Semiconductor/co‐catalyst coupling is considered as a promising strategy to enhance the photoelectrochemical (PEC) conversion efficiency. Unfortunately, this model system is faced with a serious interface recombination problem, which limits the further improvement of PEC performances. Here, a FeNiOOH co‐catalyst with abundant oxygen vacancies on BiVO4 is fabricated through simple and economical NaBH4 reduction to accelerate hole transfer and achieve efficient electron–hole pair separation. The photocurrent of the BV (BiVO4)/Vo‐FeNiOOH system is more than four times that of pure BV. Importantly, the charge transfer kinetics and charge carrier recombination process are studied by scanning photoelectrochemical microscopy and intensity modulated photocurrent spectroscopy in detail. In addition, the oxygen vacancy regulation proposed is also applied successfully to other semiconductors (Fe2O3), demonstrating the applicability of this strategy.

Photoelectrochemical (PEC) water splitting technology is a promising strategy toward producing sustainable hydrogen fuel. However, it is an essential bottleneck to reduce severe charge recombination for the improvement of PEC performance. Construction of heterojunction systems, such as Z-scheme and type II heterojunctions, could efficiently boost charge separation, whereas the mechanism of charge separation is still ambiguous. We describe herein a charge transfer system designed with Bi 2 WO 6 /Bi 2 S 3 (BWO/BS) as a prototype. In this system, Au nanoparticles act as charge relays to engineer a charge transfer pathway, and the obtained BWO/Au/BS photoanode achieves a remarkable photocurrent density of 0.094 mA cm −2 at 1.23 V versus reversible hydrogen electrode (vs RHE), over approximately 1.2 and 2.3 times larger than those of BWO/BS/Au and BWO, exhibiting long-term photostability. More importantly, scanning photoelectrochemical microscopy (SPECM) and intensity-modulated photocurrent spectroscopy (IMPS) studies are performed to in situ-capture the photogenerated hole during the PEC process. Operando analysis reveals that the Zscheme BWO/Au/BS system (1.33 × 10 −2 cm s −1 ) exhibits higher charge transfer kinetics compared to the type II BWO/BS/Au heterostructure (0.85 × 10 −2 cm s −1 ) while efficiently suppressing charge recombination for optimized PEC activity. Note that this smart strategy can also be extended to other semiconductor-based photoanodes such as BiVO 4 . Our study offers an effective pathway for the rational design of highly efficient charge separation for solar conversion based on water splitting.

Developing highly efficient catalytic protocols for C-sp(3)-H bond aerobic oxidation under mild conditions is a long-desired goal of chemists. Inspired by nature, a biomimetic approach for the aerobic oxidation of...

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