Rational Design of MXene-Supported Single-Atom Catalysts for Electrochemical CO <sub> <b>2</b> </sub> Reduction with Tunable Activity and Product Selectivity
Yitong Yin, Zhe Sun, Maohuai Wang, Bo Liao, Shoufu Cao, H. Chen, Siyuan Liu, Zhaojie Wang, Shuxian Wei, Baojun Wei, Xiaoqing Lu
Abstract
The electrochemical CO 2 reduction reaction (CO 2 RR) represents a promising pathway for the sustainable conversion of CO 2 into energy-dense fuels and commodity chemicals, thereby contributing to carbon neutrality. Nevertheless, achieving simultaneously high catalytic activity and product selectivity remains a formidable challenge. Herein, a comprehensive first-principles investigation integrating density functional theory (DFT) and ab initio molecular dynamics (AIMD) was conducted to elucidate the structure–stability–reactivity correlations of transition metal (TM)-doped Mo 2 TiC 2 single-atom catalysts (SACs) in the context of CO 2 RR. The results demonstrate that the efficient activation of CO 2 originates from the strong orbital hybridization between TM d-states and the CO 2 antibonding orbitals, accompanied by pronounced charge redistribution at the catalytic centers. The TM–Mo 2 TiC 2 catalysts exhibit intrinsic selectivity toward CH 3 OH formation, among which Ni–, Cu–, Os–, and Pt–Mo 2 TiC 2 display remarkably low limiting potentials of −0.39, −0.52, −0.37, and −0.49 V, respectively, outperforming the benchmark Mo 3 C 2 O 2 catalyst (−0.54 V). These findings unveil the fundamental origin of product selectivity and provide atomistic design guidelines for the development of next-generation CO 2 RR electrocatalysts featuring enhanced CH 3 OH selectivity and superior activity.