Enhanced Photoelectrochemical Performance of Si Photocathodes with Deposition of Noble Metal Particles

In this study, an Si nanowire (SiNW) array was prepared on a single-crystal Si wafer by a facile Ag-assisted wet-chemical etching route, followed by deposition of ultrathin Pt nanoparticles for enhancing the photoelectrochemical (PEC) performance. It was demonstrated that the PEC performance of SiNWs was enhanced significantly after Pt modification. A higher photocurrent density of − 12 mA cm −2 was achieved in Pt/SiNWs at − 0.845V versus a reversible hydrogen electrode, which was six times greater than that of bare SiNWs. The mechanism for the enhanced PEC performance was analyzed by combining the electrochemical impedance spectra and Mott–Schottky plots. As a result, the mechanism was attributed to the improved charge transfer ability at the solid electrode/electrolyte interfaces.