Synthesis of MgNiO2/CoNC-Based Ternary Metallic Dual-Active Interfacial Porous Hollow Nanocages as Efficient Oxygen Reduction Reaction and Oxygen Evolution Reaction Bi-Functional Electrocatalysts

Shanshan Li,Yang Yuan,Fangfang Chang,Qing Zhang,Zhengyu Bai,Lin Yang

doi:10.3389/fmats.2020.543180

Abstract

Combining the catalytic activities of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) into one electrocatalyst is of great significance in simultaneously prompting the charge-discharge cycles of various renewable energy storage and conversion systems such as metal-air batteries. Herein we report a ternary metallic based MgNiO2/CoNC porous hollow nanocage composite, which assembled with intimate contacted MgNiO2 and Co species to form the ultrathin nanocage shells and serve as the ORR and OER active components respectively to reveal a highly bi-functional catalytic performance. The possible synergy of each seamlessly connected metallic sites renders the hybrid material with excellent ORR and OER activities, which outperform than the corresponding benchmarks. Particularly, we speculate such efficient catalytic activity might arise from the synergistic chemical coupling effects within MgNiO2/CoNC and therefore, these results reveals promising prospects in developing multi-metallic composites toward efficient electrochemical energy devices.

Highlights

Owing to increasing energy demands, renewable energy storage and conversion technologies, such as fuel cells, metal-air batteries, and water splitting, are drawing considerable attention due to their theoretically high energy densities and affordable environmental features (Lee et al, 2015; Fu et al, 2018; Zhu et al, 2019a; Hu et al (2020))
Porous MgNiO2/CoNC hollow nanocages were successfully synthesized through metal–organic frameworks (MOFs)-templated reactions, and explored as a high performance bi-functional catalyst
After a period of heating at 90°C, protons produced by the hydrolysis of Mg2+ and Ni2+ ions gradually corroded the ZIF-67 templates to release Co2+ ions, which were partially oxidized by the nitrate ions and oxygen molecules in the solvothermal system and subsequently coprecipitated with Mg2+ and Ni2+ to assemble the MgNiCo/ ZIF-67 shells (Hu et al, 2015)

Summary

Introduction

Owing to increasing energy demands, renewable energy storage and conversion technologies, such as fuel cells, metal-air batteries, and water splitting, are drawing considerable attention due to their theoretically high energy densities and affordable environmental features (Lee et al, 2015; Fu et al, 2018; Zhu et al, 2019a; Hu et al (2020)). We demonstrate an innovative approach for the general and feasible synthesis of multi-compositional MgNiO2/ CoNC porous hollow nanocages via MOF-templated reactions as a high performance bi-functional catalyst toward ORR and OER, of which some facile steps mainly involve solvothermal coating of MgNiO2 on ZIF-67 to form porous hollow nanocage structures, followed by thermal annealing in argon.

Results

Conclusion