Predicted C–N Coupling Performance of Lateral Heterostructure Interfaces between Two Types of Layered Materials for Electrochemical Synthesis of Acetamide and Ammonia Via Coreduction 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 NOx, expanding the scope of hydrocarbon products derived from CO2RR. The LHS catalysts identified in this study may be employed to form amide chemicals.

Keywords: Electrosynthesis acetamide, C−N coupling, N-integrated electrocatalytic CO2 reduction, Lateral heterostructures, Two layered materials, Surface-interface effect, electronic properties