Chinese Journal of Catalysis ›› 2019, Vol. 40 ›› Issue (4): 523-533.DOI: 10.1016/S1872-2067(19)63314-0

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Enhanced electrocatalytic activity for H2O2 production by the oxygen reduction reaction: Rational control of the structure and composition of multi-walled carbon nanotubes

Yi Wanga, Mi Yia, Kun Wangb, Shuqin Songb   

  1. a The Key Lab of Low-carbon Chemistry & Energy Conservation of Guangdong Province, School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, Guangdong, China;
    b School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
  • Received:2018-12-25 Revised:2019-01-18 Online:2019-04-18 Published:2019-03-14
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21576299, 21576300), Guangzhou Science and Technology Project (201607010104, 201707010079), Science and Technology Planning Project of Guangdong Province (2017A050501009), the National Key Research and Development Program of China (2016YFB0101204), Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program (2016TQ03N322), and the fundamental Research Funds for Central Universities (17lgzd14).

Abstract:

Hydrogen peroxide (H2O2) is a very useful chemical reagent, but the current industrial methods for its production suffer from serious energy consumption problems. Using high-activity and high-selectivity catalysts to electrocatalyze the oxygen reduction reaction (ORR) through a two-electron (2e-) pathway is a very promising route to produce H2O2. In this work, we obtained partially oxidized multi-walled carbon nanotubes (MWCNTs) with controlled structure and composition by oxidation with concentrated sulfate and potassium permanganate at 40℃ for 1 h (O-CNTs-40-1). The outer layers of O-CNTs-40-1 are damaged with defects and oxygen-containing functional groups, while the inner layers are maintained intact. The optimized structure and composition of the partially oxidized MWCNTs ensure that O-CNTs-40-1 possesses both a sufficient number of catalytic sites and good conductivity. The results of rotating ring disk electrode measurements reveal that, among all oxidized MWCNTs, O-CNTs-40-1 shows the greatest improvement in hydrogen peroxide selectivity (from~30% to~50%) and electron transfer number (from~3.4 to~3.0) compared to those of the raw MWCNTs. The results of electrochemical impedance spectroscopy measurements indicate that both the charge-transfer and intrinsic resistances of O-CNTs-40-1 are lower than those of the raw MWCNTs and of the other oxidized MWCNTs. Finally, direct tests of the H2O2 production confirm the greatly improved catalytic activity of O-CNTs-40-1 relative to that of the raw MWCNTs.

Key words: Hydrogen peroxide, Oxygen reduction reaction, Multi-walled carbon nanotubes, Electrocatalytic activity, Oxidation treatment