Front-Surface Potential of Platinized p -InP Photocathodes Probed by Dual-Working-Electrode Measurements

High Resolution Image Download MS PowerPoint Slide The front-surface potential ( E fr ) of p -InP/Pt photocathodes performing the hydrogen-evolution reaction has been probed under operating conditions using a dual-working-electrode (DWE) method. The DWE data are consistent with expectations for proposed stability mechanisms for p -InP photocathodes. Specifically, E fr for Pt-modified p -InP adopts a value near the reversible hydrogen electrode (RHE) potential, consistent with kinetic suppression of metallic In 0 formation. The data provide a rapid, operando metric of interfacial catalyst activity, and indicate that E fr for the p -InP/Pt junction is governed by surface catalytic kinetics rather than by the applied back-contact potential ( E b ).