Hierarchical Mesoporous NiO/MnO2@PANI Core-Shell Microspheres, Highly Efficient and Stable Bifunctional Electrocatalysts for Oxygen Evolution and Reduction Reactions

Junkai He; Mingchao Wang; Wenbo Wang; Ran Miao; Wei Zhong; Sheng-Yu Chen; Shannon Poges; Tahereh Jafari; Wenqiao Song; Jiachen Liu; Steven L Suib

doi:10.1021/acsami.7b07383

Hierarchical Mesoporous NiO/MnO₂@PANI Core-Shell Microspheres, Highly Efficient and Stable Bifunctional Electrocatalysts for Oxygen Evolution and Reduction Reactions

ACS Appl Mater Interfaces. 2017 Dec 13;9(49):42676-42687. doi: 10.1021/acsami.7b07383. Epub 2017 Dec 4.

Authors

Junkai He¹, Mingchao Wang^{1

2}, Wenbo Wang^{1

3}, Ran Miao⁴, Wei Zhong¹, Sheng-Yu Chen⁴, Shannon Poges⁴, Tahereh Jafari¹, Wenqiao Song⁴, Jiachen Liu², Steven L Suib^{1

4}

Affiliations

¹ Institute of Materials Science, University of Connecticut , Storrs, Connecticut 06269-3136, United States.
² Key Lab of Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University , Tianjin 300072, P. R. China.
³ State Key Laboratory of Solid Lubrication, Center of Eco-materials and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, P. R. China.
⁴ Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269-3060, United States.

PMID: 29161503
DOI: 10.1021/acsami.7b07383

Abstract

We report on the new facile synthesis of mesoporous NiO/MnO₂ in one step by modifying inverse micelle templated UCT (University of Connecticut) methods. The catalyst shows excellent electrocatalytic activity and stability for both the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) in alkaline media after further coating with polyaniline (PANI). For electrochemical performance, the optimized catalyst exhibits a potential gap, ΔE, of 0.75 V to achieve a current of 10 mA cm^-2 for the OER and -3 mA cm^-2 for the ORR in 0.1 M KOH solution. Extensive characterization methods were applied to investigate the structure-property of the catalyst for correlations with activity (e.g., XRD, BET, SEM, HRTEM, FIB-TEM, XPS, TGA, and Raman). The high electrocatalytic activity of the catalyst closely relates to the good electrical conductivity of PANI, accessible mesoporous structure, high surface area, as well as the synergistic effect of the specific core-shell structure. This work opens a new avenue for the rational design of core-shell structure catalysts for energy conversion and storage applications.

Keywords: OER; ORR; core−shell; mesoporous; polyaniline.