Boosting H 2 Production from a BiVO 4 Photoelectrochemical Biomass Fuel Cell by the Construction of a Bridge for Charge and Energy Transfer.

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 H 2 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 BiVO 4 PEC fuel cell is successfully developed by utilizing the low-cost biomass, tartaric acid, as an organic fuel. Thanks to the strong complexation between BiVO 4 and tartaric acid, a bridge for the charge and energy transfer is successfully constructed, which not only improves the photoelectric conversion efficiency of BiVO 4 , but also effectively converts the chemical energy of biomass into H 2 . Remarkably, under AM1.5G illumination, the optimal nanoporous BiVO 4 photoanode exhibits a high current density of 13.54 mA cm -2 at 1.23 V vs reversible hydrogen electrode (RHE) for H 2 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 H 2 production efficiency and provides a new idea for improving the performances and energy conversion efficiency in traditional PEC fuel cells.