Interface engineering of Platinum-Copper alloy/titanium dioxide for enhanced photocatalytic carbon dioxide reduction

To develop an efficient photocatalytic carbon dioxide (CO₂) reduction aimed at mitigating CO₂ emissions and greenhouse effects, we propose a straightforward strategy involving hydrogen reduction treatment of PtCu/Ti to create the PtCu/Ti-H₂ catalyst with a distinctive interface structure. Compared with the fresh PtCu/Ti catalyst and the benchmark anatase TiO₂, the CH₄ production of the PtCu/Ti-H₂ catalyst increased by 2 times and 81.6 times, respectively. Comprehensive characterizations confirmed the formation of Pt^δ+-Ov-Ti³⁺ and Cu^δ+-Ov-Ti³⁺ interface structures on the hydrogen-treated PtCu/Ti-H₂ catalyst, enhancing light absorption and the separation of photogenerated charge carriers. Further investigation into the reaction mechanism revealed that the Pt^δ+-Ov-Ti³⁺ and Cu^δ+-Ov-Ti³⁺ species on PtCu/Ti-H₂ serve as more favorable sites for CO₂ adsorption and activation, promoting an enhanced formaldehyde mechanism. This study not only elucidates the relation between photocatalytic CO₂ reduction activity and the PtCu/Ti interface structure but also offers a novel strategy for designing alloy/oxide-based catalysts for CO₂ photoreduction, overcoming the limitations of previous studies that focused on metal or vacancy systems.