Addressing the Activity and Selectivity Challenges for CO2 Reduction Via Transition‐metal‐free Homo‐ and Hetero‐biatomic Catalysts Embedded in Two‐dimensional Networks

Designing low-cost and stable electrocatalysts with enhanced activity and selectivity for CO2 valorization to useful chemicals and fuels faces enormous challenges to address the pressing climate change concerns. Synergistic interactions between the atoms in double atom catalysts has emerged as a promising tool to tune and boost CO2 activation and reduction. In this work, we systematically designed highly stable transition-metal-free homo- and hetero-biatomic catalysts based on Al, Be, B and Si supported on TCNQ monolayer for CO2 reduction to C-1 products using dispersion corrected periodic density functional theory calculations. Our findings reveal that transition-metal-free homo-and hetero-biatomic TCNQ catalysts can effectively capture and activate the CO2 molecule with binding energies ranging from 0.09 to 2.35 eV. Extensive free energy calculations to screen the favourable reaction pathways to different C-1 products (CO, HCOOH, CH3OH and CH4) demonstrate that Al-2-TCNQ, AlBe-TCNQ and BeSi-TCNQ stand out as potential candidates for catalyzing CO2RR to methanol in a selective manner, suppressing the competitive HER simultaneously. Remarkably, BeSi-TCNQ shows the best catalytic activity towards CO2 reduction to methanol at record low limiting potential of -0.29 V with spontaneous desorption of the final product. From the in-depth examination of the electronic structure details, integrated projected density of states and crystal orbital Hamilton populations are used to understand and rationalize the binding interactions between the adsorbed CO2 molecule and the homo- or hetero-biatomic TCNQ catalysts. Moreover, the Delta G(*COOH)-Delta G(*CO2) and Delta G(*HCOOH)-Delta G(* OCHO/*COOH) values are found to provide reasonable guidance to evaluate the overall CO2RR performance of homo- and hetero-biatomic TCNQ catalysts, respectively. Therefore, our findings provide significant insights for designing transition metal-free homo- and hetero-biatomic catalysts with intriguing properties for improving CO2 utilization and conversion.