Introducing La into a Customized Dual Cu Covalent Organic Framework to Steer CO₂ Electroreduction Selectivity from C₂H₄ to CH₄.

Abstract

Customizing multi-metal site catalysts for achieving controllable CO₂ reduction reaction (CO₂RR) product tuning holds immense promise yet poses formidable challenges. The traditional synthesis method of multi-metal sites is the pyrolysis of metal-containing precursors, which is inherently uncontrollable. Herein, a bottom-up strategy is employed to customize and synthesize multi-metal sites in covalent organic frameworks (COFs), aiming to controllably switch the CO₂ reduction selectivity by regulating the electronic structure of active sites. Briefly, La element provides chances for manipulating and finetuning the electronic structure of the customized dual Cu sites, and converts the main catalytic product of CO₂RR from ethylene to methane. Density functional theory calculations show that the introduction of La alters the electronic structure around Cu, enhances CO₂ and H₂O activation, and changes the formation of energy barriers of key intermediates. To the best of the author's knowledge, this study constructed the first example of customized multi-metal site COF catalysts and provided new ideas for controllable modulation of products.