Title

Nickel Selenide As a High-Efficiency Catalyst for Oxygen Evolution Reaction

Abstract

A metal-rich form of Ni-selenide, nickel subselenide, Ni3Se2 has been investigated as a potential oxygen evolution electrocatalyst under alkaline conditions for the first time. The Ni3Se2 phase has a structure similar to the sulfur mineral heazlewoodite, which contains metal-metal bonding. The electrocatalytic activities of Ni3Se2 towards OER were seen to be at par with or even superior to the transition metal oxide based electrocatalyst in terms of onset overpotential for O2 evolution as well as overpotential to reach a current density of 10 mA cm-2 (observed at 290 mV). The electrocatalytic Ni3Se2 films were grown by electrodeposition on conducting substrates and the deposition parameters including the pH of the electrolytic bath, deposition potential, and substrate composition were seen to have some influence on the catalytic activity. So far, Ni3Se2 films deposited on the Au-coated Si substrate was seen to have the lowest overpotential. Annealing of the as-deposited electrocatalytic films in an inert atmosphere, enhanced their catalytic efficiencies by decreasing the overpotential (@10 mA cm-2) as well as increasing the current density. The structure and morphology of these films has been characterized by powder X-ray diffraction, scanning and transmission electron microscopy, Raman, and X-ray photoelectron spectroscopy. Catalytic activities were investigated through detailed electrochemical studies under alkaline conditions, including linear sweep voltammetry, chronoamperometric studies at constant potential, electrochemical surface area determination and calculation of the Tafel slope. The Faradaic efficiency of this catalyst has been estimated by reducing the evolved O2 in a RRDE set-up which also confirmed that the evolved gas was indeed O2. In addition to low overpotentials, these Ni3Se2 electrodeposited films were seen to be exceptionally stable under conditions of continuous O2 evolution for an extended period (42 h).

Department(s)

Chemistry

Keywords and Phrases

Alkalinity; Catalyst activity; Catalysts; Chemical detection; Conductive films; Deposition; Efficiency; Electrocatalysts; Electrodeposition; Electrodes; Gold; Gold deposits; High resolution transmission electron microscopy; Metals; Nickel; Scanning electron microscopy; Substrates; Transition metal compounds; Transition metals; Transmission electron microscopy; X ray diffraction; Chronoamperometric study; Electrocatalytic activity; Electrochemical surface area; High-efficiency catalysts; Linear sweep voltammetry; Oxygen evolution reaction; Scanning and transmission electron microscopy; Structure and morphology

International Standard Serial Number (ISSN)

1754-5692

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2016 Royal Society of Chemistry, All rights reserved.

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