Synergistic coupling of heterostructured porous CoP nanosheets with P doped NiO for highly efficient overall alkaline water splitting

Fei Nie; Zhaohui Yang; Xiaoping Dai; Ziteng Ren; Xueli Yin; Yonghao Gan; Baoqiang Wu; Yihua Cao; Run Cai; Xin Zhang

doi:10.1016/j.jcis.2022.04.056

Synergistic coupling of heterostructured porous CoP nanosheets with P doped NiO for highly efficient overall alkaline water splitting

J Colloid Interface Sci. 2022 Sep:621:213-221. doi: 10.1016/j.jcis.2022.04.056. Epub 2022 Apr 12.

Authors

Fei Nie¹, Zhaohui Yang¹, Xiaoping Dai², Ziteng Ren¹, Xueli Yin¹, Yonghao Gan¹, Baoqiang Wu¹, Yihua Cao¹, Run Cai¹, Xin Zhang¹

Affiliations

¹ State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum, Beijing 102249, China.
² State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum, Beijing 102249, China. Electronic address: daixp@cup.edu.cn.

PMID: 35461136
DOI: 10.1016/j.jcis.2022.04.056

Abstract

Exploring non-noble metal materials as bifunctional catalysts for water electrolysis is of great significance for the development and utilization of hydrogen energy. Herein, a flower branch-leaf shaped phosphide/oxide heterogeneous electrocatalyst located on Ni foam (CoP/P-NiO/NF) was developed through hydrothermal and phosphorization strategy. Benefiting from the strong ability to dissociate H₂O molecules on P-NiO and the suitable adsorption of intermediate H species on CoP, the optimal CoP/P-NiO/NF exhibited outstanding performance with low overpotentials of 52 mV at current density of 10 mA cm^-2, smaller Tafel slopes of 73.6 mV dec^-1 for hydrogen evolution reaction (HER). Meanwhile, CoP/P-NiO/NF indicated 265 mV at 100 mA cm^-2 with Tafel slope of 101.8 mV dec^-1 for oxygen evolution reaction (OER) due to the optimal redistribution of electrons among Ni²⁺, Co²⁺ and Co³⁺ for favorable adsorption/desorption of oxygen-intermediates. Both HER and OER shown robust stability during 32 h without decline. The corresponding two-electrode system for overall alkaline water splitting required a low voltage of 1.6 V at 100 mA cm^-2 with long stability (20 h) which is far lower than that on RuO₂-Pt/C and many other reported non-noble metal electrocatalysts. This work demonstrates that the synergistic effect and morphology engineering play vital roles in the enhanced electrocatalytic performance.

Keywords: Bifunctional electrocatalysts; Morphology engineering; Overall alkaline water splitting; Porous phosphide/oxide heterogeneous nanosheets; Synergistic effect.