Nanostructured Ternary Nickel‐Based Mixed Anionic (Telluro)‐Selenide as a Superior Catalyst for Oxygen Evolution Reaction

Abstract

Electrochemical water splitting is among the most significant and attractive clean hydrogen generation technology. Hydrogen is considered to be an ideal renewable energy source to substitute conventional fossil fuels owing to its zero-carbon emission, intense energy density, and the ability to utilize periodic renewable energy such as wind and solar energy. [1] However, due to the high energy requirement for water oxidation reaction, practical water electrolyzers operate at a much higher voltage (1.8-2.0 V) relative to the theoretical water splitting voltage of 1.23 V, leading to a large overpotential. [2] The use of efficient electrocatalysts in anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER) can effectively decrease the overpotential and improve the sluggish kinetics of HER/OER and therefore enhance the energy efficiency of the process. [3] To date, the state-of-the-art electrocatalysts for HER are mostly Pt-based materials, [4,5] whereas the oxides of precious metals such as Ru or Ir are used as electrocatalysts for OER. [6] These precious metals, however, are scarce and expensive, limiting their widespread usage. Over the last several decades, it has become apparent that implementing large-scale water electrolysis will require the development of high-efficiency electrocatalysts, preferably composed of earth-abundant nonprecious elements. Extensive research into designing such new electrocatalysts from earthabundant elements has led to a class of catalyst compositions that exceed the present capabilities. Apart from enhanced performance, these novel compositions also broaden the knowledge and understanding of the factors that determine catalytic activity in order to customize catalyst surfaces atom by atom. [7] The electrocatalytic properties of any material are primarily influenced by its electronic structure, which depends on the central metal atom as well as the coordinating ligands. Hence, the main goal is to design catalysts through a proper understanding of structure-property correlation by varying the composition and physical structure of materials and understanding its effect on catalytic efficiency. Considerable attempts have been made to design efficient electrocatalysts for OER and HER comprising earth-abundant elements. Appreciable progress has been made over the last few years in designing highly active OER catalysts based on metal phosphate, [8][9][10] oxides, [11] chalcogenides, [12][13][14]