ZIF-derived bifunctional Cu@Cu–N–C composite electrocatalysts towards efficient electroreduction of oxygen and carbon dioxide

• Published in: Electrochimica acta Vol. 331; p. 135273
• Main Authors: Chen, Xiang-Lan, Ma, Lu-Shan, Su, Wan-Yu, Ding, Lin-Fei, Zhu, Hai-Bin, Yang, Hui
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 20.01.2020; Elsevier BV
• Subjects: Bifunction; Carbon; Carbon dioxide; Carbon dioxide reduction; Catalytic converters; Copper; Electrocatalysts; Morphology; N-codoped carbon; Open circuit voltage; Oxygen reduction; Oxygen reduction reactions; Zinc oxide; Oxygen reduction; Cu; Carbon dioxide reduction; N-codoped carbon; Copper; Bifunction
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2019.135273

A Cu@Cu–N–C composite electrocatalyst with metallic Cu NPs and Cu(II)-Nx species embedded into the carbon matrix was pyrolyzed from ZIF-8 precursor through the formation of Cu(OH)2@ZIF-8. The optimal Cu@Cu–N–C catalyst obtained at 1000 °C features a hollow polyhedral morphology, which is resulted from the carbothermal reaction of in-situ generated Cu2O and ZnO with carbon beyond 800 °C. The best-performance Cu@Cu–N–C exhibits an impressive catalytic bifunction towards oxygen reduction reaction (ORR) and carbon dioxide reduction (CO2RR) which is assumed to be imparted by the unique Cu(0)-Cu(II)-Nx active sites. In alkaline electrolyte, it shows the ORR performance (E1/2 = 0.83 V vs RHE) comparable to Pt/C (E1/2 = 0.85 V vs RHE), and the assembled zinc-air (Zn-air) battery displays an excellent durability with the open circuit voltage (1.23 V) decaying only by ca. 4.2% in 80 h at 20 mA cm−2. For CO2RR, it also delivers an outstanding catalytic performance converting CO2 into CO with a high Faradaic efficiency (90% at −0.5 V vs RHE). Control experiments have indicated that the potential synergistic interactions between Cu (0) (from Cu NPs) and Cu-Nx sites have promoting effects on both ORR and CO2RR. A composite Cu@Cu–N–C catalyst with Cu(0)-Cu(II)-Nx active sites exhibits an impressive catalytic bifunction towards oxygen reduction reaction (ORR) and carbon dioxide reduction (CO2RR). [Display omitted] •A hollow Cu@Cu–N–C carbon material is pyrolyzed from Cu(OH)2@ ZIF-8 precursor.•Cu@Cu–N–C carbon material exhibits a catalytic bifunction towards ORR and CO2RR.•A synergistic effect between Cu NPs and Cu-Nx has been revealed for ORR and CO2RR.