Controllable Regulation of CO2 Adsorption Behavior via Precise Charge Donation Modulation for Highly Selective CO2 Electroreduction to Formic Acid

Abstract

The synthesis of value-added products via CO₂ electroreduction (CO₂ER) is of great significance, but the development of efficient and versatile strategies for the controllable selectivity tuning is extremely challenging. Herein, the tuning of CO₂ER selectivity through the modulation of CO₂ adsorption behavior is proposed. Using the constructed zeolitic MOF (SNNU-339), CO₂ adsorption behavior is controllably changed from *CO₂ to CO₂* via the precise ligand-to-metal charge donation (LTMCD) regulation. It is confirmed that the high electronegativity of the coordinate ligand directly restricts the LTMCD, reduces the charge density on the metal sites, lowers the Gibbs free energy for CO₂* adsorption, and leads to the transformation of CO₂ adsorption mode from *CO₂ to CO₂*. Owing to the modulated CO₂ adsorption behavior and regulated kinetics, SNNU-339 exhibits superior HCOOH selectivity (≈330% promotion, 85.6% Faradaic efficiency) and high CO₂ER activity. The wide applicability of the proposed approach sheds light on the efficient CO₂ER. This study provides a competitive strategy for rational catalyst design and underscores the significance of adsorption behavior tuning in electrocatalysis.