Stimulus of Work Function on Electron Transfer Process of Intermetallic Nickel-Antimonide Toward Bifunctional Electrocatalyst for Overall Water Splitting

Vimal Kumar Mariappan; Karthikeyan Krishnamoorthy; Parthiban Pazhamalai; Rajavarman Swaminathan; Sang-Jae Kim

doi:10.1002/smll.202402355

Stimulus of Work Function on Electron Transfer Process of Intermetallic Nickel-Antimonide Toward Bifunctional Electrocatalyst for Overall Water Splitting

Small. 2024 May 15:e2402355. doi: 10.1002/smll.202402355. Online ahead of print.

Authors

Vimal Kumar Mariappan^{1

2}, Karthikeyan Krishnamoorthy^{2

3

4}, Parthiban Pazhamalai^{2

3}, Rajavarman Swaminathan², Sang-Jae Kim^{2

3

5}

Affiliations

¹ Department of Materials Engineering, Indian Institute of Science, Printed Electronics and Nanoionics Lab, Bangalore, 560012, India.
² Nanomaterials & System Laboratory, Major of Mechatronics Engineering, Faculty of Applied Energy System, Jeju National University, Jeju, 63243, South Korea.
³ Research Institute of New Energy Industry (RINEI), Jeju National University, Jeju, 63243, South Korea.
⁴ CSIR-Advanced Materials and Processes Research Institute, Bhopal, Madhya Pradesh, 462026, India.
⁵ Nanomaterials & System Lab, Major of Mechanical System Engineering, College of Engineering, Jeju National University, Jeju, 63243, South Korea.

PMID: 38751066
DOI: 10.1002/smll.202402355

Abstract

Engineering the intermetallic nanostructures as an effective bifunctional electrocatalyst for hydrogen and oxygen evolution reactions (HER and OER) is of great interest in green hydrogen production. However, a few non-noble metals act as bifunctional electrocatalysts, exhibiting terrific HER and OER processes reported to date. Herein the intermetallic nickel-antimonide (Ni─Sb) dendritic nanostructure via cost-effective electro-co-deposition method is designed and their bifunctional electrocatalytic property toward HER and OER is unrevealed. The designed Ni─Sb delivers a superior bifunctional activity in 1 m KOH electrolyte, with a shallow overpotential of ≈119 mV at -10 mA for HER and ≈200 mV at 50 mA for OER. The mechanism behind the excellent bifunctional property of Ni─Sb is discussed via "interfacial descriptor" with the aid of Kelvin probe force microscopy (KPFM). This study reveals the rate of electrocatalytic reaction depends on the energy required for electron and proton transfer from the catalyst's surface. It is noteworthy that the assembled Ni─Sb-90 electrolyzer requires only a minuscule cell voltage of ≈1.46 V for water splitting, which is far superior to the art of commercial catalysts.

Keywords: HER; KPFM; OER; bifunctional electrocatalyst; interfacial descriptor; intermetallic nanostructures; nickel–antimonide; work function.

Abstract

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