First-principles study on electrocatalytic CO2 reduction by 2D TM3(HATNA)2: products and mechanism

Abstract

Single-atom catalysts (SACs) have attracted great attention due to their distinct advantages; however, their complicated synthesis procedures have impeded their large-scale application. Additionally, nano-particles or subnano-clusters generated during the synthesis can adversely affect the final performance of the catalysts. The appearance of two-dimensional metal–organic frameworks (2D-MOFs) has provided a new strategy to synthesize SACs. Moreover, highly ordered MOFs have high electrical conductivity and are conducive to electron transfer, which is crucial in improving the electrochemical activity of catalysts. A series of single-atom catalysts TM₃(HATNA)₂ (where TM is one of ten different transition metals) based on 2D-MOFs has been designed using hexazine hetero-trinaphthalene (HATNA) as ligands. The mechanisms and routes of the carbon dioxide reduction reaction (CO₂RR) catalyzed by these materials have been studied using first-principles methods. The results testify that TM₃(HATNA)₂ (TM = Cr, Ru and Rh) may serve as potential catalysts for the CO₂RR with good stability and catalytic activity. The reduction product of Cr₃(HATNA)₂ is methane (CH₄), while that of both Ru₃(HATNA)₂ and Rh₃(HATNA)₂ is methanol (CH₃OH). This work provides a new substrate material for the development of single-atom catalysts with abundant and diverse catalytic products.