Enhancing Electrocatalysis\nof CO<sub>2</sub> to Ethanol\nvia Intercalated Electron Boosters in an Atomically Dispersed Ca–N<sub>4</sub>‑Doped Graphene Bilayer

We report the development of atomically dispersed Ca–N<sub>4</sub>-doped graphene bilayers with single intercalated alkaline\nearth metal (AEM) atoms, denoted as CaN<sub>4</sub>–AEM–CaN<sub>4</sub>, designed to enhance the electrocatalytic conversion of CO<sub>2</sub> to C<sub>1</sub> and C<sub>2</sub> products. These catalysts\nsignificantly improve the CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) activity and fine-tune the selectivity between C<sub>1</sub> and C<sub>2</sub> pathways. Based on our theoretical findings, we\npropose an electron transfer mechanism where AEM atoms serve as electron\ndonors across both layers during nonadsorbed intermediate processes\nand as electron boosters that facilitate electron transfer from the\nnonadsorbed to the adsorbed layer during adsorption, thereby enhancing\ncatalytic performance. AEMs also influence the reaction pathways,\npromoting the formation of more valuable C<sub>2</sub> products by\nadjusting selectivity. Among the CaN<sub>4</sub>–AEM–CaN<sub>4</sub> systems, CaN<sub>4</sub>–Sr–CaN<sub>4</sub> stands out with a superior limiting potential (−0.93 V),\ndemonstrating exceptional electrochemical catalytic activity for CO<sub>2</sub>-to-ethanol conversion. This study underscores the potential\nof CaN<sub>4</sub>–AEM–CaN<sub>4</sub> catalysts for\nenhancing multicarbon CO<sub>2</sub>RR and provides key insights into\nthe electron transfer mechanisms that drive their activity and selectivity.