Boosting H₂ Production from a BiVO₄ Photoelectrochemical Biomass Fuel Cell by the Construction of a Bridge for Charge and Energy Transfer

Abstract Utilizing a photoelectrochemical (PEC) fuel cell to replace difficult water oxidation with facile oxidation of organic wastes is regarded as an effective method to improve the H₂ production efficiency. However, in most reported PEC fuel cells, their PEC activities are still low and the energy in organic fuels cannot be effectively utilized. Here, a unique BiVO₄ PEC fuel cell is successfully developed by utilizing the low‐cost biomass, tartaric acid, as an organic fuel. Thanks to the strong complexation between BiVO₄ and tartaric acid, a bridge for the charge and energy transfer is successfully constructed, which not only improves the photoelectric conversion efficiency of BiVO₄, but also effectively converts the chemical energy of biomass into H₂. Remarkably, under AM1.5G illumination, the optimal nanoporous BiVO₄ photoanode exhibits a high current density of 13.54 mA cm⁻² at 1.23 V vs reversible hydrogen electrode (RHE) for H₂ production, which is higher than that of previously reported PEC water splitting systems or PEC fuel cell systems. This work opens a new path for solving the low PEC H₂ production efficiency and provides a new idea for improving the performances and energy conversion efficiency in traditional PEC fuel cells.