Paper SS+EN-TuA7
Surface and Interface Properties of Photoelectrocatalysts for Solar Fuels

Tuesday, October 20, 2015, 4:20 pm, Room 112

Experiments using well-defined model catalysts under controlled conditions and utilizing a range of spectroscopic techniques for characterization of surface and interface properties and the nature and reactivity of surface-bound species can greatly advance understanding of the structure and reactivity of photoelectrocatalysts for solar fuels. We report on several of our recent studies, which include investigations of the effects of dopant incorporation on the structural and chemical properties of the α-Fe₂O₃(0001) surface for water oxidation catalysis, facet-dependent activity and stability of Co₃O₄ nanocrystals towards OER, and the interaction of water with GaP(110), a semiconductor that is known to enable selective CO₂ reduction to methanol in aqueous solutions of CO₂ and nitrogen-containing heteroaromatics. For water oxidation on α-Fe₂O₃, we found that Ni doping in thin films of model catalysts caused a new termination for the films and induced formation of more stable surface-bound OH groups. For the Co₃O₄ system, we used the well-defined morphologies of nanocubes and nanooctahedra to demonstrate that the (111) surfaces vastly out-perform the (100) surfaces for OER activity (overpotential and current density). Finally we have spectroscopically identified in situ the surface-bound species on GaP(110) associated with exposure to water using ambient pressure photoelectron spectroscopy (APPES). These observations on model systems afford further analysis and discussion of the role of surface-bound species in mechanisms for catalyzed water oxidation and CO₂ reduction.