Shifting and breaking scaling relations at transition metal telluride edges for selective electrochemical CO2 reduction

Abstract

The electrochemical reduction of CO₂ (CO₂RR) to hydrocarbons and alcohols provides a means to solve problems pertaining to fossil energy shortages and environmental pollution. However, developing electrode catalysts that can perform this transformation with a low overpotential and a high product selectivity remains a challenge. Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have emerged as promising catalysts for the CO₂RR, where primarily the edges are responsible for the catalytic activity. Herein by using first-principles density functional theory (DFT), we study 48 TMDC edges with six different chemical compositions (MX₂, M = Mo, W; X = S, Se, Te). By plotting their phase diagrams, we provide guidelines on the synthesis conditions for the edges. Furthermore, by computing the binding energies of key reaction intermediates, we find that the linear scaling relations can be broken by the edge reconstruction and shifted by the chemical composition. Specifically, compared with sulfide and selenide edges, more telluride edges show similar affinity to Cu towards the reaction intermediates. The computed free-energy diagrams show that certain reconstructed telluride edges exhibit high catalytic activity and selectivity for CO₂ reduction to CH₃OH and CH₄. These insights help pave the way for efficient and selective electrochemical CO₂RR on transition metal tellurides.