Accelerating the water splitting kinetics of CoP microcubes anchored on a graphene electrocatalyst by Mn incorporation

Xun Xu; Hanfeng Liang; Guisheng Tang; Yingling Hong; Yaqiang Xie; Zhengbing Qi; Binbin Xu; Zhoucheng Wang

doi:10.1039/c8na00261d

Accelerating the water splitting kinetics of CoP microcubes anchored on a graphene electrocatalyst by Mn incorporation

Nanoscale Adv. 2018 Nov 21;1(1):177-183. doi: 10.1039/c8na00261d. eCollection 2019 Jan 15.

Authors

Xun Xu^{1

2}, Hanfeng Liang³, Guisheng Tang¹, Yingling Hong¹, Yaqiang Xie¹, Zhengbing Qi⁴, Binbin Xu¹, Zhoucheng Wang¹

Affiliations

¹ College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 China zcwang@xmu.edu.cn.
² School of Materials and Mechanical & Electrical Engineering, Jiangxi Science and Technology Normal University Nanchang 330013 China.
³ Materials Science and Engineering, King Abdullah University of Science and Technology Thuwal 23955 Saudi Arabia hanfeng.liang@kaust.edu.sa.
⁴ College of Materials Science and Engineering, Xiamen University of Technology Xiamen 361024 China.

Abstract

CoP is considered as an efficient electrocatalyst for the hydrogen evolution reaction (HER) in acidic electrolytes but its performance in alkaline solutions is generally poor because of its slow reaction kinetics, which further limits its application in overall water splitting. Herein, we demonstrate a strategy to greatly accelerate its HER and OER kinetics in alkaline solutions through Mn incorporation. Ternary Mn _x Co_1-x P microcubes with a tunable Mn/Co ratio strongly anchored on rGO were synthesized using Prussian blue analogues as precursors. The synergy between the high activity of Mn _x Co_1-x P microcubes and the good conductivity of rGO leads to the superior performance of the hybrid toward water splitting in 1 M KOH. The optimized Mn_0.6Co_0.4P-rGO electrocatalyst shows high activity and stability towards both the HER and OER with low overpotentials of 54 and 250 mV at 10 mA cm^-2, respectively. Furthermore, the water electrolyzer using Mn_0.6Co_0.4P-rGO as both the cathode and anode only requires a cell voltage as low as 1.55 V to reach a current density of 10 mA cm^-2, making Mn_0.6Co_0.4P-rGO a competitive and cost-effective electrocatalyst for water splitting.