Synergistic Ni-Ce bimetallic oxides on flower-cluster-like CdS/Ti3C2 MXene for efficient visible-light-responsive photocatalytic CO2 reduction

Constructing efficient and stable photocatalysts for CO 2 reduction is pivotal for achieving carbon neutrality. Herein, a novel CeNiO x -CdS/Ti 3 C 2 heterostructure was prepared via a facile hydrothermal synthesis combined with an in-situ photodeposition strategy. The integration of Ti 3 C 2 MXene as a conductive bridge significantly suppresses the recombination of photogenerated electron-hole pairs. Crucially, the Ni and Ce dual cocatalysts, introduced via photodeposition, exhibit an exceptional synergistic effect driven by their rich mixed-valence states: Ni sites serve as efficient electron sinks to facilitate the multi-electron reduction process, while Ce species, characterized by their unique 4f orbitals and oxygen storage capacity, promote the absorption and bending activation of CO 2 molecules. Notably, in the absence of sacrificial agents, the optimized CeNiO x -CdS/Ti 3 C 2 catalyst delivers a CO evolution rate of 94.86 μmol g −1 h −1 , which is 22.8 fold greater than pristine CdS. The in-situ DRIFTS and XPS analyses reveal that the mixed-valence bimetallic sites effectively facilitate the formation and stabilization of the *COOH intermediate, thereby optimizing the reaction kinetics. This study offers an innovative perspective on the construction of bimetallic cocatalyst-modified photocatalytic systems for high-performance solar-to-fuel conversion.