Preparation of nitrogen-doped TiO2 -Ti3C2 MXene composites and its application in photocatalytic reduction of CO2

Abstract

Controlling the emissions and concentration of carbon dioxide (CO2), a significant greenhouse gas contributing to global warming, is crucial. Photocatalytic reduction of CO2 into fuel presents a promising strategy to address current energy challenges and mitigate global warming. In this study, nitrogen-doped TiO2-Ti3C2 MXene composites (N-TiO2-Ti3C2) were successfully synthesized using a hydrothermal method, and their performance and mechanisms in photocatalytic CO2 reduction were systematically investigated. Nitrogen doping effectively regulates the structural and electronic properties of the materials, induces the formation of oxygen vacancies (Ov) that inhibit carrier recombination, and enhances CO2 adsorption. Additionally, the high electrical conductivity of Ti3C2 MXene facilitates the formation of a Schottky barrier with TiO2, effectively promoting the separation of photogenerated electron-hole pairs. The optimal sample 2N-TTC sample achieved a CH4 yield of 17.0 μmol•g -1 •h -1 , which is four times higher than that of the undoped sample (TTC), with a CH4 selectivity of 92.3%. This study provides a new idea for the design of efficient Ti3C2 Mxene-based photocatalysts for CO2 reduction through band regulation and interface optimization.