Highly Selective CO Electroreduction to CH by In Situ Generated Cu O Single-Type Sites on a Conductive MOF: Stabilizing Key Intermediates with Hydrogen Bonding.

It is still a great challenge to achieve high selectivity of CH in CO electroreduction reactions (CO RR) because of the similar reduction potentials of possible products and the sluggish kinetics for CO activation. Stabilizing key reaction intermediates by single type of active sites supported on porous conductive material is crucial to achieve high selectivity for single product such as CH . Here, Cu O(111) quantum dots with an average size of 3.5 nm are in situ synthesized on a porous conductive copper-based metal-organic framework (CuHHTP), exhibiting high selectivity of 73 % towards CH with partial current density of 10.8 mA cm at -1.4 V vs. RHE (reversible hydrogen electrode) in CO RR. Operando infrared spectroscopy and DFT calculations reveal that the key intermediates (such as *CH O and *OCH ) involved in the pathway of CH formation are stabilized by the single active Cu O(111) and hydrogen bonding, thus generating CH instead of CO.