Construction of 0D/3D CdS/CoAl-LDH S-scheme heterojunction with boosted charge transfer and highly hydrophilic surface for enhanced photocatalytic hydrogen evolution and antibiotic degradation

Abstract

Energy band matching coupled with intimate interface in a heterojunction is the prerequisite for achieving the separation of photogenerated carriers. Herein, 0D CdS nanospheres were uniformly anchored in 3D flower-like CoAl layered double hydroxide (CoAl-LDH) spheres via a hydrothermal process. The unique porous structure and abundant hydrophilic groups can significantly promote the interactions between catalyst and solutions and thus facilitate the photocatalytic reaction. The appropriately staggered band structures can trigger the formation of S-scheme heterojunction, and the tight connection between the CdS and CoAl-LDH offers more charge transport channels, thereby accelerating the charge transfer. The optimized CdS/CoAl-LDH nanohybrid presents a photocatalytic hydrogen evolution of 6.19 mmol/g/h and tetracycline hydrochloride (TC) degradation efficiency of 92.2 % in 50 min. Moreover, the Cd2+ ion concentration measured by ICP-OES verifies the alleviation of photocorrosion, and the DFT calculations further demonstrate the higher hydrophilia, lower H2 absorption energy and stronger charge interactions of CdS/LDH hybrid. This work provides a feasible strategy to efficiently utilize the photoinduced carries by constructing a highly hydrophilic S-scheme heterojunction.