Enhanced photocarrier separation in novel Z-scheme Cu2ZnSnS4/Cu2O heterojunction for excellent photocatalyst hydrogen generation

Abstract

The construction of Z-scheme charge transfer system to achieve high-efficiency photolysis of water to produce hydrogen is a promising approach in the field of photocatalysis. Herein, a series of novel direct Z-scheme Cu2ZnSnS4/Cu2O (CZTS/Cu2O) photocatalytic materials with different Cu2O content is successfully synthesized via simple solvothermal method and oxidation-reduction method. The obtain CZTS/Cu2O composite photocatalysts possess the superior photocatalytic H2 production. Particularly, the CZTS/Cu2O [n(CZTS): n(Cu2O) = 2:1] composite photocatalyst exhibits an exceptionally high photocatalytic hydrogen evolution rate of 897 μ mol g−1 h−1, up to 7.7 times higher than that of pure CZTS. This enhanced photocatalytic activity is attributed to the synergistic effect of the junction and Z-scheme charge transfer mechanism between Cu2O and CZTS, which presents high-efficient charge carriers’ separation. Meanwhile, the good stability of the catalyst has been proved by four cycles of experiments. Thus, this work not only provides insights into the Z-scheme mechanism in heterostructure catalysts but also opens up a promising avenue for developing high-performance photocatalysts for the solar light photocatalytic hydrogen production.