Construction of bifunctional CdS-Ti/Ni material for photocatalytic selective oxidation of 1,4-Benzenedimethanol coupled with hydrogen evolution

Controlling the excessive oxidation of 1,4-Benzenedimethanol (1,4-BDM) to selectively produce high-value-added 4-hydroxybenzaldehyde (4-HB) under mild conditions while simultaneously generating H 2 is a challenging problem. In this study, it was found that incorporating Ni into cadmium sulfide (CdS) significantly reduces the bandgap of CdS and adjusts its conduction band position, yet still leads to over-oxidation of 1,4-BDM. To enhance selectivity, we designed and synthesized a bifunctional photocatalyst, CdS-Ti/Ni, with a petal-like structure by integrating both Ni and Ti with CdS. This composite exhibits a bandgap of 2.3 eV, and the synergistic effects of Ti and Ni result in more favorable valence and conduction band positions, thereby demonstrating superior photocatalytic efficiency and selectivity. Within the first 30 minutes, the bifunctional CdS-Ti/Ni achieved a 73 % selectivity for 4-HB. The H 2 evolution rate reached 20.2 mmol·g −1 ·h −1 , which is 13 times higher than that of pure CdS. This study demonstrates that bimetal doping can adjust the energy band structure, photocatalytic H 2 production efficiency and oxidation selectivity of semiconductor materials, offering valuable insights for the design of efficient bifunctional photocatalysts.