Chinese Journal of Catalysis

Chinese Journal of Catalysis ›› 2021, Vol. 42 ›› Issue (7): 1205-1215.DOI: 10.1016/S1872-2067(20)63748-2

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New strategy of S,N co-doping of conductive-copolymer-derived carbon nanotubes to effectively improve the dispersion of PtCu nanocrystals for boosting the electrocatalytic oxidation of methanol

Jingping Zhonga,d,†, Kexin Huanga,†, Wentao Xua, Huaguo Tanga, Muhammad Waqasa, Youjun Fana,*(), Ruixiang Wanga, Wei Chena,#(), Yixuan Wangb,c,$()   

  1. aGuangxi Key Laboratory of Low Carbon Energy Materials, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, Guangxi, China
    bDepartment of Chemistry and Forensic Science, Albany State University, Albany, GA 31705, USA
    cProvincial Key Laboratory of Molecular Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250010, Shandong, China
    dGuangxi Engineering Center in Biomedical Material for Tissue and Organ Regeneration, Life Sciences Institute, Guangxi Medical University, Nanning 530021, Guangxi, China
  • Received:2020-10-22 Accepted:2020-11-27 Online:2021-07-18 Published:2020-12-10
  • Contact: Youjun Fan,Wei Chen,Yixuan Wang
  • About author:$ E-mail: yixuan.wamg@asurams.edu
    # E-mail: weichen@mailbox.gxnu.edu.cn;
    * E-mail: youjunfan@mailbox.gxnu.edu.cn;

    † These authors contributed equally to this work.

  • Supported by:
    National Natural Science Foundation of China(21463007);Natural Science Foundation of Guangxi Province(2017GXNSFDA198031);Natural Science Foundation of Guangxi Province(2019GXNSFGA245003)

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Abstract:

Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance. However, the guidelines for designing hybrid materials with advantageous structures and the fundamental understanding of their electrocatalytic mechanisms remain unclear. Herein, superfine Pt and PtCu nanoparticles supported by novel S,N-co-doped multi-walled CNT (MWCNTs) were prepared through the innovative pyrolysis of a poly(3,4-ethylenedioxythiophene)/polyaniline copolymer as a source of S and N. The uniform wrapping of the copolymer around the MWCNTs provides a high density of evenly distributed defects on the surface after the pyrolysis treatment, facilitating the uniform distribution of ultrafine Pt and PtCu nanoparticles. Remarkably, the Pt1Cu2/SN-MWCNTs show an obviously larger electroactive surface area and higher mass activity, stability, and CO poisoning resistance in methanol oxidation compared to Pt/SN-MWCNTs, Pt/S-MWCNTs, Pt/N-MWCNTs, and commercial Pt/C. Density functional theory studies confirm that the co-doping of S and N considerably deforms the CNTs and polarizes the adjacent C atoms. Consequently, both the adsorption of Pt1Cu2 onto the SN-MWCNTs and the subsequent adsorption of methanol are enhanced; in addition, the catalytic activity of Pt1Cu2/SN-MWCNTs for methanol oxidation is thermodynamically and kinetically more favorable than that of its CNT and N-CNT counterparts. This work provides a novel method to fabricate high-performance fuel cell electrocatalysts with highly dispersed and stable Pt-based nanoparticles on a carbon substrate.

Key words: Methanol oxidation, Conductive copolymers, Dual-doped carbon nanotubes, Pt-based nanoparticles, DFT calculation