Water oxidation is the rate-determining step for water splitting. The layered double hydroxides (LDHs)

Modification of the semiconductor surface by cobalt-rich catalysts is an effective strategy to improve the photoelectrochemical (PEC) water oxidation kinetics and migration of photogenerated electron and hole. In this study, cobalt phosphide (CoP) nanosheet was integrated on the nanoporous bismuth vanadate (BiVO4) electrode by using the hydrothermal method. The introduction of CoP significantly improved the PEC performance of the photoanode, with a photocurrent up to 4.0 mA cm–2 at 1.23 V (versus RHE) under simulated 100 mW cm–2 irradiation, a 3-fold enhancement over that obtained by the bare BiVO4. The BiVO4+CoP photoanode exhibited an impressive early onset of water oxidation, with a more than 220 mV cathodic shift of the onset potential, superior to the typical Co3O4 and Co–Pi cocatalysts-modified BiVO4 photoanode. Systematic studies show that the improvement in PEC performance by CoP is mainly due to the restraint of surface charge recombination and increase in photovoltage.

The rational design of active photoanodes for photoelectrochemical (PEC) water splitting is crucial for future applications in sustainable energy conversion. A combination of catalysts with photoelectrodes is generally required to improve surface kinetics and suppress surface recombination. In this study, we present WO photoanode modified with the iridium complex [(H dphbpy)Ir (Cp*)Cl]Cl (Ir-PO H ; H dphbpy=2,2'-bipyridine-4,4'-bisphosphonic acid, Cp*=pentamethylcyclopentadiene (WO +Ir-PO H )- for PEC water oxidation. When Ir-PO H is anchored to a WO electrode, the photoanode shows a significant improvement in both photocurrent and faradaic efficiency compared to the bare WO photoanode. Under simulated sunlight illumination (AM 1.5G, 100 mW cm ) with an applied bias of 1.23 V (vs. reversible hydrogen electrode), the photoanode exhibits a photocurrent of 1.16 mA cm in acidic conditions, which is double that of the bare WO photoanode. The faradaic efficiency is promoted from 56 % to 95 %. Kinetic studies reveal that Ir-PO H exhibits a different interfacial charge-transfer mechanism on the WO photoanode for PEC water oxidation compared to iridium oxide. Ir-PO H , as a water-oxidation catalyst, can accelerate the surface charge transfer through rapid surface kinetics.

A cobalt cubane catalyst was immobilized onto a BiVO4 electrode via electrochemical polymerization to fabricate hybrid photoanodes for stable photoelectrochemical water oxidation.

Constructing heterojunctions by coupling dissimilar semiconductors is a promising approach to boost charge separation and charge transfer in photoelectrochemical (PEC) water splitting.