Predicted C–N coupling performance of lateral heterostructure interfaces between two types of layered materials for electrochemical synthesis of acetamide and Ammonia via reduction of CO2 and N2

Abstract

Currently, carbon dioxide reduction (CO₂RR) can convert CO₂ into many high-value hydrocarbon chemicals via electrochemical processes, contributing to achieving energy conservation and emission reduction. Importantly, this method also guides the electrocatalytic synthesis of organonitrogen chemicals via C–C and C–N coupling, such as acetamide synthesis during the coelectroreduction of CO₂ and N₂. Herein, we utilized density functional theory calculations to predict the C–N coupling performance of *CCO and NH₃ for acetamide synthesis on lateral heterostructure (LHS) interfaces of two types of layered materials: Type-A includes NbS₂/MoS₂, NbS₂/TaS₂, NbS₂/WS₂, MoS₂/TaS₂, and TaS₂/WS₂; Type-B contains LHS NbS₂/AlN, NbS₂/GaN, NbS₂/ZnO, MoS₂/AlN, MoS₂/GaN, MoS₂/ZnO, TaS₂/AlN, TaS₂/GaN, TaS₂/ZnO, and WS₂/AlN, WS₂/GaN, WS₂/ZnO. However, achieving simultaneous C–C coupling and C–N coupling remains a great challenge in designing catalysts. To address this, we systemically investigated these LHS catalysts, evaluating factors such as adsorption stability, electroconductivity, catalytic activity, selectivity, and electronic properties. Our findings suggest that MoS₂/WS₂ and NbS₂/ZnO may be potential catalysts, facilitating acetamide synthesis from CO₂ and N₂ reduction with low limiting potentials of − 1.11 and − 0.97 V, respectively. The reaction pathway of CO₂RR involves the formation of CO, C–C coupling via keto − enol tautomerism to form ketene (*CCO), N₂ reduction, and C–N coupling between NH₃ and *CCO to produce *CC(OH)NH₂, finally resulting in acetamide production. Most of these LHS junction catalysts exhibit metallic and semiconductor electronic states, except for MoS₂/GaN, which possesses a large band gap of up to 3.73 eV. Furthermore, our analysis indicates that NbS₂/AlN, NbS₂/GaN, TaS₂/ZnO, WS₂/AlN, and WS₂/ZnO effectively suppress competing byproducts, ensuring the formation of *CCO and promoting nucleophilic reactions leading to *CC(OH)NH₂ during *CC(OH)NH₂. This strategic approach enables the synthesis of organonitrogen chemicals via C–N coupling in the coreduction of CO₂ and NO_x, expanding the scope of hydrocarbon products derived from CO₂RR, the LHS catalysts identified in this study may be employed to form amide chemicals.