The Co center is active in electrochemical CO2 reduction (CO2RR), and its activity can be tuned by changing its coordination environment. However, the coordination number around the Co center cannot be readily changed in homogeneous systems owing to bimolecular decomposition of reduced low-coordinate Co species. Herein we report the systematic tuning of N atom numbers from 2 to 5 in the first coordination sphere around Co centers supported on two-dimensional metal–organic layers (MOLs) for the electrochemical CO2RR. The N atoms come from a combination of bipyridine, terpyridine, and phenylpyridine ligands. The Co centers are isolated and stabilized on the MOL to prevent bimolecular decomposition. All of the catalysts, denoted MOL-Co-N x (x = 2–5), are active in reducing CO2 to CO electrochemically, but their activities are highly dependent on the number of coordinating N atoms. MOL-Co-N3 showed the highest current density of 2.3 A mg–1 with a CO Faradaic efficiency of 99% at an overpotential of only 380 mV. Density functional theory calculations attribute the high activity of the Co-N3 center to a balance of ligand field strength and open coordination site: the high ligand field strength promotes back-bonding, while the open coordination site allows HCO3 – assistance, both of which accelerate C–O cleavage. MOLs thus provide a unique platform to systematically study the relationship between the coordination environment and the reactivity of open metal sites in electrocatalysis.

Electroreduction of CO2 (CO2RR) into high value‐added chemicals is an attractive route to achieve carbon neutrality. However, the development of an efficient catalyst for CO2RR is still largely by trial‐and‐error and is very time‐consuming. Herein, we built an electrocatalyst testing platform featuring a home‐built automatic flow cell to accelerate the discovery of efficient catalysts. A fast screening of 109 Cu‐based bimetallic catalysts in only 55 h identifies Mg combined with Cu as the best electrocatalyst for CO2 to C2+ products. The thus designed Mg−Cu catalyst achieves a Faradaic efficiency (FE) of C2+ products up to 80 % with a current density of 1.0 A cm−2 at −0.77 V versus reversible hydrogen electrode (RHE). Systematic experiments with in situ spectroelectrochemistry analyses show that Mg2+ species stabilize Cu+ sites during CO2RR and promote the CO2 activation, thus enhancing the *CO coverage to promote C−C coupling.

No abstract

No abstract

The significant role of hydrogen abstraction in chemistry and biology has attracted many theoretical work to link practical phenomena and mechanistic essence. Here, the photophsical processes and hydrogen abstraction mechanisms...

No abstract

Electroreduction of CO 2 (CO 2 RR) into high value-added chemicals is an attractive route to achieve carbon neutrality. However, the development of an efficient catalyst for CO 2 RR is still largely by trial-anderror and is very time-consuming. Herein, we built an electrocatalyst testing platform featuring a home-built automatic flow cell to accelerate the discovery of efficient catalysts. A fast screening of 109 Cu-based bimetallic catalysts in only 55 h identifies Mg combined with Cu as the best electrocatalyst for CO 2 to C 2 + products. The thus designed MgÀ Cu catalyst achieves a Faradaic efficiency (FE) of C 2 + products up to 80 % with a current density of 1.0 A cm À 2 at À 0.77 V versus reversible hydrogen electrode (RHE). Systematic experiments with in situ spectroelectrochemistry analyses show that Mg 2 + species stabilize Cu + sites during CO 2 RR and promote the CO 2 activation, thus enhancing the *CO coverage to promote CÀ C coupling.