Synergistic Coupling of MoS ₂ with Electron-Rich MXene for CO ₂ Conversion to Ethanol under Visible Light

The efficient photocatalytic CO2 reduction to C2 products remains a significant challenge due to sluggish multielectron transfer kinetics and C–C coupling. In this study, MoS2 nanocrystal-decorated Ti3C2 MXene heterostructured photocatalysts with varied loading concentrations have been synthesized using a facile hydrothermal method to enhance selective CO2 reduction to ethanol under visible light. The optimized MS-TC-10 heterostructure exhibits enhanced ethanol production (1633.8 μmol/g), 1.8 times higher than that of bare MoS2, along with improved selectivity (58.12%) and quantum efficiency (1.5%). The broadening of Raman peaks, shifts in Ti 2p, Mo 3d, and S 2p binding energies in the XPS spectrum and a hybrid magnetic signature (sharp and broad peaks at g = 2.013 and 1.94, respectively) in EPR suggest intimate interfacial coupling and electronic interaction between the MoS2 and Ti3C2 MXene. Further, CO2-TPD and FTIR studies provided insights into the CO2 reduction pathway involving the formation of intermediates HCOO–, HCO3–, and carbonate species. CO2-TPD analysis of the MS-TC-10 heterostructure reveals two broad desorption peaks, corresponding to the weak and strong CO2 adsorption sites. The prominent high-temperature desorption peak indicates strong CO2 binding and thereby predominating C2H5OH formation. The overall improved activity is attributed to increased surface-active sites, broadened light harvesting, optimal band structure alignment, and efficient charge transfer across the MoS2–MXene interface. These factors collectively prolong charge carriers’ lifetime, eventually suppressing their recombinations and facilitating a multielectron pathway for C2 product formation. In brief, these results suggest strong CO2 adsorption, efficient photoinduced electron transfer from MoS2 to Ti3C2, and enhanced C–C coupling, enabling selective C2 product formation. This work highlights electron-rich MXene–MoS2 architectures as a promising photocatalyst platform for solar-driven CO2 conversion to value-added chemicals.