Plasmon‐Enhanced Charge Separation and Surface Reactions Based on Ag‐Loaded Transition‐Metal Hydroxide for Photoelectrochemical Water Oxidation

Abstract

Coating photoanodes with transition‐metal hydroxides (TMH) is a promising approach for improving photoelectrochemical (PEC) water oxidation. However, the present system still suffers from high charge recombination and sluggish surface reactions. Herein, effective charge separation is achieved at the same time as boosting the surface catalytic reaction for PEC water splitting through decoration of plasmon metal (Ag) in a semiconductor/TMH coupling system. The kinetic behavior at the semiconductor/TMH and TMH/electrolyte interfaces is systematically evaluated by employing intensity modulated photocurrent spectroscopy, scanning photoelectrochemical microscopy, and oxygen evolution reaction model. It is found that both charge transfer and surface catalysis dynamics are enhanced through local surface plasmon resonance of Ag nanoparticles. The as‐prepared BiVO4/Co(OH)x‐Ag exhibits remarkable activity (≈4.64 times) in PEC water splitting in comparison with pure BiVO4. Notably, this smart approach can be also applied to other TMH (Ni(OH)2), reflecting its universality. This work provides a guiding design method for solar energy conversion with the semiconductor‐TMH system.

Significantly Promoting the Photogenerated Charge Separation by Introducing an Oxygen Vacancy Regulation Strategy on the FeNiOOH Co‐Catalyst

“…The probe molecule, K 3 [Fe(CN) 6 ], is reduced to K 4 [Fe(CN) 6 ] at the SPECM probe, and the tip-generated K 4 [Fe(CN) 6 ] is converted back into K 3 [Fe(CN) 6 ] at the substrate. According to previous theoretical model, [50] it can be seen from Figure 5b that different photoanodes displayed different probe approach curves under both light and dark conditions. The SPECM probe current showed an increasing trend under visible light conditions, which was mainly due to the participation of photogenerated holes in the oxidation process.…”

Recent research progress on operational stability of metal oxide/sulfide photoanodes in photoelectrochemical cells

“…At present, in addition to being unstable, OECs also have insufficient ability to extract photogenerated holes. If the photogenerated holes cannot be effectively extracted in the case of supporting OECs, the interfacial recombination of the photoanode will become severe, resulting in poor stability [133]. To solve this problem, Park et al inserted black phosphorus (BP) as the interface layer between the OECs and BiVO4 to accelerate the speed of photogenerated hole extraction from BiVO4 to the OECs [134].…”

Emerging Surface, Bulk, and Interface Engineering Strategies on BiVO4 for Photoelectrochemical Water Splitting

“…To address the stagnant charge transport dynamics in BiVO 4 photoelectrodes, and hence to increase its overall PEC performance, doping, [32] nanostructuring, [33] cocatalyst loading, [27d] heterostructuring, [34] and plasmonics [35] are adopted and need to explore more for the materials commercialization. Several elaborative reviews on BiVO 4 photoanodes have been published, which primarily describes the synthesis processes involved in growing various BiVO 4 nanostructures, as well as control of their morphology, crystal, and electronic structures.…”