S/N Co-Doped Hollow Carbon Particles for Oxygen Reduction Electrocatalysts Prepared by Spontaneous Polymerization at Oil-Water Interfaces.

Hiroya Abe,Shu Sokabe,Hiroshi Yabu,Tomokazu Matsue,Kohei Nozaki,Akichika Kumatani

doi:10.1021/acsomega.0c02182

Abstract

We herein report that sulfur and nitrogen co-doped hollow spherical carbon particles can be applied to oxygen reduction reaction (ORR) electrocatalysts prepared by calcination of polydopamine (PDA) hollow particles. The hollow structure of PDA was formed by auto-oxidative interfacial polymerization of dopamine at the oil and water interface of emulsion microdroplets. The PDA was used as the nitrogen source as well as a platform for sulfur-doping. The obtained sulfur and nitrogen co-doped hollow particles showed a higher catalytic activity than that of nonsulfur-doped particles and nonhollow particles. The high ORR activity of the calcined S-doped PDA hollow particles could be attributed to the combination of nitrogen and sulfur active sites and the large surface areas owing to a hollow spherical structure.

Highlights

Fuel cells and metal−air batteries have received much attention as next-generation batteries because of their high energy density and less environmental impact in terms of small emission of greenhouse effect gases.[1,2] Pt-loaded carbon (Pt/ C) has been used as a cathode of these battery devices because of its high catalytic activity for the oxygen reduction reaction (ORR).[3]
Hollow particles were obtained by auto-oxidative interfacial polymerization of dopamine at the oil and water interface of emulsion microdroplets.[21,26]
PDA and S-PDA have no hollow structures because these particles were prepared without oil-templating

Summary

Introduction

Fuel cells and metal−air batteries have received much attention as next-generation batteries because of their high energy density and less environmental impact in terms of small emission of greenhouse effect gases.[1,2] Pt-loaded carbon (Pt/ C) has been used as a cathode of these battery devices because of its high catalytic activity for the oxygen reduction reaction (ORR).[3]. As alternative materials for Pt-based catalysts, heteroatom-doped carbon materials, such as nitrogen[4−6] sulfur,[7,8] boron,[7,9] iron,[10−12] cobalt,[13,14] and so on, have been investigated through various methods. Polydopamine (PDA), which is automatically polymerized from dopamine by atmospheric oxidation, is one of the most promising materials because thin films of PDA spontaneously formed at the solid−liquid,[21−23] the oil−water, and the air− water interfaces.[24−26] PDA can be doped with heteroatoms by a metal chelate, the Michael addition reaction, and the Schiff-base reaction.[27] By calcination of heteroatomdoped PDA, heteroatom-doped carbon materials can be obtained .[28−30]

Methods

Results

Conclusion