Dynamic semiconductor-electrolyte interface for sustainable solar water splitting over 600 hours under neutral conditions.

Gao, Rui-Ting; Nguyen, Nhat Truong; Nakajima, Tomohiko; He, Jinlu; Liu, Xianhu; Zhang, Xueyuan; Wang, Lei; Wu, Limin · Sci Adv · 2023

basic_science · Level V

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Abstract

Photoelectrochemical (PEC) water splitting that functions in pH-neutral electrolyte attracts increasing attention to energy demand sustainability. Here, we propose a strategy to in situ form a NiB layer by tuning the composition of the neutral electrolyte with the additions of nickel and borate species, which improves the PEC performance of the BiVO<sub>4</sub> photoanode. The NiB/BiVO<sub>4</sub> exhibits a photocurrent density of 6.0 mA cm<sup>-2</sup> at 1.23 V<sub>RHE</sub> with an onset potential of 0.2 V<sub>RHE</sub> under 1 sun illumination. The photoanode displays a photostability of over 600 hours in a neutral electrolyte. The additive of Ni<sup>2+</sup> in the electrolyte, which efficiently inhibits the dissolution of NiB, can accelerate the photogenerated charge transfer and enhance the water oxidation kinetics. The borate species with B─O bonds act as a promoter of catalyst activity by accelerating proton-coupled electron transfer. The synergy effect of both species suppresses the surface charge recombination and inhibits the photocorrosion of BiVO<sub>4</sub>.