Efficient electroreduction of CO2 to CO by Ag-decorated S-doped g-C3N4/CNT nanocomposites at industrial scale current density

• Published in: Materials today physics Vol. 12; p. 100176
• Main Authors: Chen, J., Wang, Z., Lee, H., Mao, J., Grimes, C.A., Liu, C., Zhang, M., Lu, Z., Chen, Y., Feng, S.-P.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2020
• Subjects: CO2 reduction; Electrocatalyst; Flow cell; Nanocomposites; Electrocatalyst; Nanocomposites; CO2 reduction; Flow cell
• ISSN: 2542-5293; 2542-5293
• DOI: 10.1016/j.mtphys.2019.100176

In recent years, the application of graphitic carbon nitride (g-C3N4) for electrochemical CO2 reduction reaction (eCO2RR) has aroused strong interest. However, this material is still facing severe activity issue towards eCO2RR so far, and studies on its catalytic mechanism have not been sufficiently implemented either. Herein, we report an Ag-decorated sulfur-doped graphitic carbon nitride/carbon nanotube nanocomposites (Ag–S–C3N4/CNT) for efficient eCO2RR to carbon monoxide (CO). The resulting Ag–S–C3N4/CNT catalyst exhibits a notable performance in eCO2RR, yielding a high current density of −21.3 mA/cm2 at −0.77 VRHE and maximum CO Faradaic efficiency over 90% in H-type cell. Strikingly, when combining with flow cell configuration, the fabricated nanocomposites permit an industrial scale and cost-effective eCO2RR, showing a current density larger than 200 mA/cm2 and the Faradaic efficiency of CO over 80% in a wide potential window, delivering the best eCO2RR performance among the C3N4-derivatives. Moreover, the catalytic mechanism of this nanocomposite has been further explored through density functional theory (DFT) and electrochemical methods carefully. Our work not only sheds light on industrial scale eCO2RR to CO but also leads to new insights on the application of C3N4-based composite materials in electrocatalytic processes. Ag-decorated sulfur-doped C3N4/CNT nanocomposites were synthesized as a highly active and selective eCO2RR catalyst. The resulting nanocomposites exhibit excellent performance in eCO2RR to CO, yielding a high current density of −21.3 mA/cm2 at −0.77 VRHE and maximum CO Faradaic efficiency over 90% in H-cell. In addition, when combining with flow cell configuration, the obtained catalyst delivers the best eCO2RR performance among C3N4-derivatives, with a current density larger than 200 mA/cm2 and great CO Faradaic efficiency over 80% in a wide potential window. [Display omitted] •C3N4-based nanomaterial has been developed as an efficient catalyst towards electrochemical CO2 reduction reaction.•Systematic studies were carried out to understand the catalytic mechanism of the C3N4-derivates.•The best electrochemical CO2 reduction performance among the C3N4-based materials was achieved