Construction of CoP/Co2P Coexisting Bifunctional Self-Supporting Electrocatalysts for High-Efficiency Oxygen Evolution and Hydrogen Evolution

Linyi Zhang; Yu Chen; Guangsheng Liu; Zhen Li; Song Liu; Santosh K Tiwari; Oluwafunmilola Ola; Bingyan Pang; Nannan Wang; Yanqiu Zhu

doi:10.1021/acsomega.2c00123

Construction of CoP/Co₂P Coexisting Bifunctional Self-Supporting Electrocatalysts for High-Efficiency Oxygen Evolution and Hydrogen Evolution

ACS Omega. 2022 Apr 4;7(15):12846-12855. doi: 10.1021/acsomega.2c00123. eCollection 2022 Apr 19.

Authors

Linyi Zhang¹, Yu Chen², Guangsheng Liu¹, Zhen Li¹, Song Liu¹, Santosh K Tiwari¹, Oluwafunmilola Ola³, Bingyan Pang¹, Nannan Wang¹, Yanqiu Zhu^{1

2}

Affiliations

¹ Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, School of Resources, Environment and Materials, Guangxi Institute Fullerene Technology (GIFT), Guangxi University, Nanning 530004, China.
² College of Engineering, Department of Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, U.K.
³ Advanced Materials Group, Faculty of Engineering, The University of Nottingham, Nottingham NG7 2RD, U.K.

Abstract

Development of a low cost, high activity, and stable nonprecious metal bifunctional catalyst for electrocatalytic water cracking is a hot topic and big challenge. In this paper, we prepared a nitrogen-doped carbon nanotube (NCNT)-enhanced three-dimensional self-supported electrocatalyst with CoP and Co₂P coexistence by a two-step strategy of high-temperature carbonization and low-temperature phosphorylation. Furthermore, the induced three-dimensional carbon network skeleton facilitates rapid charge transfer. In addition, the active sites of the carbon foam (CF) are greatly increased by the construction of hollow structures. As a bifunctional electrocatalyst, CoP/Co₂P/NCNT@CF exhibited excellent catalytic activity for both hydrogen evolution reaction and oxygen evolution reaction in alkaline media, requiring low overpotentials of 133 and 289 mV to obtain a current density of 10 mA cm^-2, respectively. Additionally, the synthesized catalysts also exhibit good long-term stability, maintaining high catalytic activity after 20 h of continuous operation. We also confirmed the main driving force to improve the electron transfer between the heterostructures of Co and P by XPS spectra. The excellent electrocatalytic performance can be attributed to the close synergy between the highly active CoP/Co₂P/NCNT and CF. This study provides a new strategy for the design of highly active bifunctional self-supporting electrocatalysts.