MXene-based electrocatalysts for CO₂ reduction: advances, challenges, and perspectives

The electrochemical reduction of carbon dioxide (CO₂) is a crucial step toward a sustainable carbon economy, enabling the conversion of greenhouse gases into valuable fuels and chemicals. Among the emerging materials for this transformation, two-dimensional (2D) MXenes comprising transition-metal carbides, nitrides, and carbonitrides are notable due to their tunable surface chemistry and high conductivity. This review comprehensively analyzes recent advancements in MXene-based electrocatalysis for the CO₂ reduction reaction (RR) and explores the unique electronic properties of MXenes that drive their catalytic performance. Composition, surface terminations, defect engineering, and interfacial dynamics dictate activity and selectivity and are analyzed to contextualize the structure-function correlations. This work discusses state-of-the-art strategies to enhance the performance of MXene-based electrocatalysts, including compositional modifications, heteroatom doping, and heterostructure integration. Mechanistic insight into the CO₂RR is examined to pinpoint the advantages and challenges of MXenes in the overall reaction network. Finally, this work presents a forward-looking perspective, outlining challenges and emerging opportunities for MXenes in driving sustainable CO₂ electrocatalytic conversion technology.