Efficient electroreduction of CO2 to CO by Ag-decorated S-doped g-C3N4/CNT nanocomposites at industrial scale current density. (March 2020)

• Record Type: Journal Article
• Authors: Chen, J.; Wang, Z.; Lee, H.; Mao, J.; Grimes, C.A.; Liu, C.; Zhang, M.; Lu, Z.; Chen, Y.; Feng, S.-P.
• Is Part Of: Materials today physics. Volume 12(2019)
• Publication Date: 2020-03
• Subjects: CO2 reduction -- Electrocatalyst -- Nanocomposites -- Flow cell; Materials science -- Periodicals; Physics -- Periodicals; Electronic journals; 530.41
• DOI: 10.1016/j.mtphys.2019.100176
• Languages: English
• ISSNs: 2542-5293

Abstract

Abstract: In recent years, the application of graphitic carbon nitride (g-C3 N4 ) for electrochemical CO2 reduction reaction (eCO2 RR) has aroused strong interest. However, this material is still facing severe activity issue towards eCO2 RR 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–C3 N4 /CNT) for efficient eCO2 RR to carbon monoxide (CO). The resulting Ag–S–C3 N4 /CNT catalyst exhibits a notable performance in eCO2 RR, yielding a high current density of −21.3 mA/cm 2 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 eCO2 RR, showing a current density larger than 200 mA/cm 2 and the Faradaic efficiency of CO over 80% in a wide potential window, delivering the best eCO2 RR performance among the C3 N4 -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 eCO2 RR to CO but also leads to new insights on the application of C3 N4 -based composite materials in electrocatalytic processes. Graphical abstract: Ag-decorated sulfur-doped C3 N4 /CNT nanocomposites were synthesized as a highly active and selective eCO2 RR catalyst. The resulting nanocomposites exhibit excellent performance in eCO2 RR to CO, yielding a high current density of −21.3 mA/cm 2 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 eCO2 RR performance among C3 N4 -derivatives, with a current density larger than 200 mA/cm 2 and great CO Faradaic efficiency over 80% in a wide potential window. Image 1 Highlights: C3 N4 -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 C3 N4 -derivates. The best electrochemical CO2 reduction performance among the C3 N4 -based materials was achieved