Coupling Hierarchical Ultrathin Co Nanosheets With N-Doped Carbon Plate as High-Efficiency Oxygen Evolution Electrocatalysts

Yue Wang,Dongmei Sun,Qixing Zhou,Meng Li,Yawen Tang,Xingyuan Zhang,Qin Wang

doi:10.3389/fnano.2021.659865

Yue Wang, Dongmei Sun + Show 5 more

Open Access

https://doi.org/10.3389/fnano.2021.659865

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Abstract

The rational design of cost-effective and highly efficient catalysts for the oxygen evolution reaction (OER) is vastly desirable for advanced renewable energy conversion and storage systems. Tailoring the composition and architecture of electrocatalysts is a reliable approach for improving their catalytic performance. Herein, we developed hierarchical ultra-thin Co nanosheets coupled with N-doped carbon plate (Co-NS@NCP) as an efficient OER catalyst through a feasible and easily scalable NaCl template method. The rapid dissolution-recrystallization-carbonization synthesis process allows Co nanosheets to self-assemble into plenty of secondary building units and to distribute uniformly on N-doped carbon plate. Benefitting from the vertically aligned Co nanosheet arrays and hierarchical architecture, the obtained Co-NS@NCP possess an extremely high specific surface area up to 446.49 m2 g−1, which provides sufficient exposed active sites, excellent structure stability, and multidimensional mass transfer channels. Thus, the Co-NS@NCP affords remarkable electrocatalytic performance for OER in an alkaline medium with a low overpotential of only 278 mV at 10 mA cm−2, a small Tafel slope, as well as robust electrocatalytic stability for long-term electrolysis operation. The present findings here emphasize a rational and promising perspective for designing high-efficiency non-precious electrocatalysts for the OER process and sustainable energy storage and conversion system.

Highlights

Urged by the ever-increasing consumption of fossil fuels and environmental pollution problems, numerous efforts have been put to design new renewable energy materials and technologies (Liu et al, 2020; Zhang X. et al, 2020; Zheng et al, 2020)
The Co2+- histidine@NaCl complexes were first synthesized by the rapid dissolution and recrystallization of Co(NO3)2·6H2O, histidine, and excessive NaCl precursors
Excessive NaCl was chosen as a hard-template which provides a stable 2D platform for the formation and growth of Co nanosheets and carbon plate (Fu et al, 2017b; Huan et al, 2019)

Summary

INTRODUCTION

Urged by the ever-increasing consumption of fossil fuels and environmental pollution problems, numerous efforts have been put to design new renewable energy materials and technologies (Liu et al, 2020; Zhang X. et al, 2020; Zheng et al, 2020). The construction of special nanostructures (e.g., hollow structure, hierarchical structure, nanoarray architectures, etc.) can endow the electrocatalysts with a higher specific surface area to expose more active sites and possess more mass transport channels to enhance the rate of reaction (Fu et al, 2017a; Cheng et al, 2019; Wang S. et al, 2019; Zhang, C.-L. et al, 2020). The design and construction of self-supported hierarchically Co-based catalysts on carbon substrate should be able to deliver a satisfactory catalytic performance with improved catalytic activity and robust stability (Yang et al, 2019c). The hierarchical and porous structure of the Co-NS@NCP provides a high specific surface area (446.49 cm g−1), abundant exposed active sites, excellent structure stability, and multidimensional mass transfer channels. The resulting Co-NS@NCP catalyst displays an excellent OER performance with a low overpotential at 10 mA cm−2 (only 278 mV), a small Tafel slope, as well as steady electrocatalytic stability, which significantly superior to that of commercial RuO2

RESULTS AND DISCUSSION

CONCLUSION

DATA AVAILABILITY STATEMENT