Ultrastable low-bias water splitting photoanodes via photocorrosion inhibition and in situ catalyst regeneration

Abstract

Photoelectrochemical (PEC) water splitting offers a means for distributed solar hydrogen production. However, the lack of stable and cost-effective photoanodes remains a bottleneck that hampers their practical applications. Here we show that particulate Mo-doped BiVO4 water oxidation photoanodes, without costly and complex surface modifications, can possess comparable stability to that of solar cells. The photoanode exhibits enhanced intrinsic photocorrosion inhibition and self-generation and regeneration of oxygen evolution catalysts, which allows stable oxygen evolution for >1,000 h at potentials as low as 0.4 V versus the reversible hydrogen electrode. The significantly improved photocorrosion resistance and charge separation are attributed to the unusual high-temperature treatment. In situ catalyst regeneration is found to be a site-specific and oxygen evolution rate change-induced process. Our findings indicate the potential of PEC water splitting to compete with other solar hydrogen production solutions, and should open new opportunities for the development of feasible PEC water splitting systems. Using photoelectrodes to split water is a promising approach to convert solar energy to fuel, but photoanode stability is often an issue. Now, a Mo-doped BiVO4 photoanode is shown to stably evolve oxygen for 1,000 h due to in situ regeneration of the catalyst, and inhibition of photocorrosion.