ZnxCd1−xS/bacterial cellulose bionanocomposite foams with hierarchical architecture and enhanced visible-light photocatalytic hydrogen production activity

Abstract

Visible-light photocatalytic H₂ production by water splitting is of great importance for its promising potential in converting solar energy to chemical energy. Zn_xCd_1−xS-based systems are intrinsic visible-light photocatalysts with appropriate electronic band structure and negative reduction potential of photoexcited electrons; however, the H₂ evolution rate is far from satisfactory. A common strategy for improving the photocatalytic activity includes the incorporation of expensive cocatalysts such as noble metals and graphene. Here, we report, for the first time, that high visible-light photocatalytic H₂ production activity can be achieved by organizing Zn_xCd_1−xS nanoparticles into the hierarchical architecture of bacterial cellulose (BC). This is achieved by templated mineralization and ion exchange/seeded growth. The bionanocomposite foams of Zn_xCd_1−xS/BC are flexible, monolithic and hierarchically porous. The optimized Zn_0.09Cd_0.91S/BC exhibits a high H₂ evolution rate of 1450 μmol h⁻¹ g⁻¹ and an excellent apparent quantum efficiency of 12% at 420 nm. The monolithic nature of Zn_xCd_1−xS/BC makes catalyst recovery and recycling possible. The current work manifests that the integration of intrinsic chemical properties with multilength scale structural hierarchy affords performance optimization.