Switching the product selectivity from methane to methanol in CO2 hydrogenation via Cu-modified vacancy engineering at MoS2 edge sites

Abstract

The catalytic hydrogenation of carbon dioxide (CO₂) to methanol (CH₃OH) represents a promising strategy for mitigating carbon emissions and closing the carbon cycle. This study demonstrates that the incorporation of Cu into MoS₂ catalysts significantly enhances methanol selectivity and productivity. Through a combination of transmission electron microscope, X-ray diffraction, Raman, electron paramagnetic resonance, X-ray photoelectron spectroscopy, diffuse reflectance Infrared Fourier transform spectroscopy, X-ray absorption spectroscopy, temperature-programmed desorption, and kinetic analysis, we reveal that Cu modifies edge sulfur vacancies, thereby suppressing methane formation and promoting methanol synthesis. At 220 °C and 5 MPa, the 2%Cu/MoS₂ catalyst achieves 85.5% selectivity toward CH₃OH, and the methanol formation rate reaches 7.88 mmol g⁻¹_cat h⁻¹ (0.256 mmol $m_{{}_{{\mathrm{MoS}}_2}}^{-2}$ h⁻¹), representing the highest performance among MoS₂-based catalysts under comparable conditions. This work provides an efficient and potentially scalable approach for designing advanced MoS₂-based catalysts for CO₂ hydrogenation.