Engineering cobalt molybdate nanosheet arrays with phosphorus-modified nickel as heterogeneous electrodes for highly-active energy-saving water splitting

Dongmei Feng; Runze Ye; Yun Tong; Xuhui Ren; Pengzuo Chen

doi:10.1016/j.jcis.2023.01.045

Engineering cobalt molybdate nanosheet arrays with phosphorus-modified nickel as heterogeneous electrodes for highly-active energy-saving water splitting

J Colloid Interface Sci. 2023 Apr 15:636:425-434. doi: 10.1016/j.jcis.2023.01.045. Epub 2023 Jan 11.

Authors

Dongmei Feng¹, Runze Ye¹, Yun Tong², Xuhui Ren¹, Pengzuo Chen³

Affiliations

¹ Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China.
² Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China. Electronic address: tongyun@mail.ustc.edu.cn.
³ Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China. Electronic address: pzchen@zstu.edu.cn.

PMID: 36641818
DOI: 10.1016/j.jcis.2023.01.045

Abstract

Electrochemical urea electrolysis has been regarded as a promising strategy to replace traditional water-splitting technology to achieve hydrogen fuel due to its cost savings and high energy efficiency. Designing efficient bifunctional electrocatalysts easily is important but still faces significant challenges. Herein, an interface engineering strategy is used to construct a hybrid material by coupling cobalt molybdate (CoMoO₄) nanosheet arrays with phosphorus-modified nickel (P-Ni) particles on copper foam (P-Ni@CoMoO₄/CF) through the hydrothermal and in-situ electrodeposition process. Benefiting from the abundant catalytic active sites, low charge transfer resistance, and synergistic coupling effect, the optimal P-Ni@CoMoO₄/CF electrocatalyst presents a superior bifunctional activity for urea oxidation reaction (UOR) and hydrogen evolution reaction (HER). In detail, a small overpotential of 125 mV and a low potential of 1.36 V is required to attain the current density of 100 mA cm^-2 for HER and UOR, respectively. In the process of urea electrolysis, the P-Ni@CoMoO₄/CF-based electrolyzer provides a current density of 100 mA cm^-2 with an overall voltage of 1.50 V, about 170 mV less than that in a traditional water electrolyzer. The high performance of P-Ni@CoMoO₄/CF outperforms many recently reported electrodes, suggesting its promising application in energy-saving hydrogen production. Our work proposes a novel idea for the rational design and exploitation of low-cost and robust bifunctional electrodes for electrocatalysis.

Keywords: Bifunctional activity; Cobalt molybdate; Energy-saving water splitting; Heterogeneous structure; Phosphorus-modified nickel.