Active sites modification and superior carriers separation synergistically boosted hydrogen production of Bi/Bi2MoO6/ZnIn2S4 non-noble metal S-scheme photocatalyst

Abstract

Novel Bi/Bi2MoO6/ZnIn2S4 is not only cost-effective compared to noble metals, but also shows superior hydrogen production. Comprehensive characterization illustrated that the S-scheme heterojunction and excellent photon utilization capability of the photocatalyst were the main factors that enhanced its hydrogen production performance. The X-ray photoelectron spectroscopy illustrated the elemental composition of the catalyst and the presence of Bi metal in ternary heterojunction. The photoluminescence and electrochemical characterization proved that S-scheme heterojunction Bi/Bi2MoO6/ZnIn2S4 promoted the separation of photogenerated carriers. The amount of hydrogen produced by Bi/Bi2MoO6/ZnIn2S4 was 2306.90 µmol g−1 under visible light illumination for 5 h. It was 4.3, 29.6 and 2.2 times more than those of ZnIn2S4, Bi2MoO6/ZnIn2S4 and Pt/ZnIn2S4, respectively. The excellent hydrogen production activity of the ternary complexes may be attributed to the following: (1) Bi/Bi2MoO6 could replace precious metals to enhance reactive sites of ZnIn2S4. (2) Metal Bi could produce surface plasmon resonance effect facilitating light absorption, and Bi acted as an electron bridge promoting charge transfer. (3) The charge transfer mechanism of S-scheme heterojunction and hot electrons injection process of Bi metal synergistically drove the photocatalytic hydrogen production. This work provides an innovative method for the construction of visible-light-driven photocatalysts without using precious metals.