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

Visible-light photocatalytic H2 production by water splitting is of great importance for its promising potential in converting solar energy to chemical energy. ZnxCd1−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 ZnxCd1−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 ZnxCd1−xS/BC are flexible, monolithic and hierarchically porous. The optimized Zn0.09Cd0.91S/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 ZnxCd1−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.