Electrochemical CO₂ conversion to CH₄ over anchored nanohybrid MXene electrocatalyst

The rising concentration of atmospheric CO₂, driven by anthropogenic activities, poses a huge threat to global climate and environmental health. This study investigates the development of a novel Ti₂C–ZnO nanohybrid as an efficient electrocatalyst for CO₂ electrochemical reduction (CO₂-ECR), providing a sustainable approach to mitigating CO₂ emissions while generating valuable chemical feedstocks. The nanocomposite was synthesized via selective etching of Ti₂AlC MAX phases to produce Ti₂C MXene, followed by hydrothermal synthesis of ZnO nanoparticles and subsequent wet impregnation. Comprehensive structural, morphological and electrochemical analyses were conducted to evaluate the physio-structural performance of the synthesized electrocatalyst. Among the evaluated catalysts, the Ti₂C–ZnO₅ nanocomposite demonstrated outstanding CO₂-ECR activity and product selectivity, achieving a remarkable Faradaic efficiency (FE) of 99.7 % for CH₄ at an applied potential of −0.56 V_RHE. This marks a 35.2 % improvement over pristine Ti₂C and ZnO counterparts, while concurrently suppressing the competitive hydrogen evolution reaction (HER). This remarkable enhancement in catalytic activity is ascribed to the synergetic interplay between Ti₂C and ZnO, which facilitates efficient charge transfer, increases the electrochemically active area, and stabilizes intermediates during CO₂ reduction reaction. The experimental findings were corroborated with density functional theory (DFT) calculations to further enhance and validate the findings. This study provides new insights into MXene-based hybrid catalysts and highlights their potential in sustainable methane production, offering a green alternative to conventional fossil-fuel-based methods via CO₂ utilization.