Photoelectrochemical Performance of BiVO₄ Photoanodes Integrated with [NiFe]‐Layered Double Hydroxide Nanocatalysts

Abstract

We immobilized laser‐made nickel iron layered double hydroxide ([NiFe]‐LDH) nanocatalysts on BiVO 4 photoanodes. We compared photoelectrochemical performance of integrated [NiFe]‐LDH–BiVO 4 photoanodes in sulfite‐free aqueous electrolyte with photocurrent generation of neat BiVO 4 photoanodes in aqueous electrolyte with sulfite added as sacrificial hole acceptor. We 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. We also mitigated nanocatalyst aggregation on the BiVO 4 surface by a surfactant that selectively ligated the catalysts or by dispersing the catalyst suspension more rapidly on the photoanode surface. Our rational optimization strategies enhanced photoelectrochemical performance of integrated nanocatalyst photoanodes: Two thirds of all photogenerated holes escaped loss processes in our optimized integrated [NiFe]‐LDH–BiVO 4 photoanodes under 100 mW cm –2 of simulated air mass 1.5 G illumination in aqueous pH 9.2 buffered electrolyte. Our systematic optimization strategies for integration of highly efficient water oxidation nanocatalysts with a visible‐light absorber provide a path towards functional artificial photosynthesis devices.