Photoelectrochemical performance of BiVO_4 photoanodes integrated with [NiFe]-layered double hydroxide water oxidation nanocatalysts

Abstract

We integrated laser-made highly active nickel iron layered double hydroxide ([NiFe]-LDH) water oxidn. nanocatalysts, which we developed in our group, with BiVO_4 photoanodes and tested their photoelectrochem. performance under simulated sunlight illumination. We demonstrated decreased aggregation and increased photocurrent generation with nanocatalysts that contain dipos. metals ([NiFe]-LDH and cobalt oxide) as citrate surfactant selectively ligated the catalyst nanoparticles. We also optimized catalyst mass loading, which is a tradeoff between most efficient depletion of photogenerated holes that drive catalytic turnover and parasitic light absorption by the catalyst particles. Integrated [NiFe]-LDH-BiVO_4 photoanodes enhanced photocurrent generation by a factor of 3.3 compared to bare BiVO_4. Comparison of photoelectrochem. performance of integrated [NiFe]-LDH-BiVO_4 photoanodes in sulfite-free aq. electrolyte with photocurrent generation of neat BiVO_4 photoanodes in aq. electrolyte with sulfite added as sacrificial hole acceptor showed that two thirds of all photogenerated holes escaped loss processes in our optimized integrated photoanodes. Our systematic integration strategies provide a path towards functional artificial photosynthesis devices.