Wittichenite semiconductor of Cu<sub>3</sub>BiS<sub>3</sub> films for efficient hydrogen evolution from solar driven photoelectrochemical water splitting.

Huang, Dingwang; Li, Lintao; Wang, Kang; Li, Yan; Feng, Kuang; Jiang, Feng · Nat Commun · 2021

basic_science · Level V

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Abstract

A highly efficient, low-cost and environmentally friendly photocathode with long-term stability is the goal of practical solar hydrogen evolution applications. Here, we found that the Cu<sub>3</sub>BiS<sub>3</sub> film-based photocathode meets the abovementioned requirements. The Cu<sub>3</sub>BiS<sub>3</sub>-based photocathode presents a remarkable onset potential over 0.9 V<sub>RHE</sub> with excellent photoelectrochemical current densities (~7 mA/cm<sup>2</sup> under 0 V<sub>RHE</sub>) and appreciable 10-hour long-term stability in neutral water solutions. This high onset potential of the Cu<sub>3</sub>BiS<sub>3</sub>-based photocathode directly results in a good unbiased operating photocurrent of ~1.6 mA/cm<sup>2</sup> assisted by the BiVO<sub>4</sub> photoanode. A tandem device of Cu<sub>3</sub>BiS<sub>3</sub>-BiVO<sub>4</sub> with an unbiased solar-to-hydrogen conversion efficiency of 2.04% is presented. This tandem device also presents high stability over 20 hours. Ultimately, a 5 × 5 cm<sup>2</sup> large Cu<sub>3</sub>BiS<sub>3</sub>-BiVO<sub>4</sub> tandem device module is fabricated for standalone overall solar water splitting with a long-term stability of 60 hours.