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Designing and synthesising electrocatalysts with low overpotential, high activity, selectivity, and stability for the CO 2 reduction reaction (CO 2 RR) is crucial for addressing environmental challenges and realising the artificial carbon cycle. In this study, we successfully synthesised a nitrogen-doped carbon-supported diatomic electrocatalyst comprising atomically dispersed CuN 4 and NiN 4 bimetallic centers. This was confirmed through extensive characterisation using high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption spectroscopy techniques. The as-synthesised CBN-CuNi electrocatalyst exhibited exceptional selectivity and stability in CO 2 RR. Over a wide potential range from − 0.60 to − 1.10 V vs RHE, CBN-CuNi maintained over 90% Faraday efficiency for CO (FE CO) production. Notably, at − 0.9 V vs RHE, it achieved a remarkable selectivity with a maximum FE CO of 97.9%, surpassing single metal catalysts, including CBN-Ni and CBN-Cu. Furthermore, CBN-CuNi demonstrated outstanding stability, sustaining over 90% FE CO production for 40 h of continuous electrolysis, surpassing many existing electrocatalysts. These findings highlight the potential of the as-synthesised bimetallic electrocatalyst CBN-CuNi in the electrochemical reduction of CO 2 to CO, contributing to advancing the artificial carbon cycle and addressing environmental concerns. [Display omitted] • A novel nitrogen-doped carbon-supported electrocatalyst CBN-CuNi is synthesized. • The CuN 4 /NiN 4 coordination environment of CBN-CuNi promotes the convert CO 2 into CO. • CBN-CuNi shows over 90% FE CO from − 0.6 to − 1.1 V, especially 97.9% FE CO at − 0.9 V. • CBN-CuNi can maintain FE CO of exceeding 90% at − 0.8 V during 40 h of electrolysis. [ABSTRACT FROM AUTHOR]

A set of crosslinked quaternized polybenzimidazole (cQAPBI-nC) membranes with varying carbon chain lengths of crosslinking agents are designed and prepared through grafting and crosslinking reactions for their applications in electrocatalytic CO 2 reduction reaction (CO 2 RR). The cQAPBI-6C membrane stands out among all the cQAPBI-nC membranes due to its ingenious construction of a hydrophilic/hydrophobic micro-phase separation structure. As a result, this membrane exhibits exceptional OH− conductivity and selectivity of 79.40 mS cm−1 and 54.73%, respectively, surpassing those of the commercially available FAA-3-PK-130 membrane (OH− conductivity: 33.38 mS cm−1, selectivity: 39.00%). Moreover, the cQAPBI-6C membrane has excellent mechanical and alkaline stabilities. In the self-made membrane electrode assembly reactor, the cQAPBI-6C membrane demonstrates higher CO Faraday efficiency (FE) compared with FAA-3-PK-130 membrane at −100 ∼ −160 mA cm−2. Furthermore, the cQAPBI-6C membrane can operate continuously and stably for over 32 h at −150 mA cm−2, and the CO FE and voltage maintain at around 95% and −3.7 V. These findings provide strong evidence to support the practical significance of the proposed modification strategy in the development of polybenzimidazole-based anion exchange membranes for CO 2 RR applications. [Display omitted] • cQAPBI membranes were prepared via grafting and crosslinking strategies for CO 2 RR. • The obvious micro-phase separation structure is given to cQAPBI-6C membrane. • cQAPBI-6C membrane has outstanding OH−conductivity and selectivity. • cQAPBI-6C membrane shows excellent CO FE, current density and durability for CO 2 RR. [ABSTRACT FROM AUTHOR]