Synthesis of a MXene/Metal–Organic Framework Composite for Efficient Supercapacitor and Electrocatalytic CO₂ Reduction

Metal-organic frameworks (MOFs) are remarkable electroactive materials for energy storage and electrochemical CO₂ reduction (CO₂RR) due to their high surface area and tunable pore structures. However, challenges such as stability, conductivity, and product selectivity at high current densities must be addressed to realize their full potential. We crossbreed a zeolite imidazolate framework-8 (ZIF-8)-based MOF with MXene using a simple layer-by-layer deposition technique and investigate the supercapacitive and CO₂RR performances. The as-fabricated MXene/ZIF-8 (MXOF) electrode shows an excellent specific capacitance of 1788 F g^-1 at a current density of 1 A g^-1. The practical MXOF//AC electrode delivers a high energy density and power density of 64.28 Wh kg^-1 and 800 W kg^-1, respectively, with a capacitance of 91% cycle sequence of 10,000 cycles. The electroreduction of CO₂ on the MXOF catalyst demonstrates a Faradaic efficiency of 88% for syngas at a lower drive potential of -1.37 V vs RHE as compared to 98% of MOF at -1.67 V with a H₂/CO ratio close to 1.5-1.8, indicating the potential interplay of catalysts for tuning syngas ratios.