Boosting visible-light-driven hydrogen evolution through Pt site anchored 2D/2D heterostructure catalyst: Cd-TCPP(Pt)@CdS

Solar-powered water splitting is an up-and-coming method for hydrogen production. Still, it faces several challenges, including improving light responsiveness, maximizing utilization of photocatalyst active sites, and effectively utilizing photo-induced carriers to prevent low hydrogen production. In this research, we propose an approach for designing a 2D/2D heterostructure catalyst, the Cd-TCPP(Pt)@CdS, which consists of 2D CdS nanosheets (NSs) and a two-dimensional (2D) metal-organic framework (MOF) with platinum (Pt) active sites (Cd-TCPP(Pt)), aiming to achieve highly efficient visible-light-driven hydrogen evolution. Firstly, CdS nanosheets exhibit excellent responsiveness to visible light, ensuring robust generation of photo-induced carriers. Secondly, the 2D MOF provides abundant Pt active sites, enhancing electron utilization and reducing the energy barrier for proton reduction. Compared to pure CdS nanosheets (which demonstrate hydrogen production activity of 1.220 mmol/g/h), the newly designed 2D/2D composite catalyst Cd-TCPP(Pt)@CdS exhibits an activity of 13,434 μmol/g/h, representing an 11-fold increase. Impressively, Cd-TCPP(Pt)@CdS maintains a high activity of 3.06 mmol/g/h even under sunlight. DFT calculations were employed to investigate the principle of proton reduction. The suitable bandgap of CdS and energy gap of 2D Cd-TCPP(Pt) contribute to their strong interaction and consequently higher efficiency in hydrogen evolution. The Pt-single atom (SA) also provides sites with low free energy for proton reduction, contributing to improved activity. The photocatalytic performance of Cd-TCPP(Pt)@CdS NSs composites demonstrates a synergistic effect between the 2D inorganic semiconductor and the 2D MOF containing the Pt-site, resulting in enhanced utilization of photo-induced carriers and atoms.