Ionic liquid/surfactant-hydrothermal synthesis of dendritic PbS@CuS core-shell photocatalysts with improved photocatalytic performance

Abstract Dendritic PbS@CuS core-shell photocatalysts were synthesized with a two-step method: a dendritic PbS core was formed with an ionic liquid/surfactant-assisted hydrothermal method; a CuS shell was grown with an ion-exchange method. Highly active production of H2 with these dendritic PbS@CuS photocatalysts is reported for the first time. The surface chemistry, morphology, and properties of the crystal lattice of these core-shell nanomaterials were investigated. The effects of the content of the copper (II) nitrate precursor in the nanomaterials on the charge separation, optical properties, and activity for the production of H2 were investigated. The interfacial charge-transfer behaviors of the composite nanomaterials were studied with Cu L3-edge near-edge X-ray-absorption fine-structure (NEXAFS) spectra in situ. A mechanism is proposed based on the results of NEXAFS spectra monitored in situ before and after exposure to solar light. The photoelectron was transferred from CuS to PbS. The proportions of the CuS shells in these dendritic PbS@CuS photocatalysts were optimized to achieve a maximum activity 1736 μmol h−1 g−1 of hydrogen production.