Carbon-Supported Nano-Dispersed Metallic Copper Derived From Carbonization of MOF-199 for Electrocatalytic CO2 Reduction

Abstract

CO₂ emissions and accumulation in the ecosystem have exacerbated climate change and increased the global temperature. This study focused on the activation of hydrothermally synthesized Cu metal–organic framework (MOF-199) with potassium citrate (C₆H₅K₃O₇) to produce MOF-derived carbon incorporated with nano-dispersed metallic Cu and oxidative Cu species to facilitate electrochemical CO₂ reduction. Among all MOF samples, the resulting MOF-derived carbon, activated by C₆H₅K₃O₇, demonstrated the highest electrocatalytic current and lowest charge transfer resistance, achieving a Faradaic efficiency exceeding 50% for the production of acetic acid (CH₃COOH) at an applied potential of − 1.1 V (vs RHE). The addition of C₆H₅K₃O₇ during preparation endowed the MOF-derived C with a mesoporous structure, thereby enhancing CO₂ adsorption and activation. A proposed reaction pathway suggested that the generation of nano-dispersed metallic Cu is critical for forming Cu─C bonds for producing CH₃COOH. This study indicates that Cu-containing MOF-derived carbon with beneficial properties for electrocatalytic applications owing to its nanoispersed Cu features could be readily synthesized.