Bias-free solar-driven hydrogen production from hydrazine wastewater using surface-modified BiVO4-based photoelectrochemical cell

Loading cocatalysts on the photoelectrode surface has been one of the most effective strategies to improve the charge separation and redox reaction kinetics during solar-driven photoelectrochemical (PEC) water splitting. The present study demonstrates that a nanoporous BiVO 4 (BVO) photoanode modified with efficient nickel-iron borate species (NiFe-Bi) exhibits significantly enhanced PEC activity and stability in a simulated hydrazine wastewater environment. The NiFe-Bi cocatalysts can enhance the transfer and separation of interfacial charges and significantly improve the charge injection efficiency. The introduction of hydrazine pollutant with low oxidation potential further promotes the transfer of holes from the surface to the electrolyte while inhibiting the dissolution of VO 4 3- from the BiVO 4 film. Importantly, by combining BVO/NiFe-Bi as a photoanode and a commercial platinum sheet as a cathode, a tandem PEC cell can also be constructed to achieve unbiased solar-driven hydrogen evolution from hydrazine wastewater. The hydrogen evolution rate is approximately 4 μmol h −1 cm −2 , and it still maintains a certain stability under long-term light exposure (AM 1.5 G, 100 mW cm −2 ) for 20 h. This work provides new inspiration for designing solar green hydrogen evolution processes.