Rational design of MoS2-based dual-atom catalysts for CO2-to-methane conversion: thermodynamic and electronic insights into activity and selectivity†

The rational design of CO₂ electroreduction catalysts requires the establishment of robust structure–activity relationships through precise electronic descriptors. In this study, we employ density functional theory (DFT) calculations to systematically investigate a series of transition metal (TM) dimer-embedded MoS₂ catalysts (TM₂/MoS₂, where TM = Sc–Zn, Pd, Pt, Ru). Our computational screening reveals that the Ni₂/MoS₂ system exhibits exceptional catalytic performance for CH₄ production, achieving a remarkably low limiting potential of −0.88 V, which is significantly superior to that of commercial copper-based catalysts (−1.2 V). From a thermodynamic perspective, we identify a linear correlation between the CO₂ adsorption energy and the adsorption energy of the key reaction intermediate H₂COO. Additionally, electronic structure analysis reveals that the number of d-electrons in the TM in the −2 eV to 0 eV range plays a critical role in determining the overall reaction activity and selectivity. This descriptor-driven framework offers quantitative guidelines for designing dual-atom catalysts in renewable energy conversion systems.