(Invited) Photo-SECM Measurements of Water Splitting at Single Semiconductor Particles

Abstract

Understanding and improving the properties of photocatalysts can have important implications for energy conversion and storage. Because the activity of heterogeneous catalysts depends strongly on local atomic structures, probing (photo)catalytic reactions at specific local sites is critically important. We have recently reported the use of scanning electrochemical microscopy (SECM) for nanoscale imaging of photoelectrochemical processes at semiconductor surfaces. To illuminate a microscopic portion of the substrate surface facing the SECM probe, a glass-sealed, polished Pt tip simultaneously serves as a nanoelectrode and a light guide. In this paper, we present the results of first nanoscale SECM and photo-SECM experiments with single BiVO4 and SrTiO3 particles. Local mapping of oxygen and hydrogen fluxes produced by water splitting at single semiconductor particles was carried out using chemically modified SECM nanotips.