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

Abstract

Photocatalytic reduction of CO₂ into fuel represents a promising strategy for addressing energy and environmental challenges. In this study, nitrogen-doped TiO₂–Ti₃C₂ MXene composites (N-TiO₂–Ti₃C₂) were synthesized using a hydrothermal method. The optimal sample, designated as 2N-TTC, achieved a CH₄ yield of 17.1 µmol g⁻¹ h⁻¹, which is four times higher than that of the undoped counterpart, with a selectivity of 92.5%. Nitrogen doping narrows the band gap, induces oxygen vacancies, and enhances CO₂ adsorption, while the TiO₂/Ti₃C₂ interface forms a Schottky barrier that promotes charge separation. This work provides new insights into the design of efficient MXene-based photocatalysts through band structure and interface engineering.