Breaking scaling relations for efficient CO2 electrochemical reduction through dual-atom catalysts

The electrochemical reduction of CO2 offers an elegant solution to current energy crisis and carbon emission issues, but the catalytic efficiency for CO2 reduction is seriously restricted by the inherent scaling relations between the adsorption energies of intermediates. Herein, by combining the concept of single-atom catalysts and multiple active sites, we design heteronuclear dual-atom catalysts to break through the stubborn restriction of scaling relations on catalytic activity. Twenty-one kinds of heteronuclear transition-metal dimers are embedded in monolayer C2N as potential dual-atom catalysts. First-principles calculations reveal that, by adjusting the components of dimers, the two metal atoms play the role as carbon adsorption site and oxygen adsorption site respectively, which results in the decoupling of key intermediates adsorption energies. Free energy profiles demonstrate that CO2 can be efficiently reduced into CH4 on CuCr/C2N and CuMn/C2N with low limiting potentials of -0.35 V and -0.29 V, respectively. This study suggests that the introduction of multiple active sites in porous two-dimensional materials would provide a great possibility for breaking scaling relations to achieve efficient multi-electron electrocatalytic reactions.