Anodic Product-Derived Bi-MOF as Pre-catalyst for Cathodic CO2 Reduction: A Novel Strategy for Paired Electrolysis

The paired electrolysis coupling the reduction of CO2 to value-added molecules like HCOOH with the oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is one promising strategy of great economic and environmental benefits. Herein, a Ni(OH)(2) anode for the selective oxidation of HMF to FDCA was fabricated, revealing the significant part of the membrane in electrocatalytic procedure. With the FDCA product as a di-carboxylic acid ligand, one new bismuth-based metal-organic framework material was synthesized, which is capable of catalyzing the reduction of CO2 to HCOOH with over 95 % Faradaic efficiency (FE) and an average current density of 19.6 mA cm(-2) at -1.2 V vs. reversible hydrogen electrode (RHE). With this inner relationship, paired electrolysis was conducted with cathodic potential fixed at -1.2 V vs. RHE, producing the HCOOH with 95.6 % FE and FDCA with 75 % FE in one single electrolyzer.

Automated summary

This study presents a paired electrolysis strategy for reducing CO2 to HCOOH and oxidizing HMF to FDCA, which has great economic and environmental benefits. A Ni(OH)(2) anode was fabricated, showing the significant role of the membrane in the electrocatalytic process. A novel bismuth-based metal-organic framework material was synthesized, which effectively catalyzed the reduction of CO2 to HCOOH. By fixing the cathodic potential, high FE of HCOOH and FDCA can be simultaneously produced in a single electrolyzer.