Electrocatalytic reduction of CO2 by Co-Cu metastable alloy nanoparticles derived from MOFs

Abstract

The construction of non-noble metal electrodes for the catalytic reduction of CO2 has drawn much attention in recent years. Herein, a facile CoCu@C composite catalyst was synthesized by simply carbonizing CoCu-MOFs, a bimetal MOFs fabricated by integrating Cu2+ ions into the synthesis of ZIF-67. Co-Cu alloy nanoparticles were closely embedded in porous carbon skeleton. Notably, the optimal Co1Cu3@C sample exhibited a total catalytic current of 29.8mA·cm-2 at -0.7V vs RHE, which was 2.56 times of the Co@C catalyst derived from original ZIF-67. Besides, the Co1Cu3@C sample achieved targeted CO:H2 ratios in the CO2 reduction reactions, covering approximately 1:1.7 to 1:4, meeting well with industrial needs. Density Functional Theory (DFT) calculations unveiled an electron migration from Co to Cu within the alloy, indicating the promoted transfer of electrons. Co atoms in Co-Cu alloy was found as the predominant active sites for the reduction of CO2. The study provided a economical CO2 reduction electrocatalyst with cheap feedstock, low operating voltage and specific ratio of syngas. Additionally, this work significantly advances our understanding of Co-Cu alloy electrocatalysts, providing crucial insights for the ongoing evolution of electrocatalyst research in material preparation and theoretical calculations.