MoS 2 Grain Boundary-Supported Single-Atom Catalysts for Efficient Electrocatalytic CO 2 Conversion to CO

Developing high-efficiency single-atom catalysts (SACs) is essential for the carbon dioxide reduction reaction (CO 2 RR) to produce fuels and chemicals, yet achieving optimal performance remains challenging. In this work, we applied a grain boundary (GB) strategy to rationally design a series of MoS 2 supported SACs for electrocatalytic CO 2 RR. Concretely, different 3d transition metal (TM) atoms were respectively anchored at three types of MoS 2 GBs ( e . g ., 5|7, 8|8, and 4|8 GBs) to form various TM@GB SACs. Our density-functional theory (DFT) calculations revealed that, in comparison with the MoS 2 perfect monolayer, strong interactions between TM atoms and MoS 2 GBs shift down the d-band center of these atoms, hence improving the CO 2 RR activity of TM@GB SACs. Among TM@GBs, V@5|7, Cr@8|8, and V@4|8 GBs were demonstrated to possess excellent catalytic activity, enabling spontaneous CO 2 reduction to CO at applied electrode potentials of −0.30, −0.10, and −0.26 V (vs SHE), respectively. Further, a pivotal descriptor (ψ) based on the inherent structural properties of GB and TM was proposed to correlate the structure with the CO 2 RR activity. Our findings highlight the potential of GB engineering as a strategic tool for modulating the properties of SACs, broadening the applications in catalyst design and optimization.