Interfacial Engineering of Bimetallic Carbide and Cobalt Encapsulated in Nitrogen‐Doped Carbon Nanotubes for Electrocatalytic Oxygen Reduction

• Published in: ChemSusChem 2020-10, Vol.13 (20), p.5539-5548
• Main Authors: Wang, Kun, Lu, Zhenjiang, Li, Yizhao, Wang, Shiqiang, Cao, Yali
• Format: Article
• Language: English
• Subjects: Adsorption; Bimetals; Carbides; Carbon; Carbon nanotubes; Charge transport; Cobalt; Electrical resistivity; electrocatalysis; Electrocatalysts; Electronic properties; Encapsulation; Heterojunctions; Heterostructures; Ion exchange; Nanoparticles; Nitrogen; Oxidation; oxygen reduction reaction; Oxygen reduction reactions; thermolysis; Transition metals
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.202001619

Heterojunction engineering is a fundamental strategy to develop efficient electrocatalysts for the oxygen reduction reaction by tuning electronic properties through interfacial cooperation. In this study, a heterojunction electrocatalyst consisting of bimetallic carbide Co3ZnC and cobalt encapsulated within N‐doped carbon nanotubes (Co3ZnC/Co@NCNTs) is synthesized by a facile two‐step ion exchange‐thermolysis pathway. Co3ZnC/Co@NCNTs effectively promotes interfacial charge transport between the different components with optimizes adsorption and desorption of intermediate products at the heterointerface. In situ‐grown N‐doped carbon nanotubes (NCNTs) not only improve the electrical conductivity but also suppress the oxidation of transition metal nanoparticles in alkaline media. Moreover, the abundant nitrogen types (pyridinic N, Co−Nx, and graphitic nitrogen) in the carbon skeleton provide more active sites for oxygen adsorption. Benefitting from this optimized structure, Co3ZnC/Co@NCNTs hybrid not only demonstrates excellent oxygen reduction activity, with a half‐wave potential of 0.83 V and fast mass transport with limited current density of 6.23 mA cm−2, but also exhibits superior stability and methanol tolerance, which surpass those of commercial Pt/C catalysts. This work provides an effective heterostructure for interfacial electronic modulation to improve electrocatalytic performance. Two steps ahead: A heterojunction electrocatalyst consisting of bimetallic carbide Co3ZnC and cobalt encapsulated within N‐doped carbon nanotubes (Co3ZnC/Co@NCNTs) is synthesized by a facile two‐step ion exchange‐thermolysis pathway. The catalyst not only demonstrates excellent oxygen reduction activity, but also exhibits superior stability and methanol tolerance.