Interface Engineering of NixSy@MnOxHy Nanorods to Efficiently Enhance Overall-Water-Splitting Activity and Stability

Pan Wang; Yuanzhi Luo; Gaixia Zhang; Zhangsen Chen; Hariprasad Ranganathan; Shuhui Sun; Zhicong Shi

doi:10.1007/s40820-022-00860-2

Interface Engineering of Ni_xS_y@MnO_xH_y Nanorods to Efficiently Enhance Overall-Water-Splitting Activity and Stability

Nanomicro Lett. 2022 May 3;14(1):120. doi: 10.1007/s40820-022-00860-2.

Authors

Pan Wang^{1

2

3}, Yuanzhi Luo¹, Gaixia Zhang⁴, Zhangsen Chen², Hariprasad Ranganathan², Shuhui Sun⁵, Zhicong Shi⁶

Affiliations

¹ Institute of Batteries, School of Materials and Energy, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China.
² Énergie Matériaux Télécommunications Research Centre, Institut National de La Recherche Scientifique (INRS), Varennes, Québec, J3X 1P7, Canada.
³ The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510641, People's Republic of China.
⁴ Énergie Matériaux Télécommunications Research Centre, Institut National de La Recherche Scientifique (INRS), Varennes, Québec, J3X 1P7, Canada. gaixia.zhang@inrs.ca.
⁵ Énergie Matériaux Télécommunications Research Centre, Institut National de La Recherche Scientifique (INRS), Varennes, Québec, J3X 1P7, Canada. shuhui.sun@inrs.ca.
⁶ Institute of Batteries, School of Materials and Energy, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China. zhicong@gdut.edu.cn.

Abstract

Three-dimensional (3D) core-shell heterostructured Ni_xS_y@MnO_xH_y nanorods grown on nickel foam (Ni_xS_y@MnO_xH_y/NF) were successfully fabricated via a simple hydrothermal reaction and a subsequent electrodeposition process. The fabricated Ni_xS_y@MnO_xH_y/NF shows outstanding bifunctional activity and stability for hydrogen evolution reaction and oxygen evolution reaction, as well as overall-water-splitting performance. The main origins are the interface engineering of Ni_xS_y@MnO_xH_y, the shell-protection characteristic of MnO_xH_y, and the 3D open nanorod structure, which remarkably endow the electrocatalyst with high activity and stability. Exploring highly active and stable transition metal-based bifunctional electrocatalysts has recently attracted extensive research interests for achieving high inherent activity, abundant exposed active sites, rapid mass transfer, and strong structure stability for overall water splitting. Herein, an interface engineering coupled with shell-protection strategy was applied to construct three-dimensional (3D) core-shell Ni_xS_y@MnO_xH_y heterostructure nanorods grown on nickel foam (Ni_xS_y@MnO_xH_y/NF) as a bifunctional electrocatalyst. Ni_xS_y@MnO_xH_y/NF was synthesized via a facile hydrothermal reaction followed by an electrodeposition process. The X-ray absorption fine structure spectra reveal that abundant Mn-S bonds connect the heterostructure interfaces of Ni_xS_y@MnO_xH_y, leading to a strong electronic interaction, which improves the intrinsic activities of hydrogen evolution reaction and oxygen evolution reaction (OER). Besides, as an efficient protective shell, the MnO_xH_y dramatically inhibits the electrochemical corrosion of the electrocatalyst at high current densities, which remarkably enhances the stability at high potentials. Furthermore, the 3D nanorod structure not only exposes enriched active sites, but also accelerates the electrolyte diffusion and bubble desorption. Therefore, Ni_xS_y@MnO_xH_y/NF exhibits exceptional bifunctional activity and stability for overall water splitting, with low overpotentials of 326 and 356 mV for OER at 100 and 500 mA cm^-2, respectively, along with high stability of 150 h at 100 mA cm^-2. Furthermore, for overall water splitting, it presents a low cell voltage of 1.529 V at 10 mA cm^-2, accompanied by excellent stability at 100 mA cm^-2 for 100 h. This work sheds a light on exploring highly active and stable bifunctional electrocatalysts by the interface engineering coupled with shell-protection strategy.

Keywords: Bifunctional; Interface engineering; Manganese compound; Nickel sulfides; Protective shell; Water splitting.