Computational Screening of Suitable Adatom to Enhance CO<sub>2</sub> Electroreduction on Noble-Metal Based Dual-Atom Catalysts
Sourav Ghoshal, Pranab Sarkar
Abstract
In this work, we have employed first-principles density functional theory (DFT) to account for the comparative efficiency of TiO 2 and g-CN supported Ru 2 and Rh 2 dual-atom catalysts (DACs) for electrochemical CO 2 reduction reactions (CO 2 RRs). Based on DFT calculations, g-CN supported DACs were found to have superior stability and CO 2 reduction activity than that of TiO 2 supported DACs. However, Ru 2 @g-CN and Rh 2 @g-CN double atom catalysts suffer from poor selectivity, as the competitive hydrogen evolution reaction (HER) is likely to occur more favorably than that of CO 2 RR. Here, we have revealed that the replacement of one noble metal by an earth-abundant transition metal can boost the selectivity of CO 2 RRs, while inhibiting the HER. In search of a highly selective and low-cost noble-metal based CO 2 reduction catalyst, we have designed a series of g-CN supported heteronuclear MRu (M = Sc–Zn) dimers and performed a systematic computational screening to identify a suitable adatom (M), which drastically improves the selectivity. Based on the evaluation of stability, activity, and selectivity, VRu@g-CN is finally identified as the best candidate, with the lowest limiting potential of −0.11 V and a high theoretical Faradaic efficiency of 99.57%.