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). The gained structural information is correlated to the measured catalytic activity, durability and/or selectivity, based on which computational simulations are further performed to understand the established structure-property relationships, depict the active sites and reveal the catalytic enhancement mechanisms. Our work highlights the great potential of tailoring nanostructured materials toward the advancement of renewable energy technologies.