Enhancing the electrochemical conversion of carbon dioxide to value-added products on zinc oxide-MXene nanocomposite

Abstract

Developing efficient and sustainable catalysts for CO₂ electroreduction is critical to addressing the rising atmospheric CO₂ levels and mitigating climate change. This study presents a novel ZnO-MXene (Ti₂C) nanocomposite as a high-performance electrocatalyst for CO₂ conversion, offering a strategic approach for generating valuable carbon-based feedstocks. The ZnO-MXene nanocomposites were synthesized via the wet impregnation method and comprehensively characterized using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). Electrochemical performance was assessed through linear sweep voltammetry (LSV), cyclic voltammetry (CV), and controlled potential coulometry, with gas chromatography employed for product quantification. ZnO-MX₁₀ and ZnO-MX_2.5 exhibited high selectivity for CH₄ (79.3 % Faradaic efficiency, FE) at −0.56 V_RHE and CO (76.8 % FE) at −0.78 V_RHE, while significantly suppressing competing H₂ evolution. The synergistic interaction between ZnO and MXene enhances charge transfer, increases active sites, and improves surface area, leading to superior electrochemical performance. Overall, this work introduces a novel ZnO-MXene nanocomposite with dual selectivity for CO and CH₄, enhanced electroactive surface, and long-term stability. Unlike conventional Zn-based catalysts, which exhibit either limited selectivity or rapid degradation, our composite achieves 79.3 % Faradaic efficiency for CH₄ and 76.8 % for CO, while suppressing H₂ evolution. This unique tunability and stability make ZnO-MXene an attractive alternative to noble metal-based electrocatalysts.