Accelerating surface reaction kinetics and enhancing bulk and surface charge separation in Ag-modified BiVO4 photoanode for photoelectrochemical water splitting

The light collection ability, surface oxidation reaction kinetics, bulk charge carrier separation efficiency, and surface charge injection efficiency play a crucial role in hydrogen production through solar-driven water splitting of semiconductor photoanodes in photoelectrochemical (PEC) system. Surface plasmon resonance (SPR) effect of plasmonic metals exhibits a potential to simultaneously boost the aforementioned performances of semiconductor photoanodes. Herein, the SPR effect of plasmonic Ag nanoparticles is exploited to augment PEC performance of BiVO 4 photoanode. The modification and SPR effect of Ag nanoparticles not only substantially accelerates the reaction kinetics of surface water oxidation but also enhances surface charge injection and bulk charge separation efficiencies of BiVO 4 nanostructure photoanode, leading to 361% enhancement in injection efficiency of surface charges and 126% enhancement in separation efficiency of bulk charges compared with those of pristine BiVO 4 photoanode. As a result, the optimized BiVO 4 /Ag nanostructure photoanode exhibits significantly enhanced PEC performance in Na 2 SO 4 electrolyte without sacrificial agent, and achieves a photocurrent density of 2.3 mA cm −2 at 1.23 V vs. reversible hydrogen electrode, 5 times of unmodified BiVO 4 nanostructure photoanode. This wok offers valuable insights into boosting PEC performance of wide bandgap semiconductor photoanodes through utilizing SPR effect of metals to simultaneously improve surface oxidation reaction kinetics, bulk charge separation and surface charge injection. Download: Download high-res image (131KB) Download: Download full-size image We demonstrate for the first time a novel plasmonic BiVO 4 nanostructure photoanode modified by Ag nanoparticles to achieve solar-driven efficient PEC water splitting by plasmon-induced acceleration of surface reaction kinetics, injection of energetic hot electrons and separation of bulk and surface charges.