Hole transfer layer of glucose-derived carbon enabled rapid charge transfer and hole storage for efficient water splitting

Charge recombination at the interface of oxygen evolution catalyst (OEC) and BiVO 4 -based photoanode is one of the great challenges to achieve efficient photoelectrochemical (PEC) water splitting due to the poor charge transfer and separation efficiency of BiVO 4 . Herein, a composite photoanode (NiFe/C-Mo:BiVO 4 ) consisting of a molybdenum doped BiVO 4 photoanode, an OEC interfacial layer of NiFeOOH and a tailorable hole transfer layer (HTL) made of glucose-derived carbon in between, was designed and fabricated for highly efficient PEC water splitting. The composite NiFe/C-Mo:BiVO 4 photoanode exhibited the photocurrent density of 5.62 mA cm −2 at 1.23 V RHE and an outstanding photo-stability. Characterization and photoelectrochemical analyses revealed that the inserted carbon HTL, though not active for surface water oxidation kinetics, greatly suppressed the unwanted recombination of electron-hole pairs and drastically improved the transfer and storage of charge carriers at the OEC/BiVO 4 interface. A surface charge separation efficiency of 89 % at 1.23 V RHE and remarkable hole storage properties were obtained. This work afforded a novel approach to the design of low-cost and sustainable HTL integrated photoanodes for efficient PEC water oxidation.