A Bi2Te3@CoNiMo composite as a high performance bifunctional catalyst for hydrogen and oxygen evolution reactions

Abstract

Hydrogen generated renewably by using solar energy has attracted increasing interest in the renewable energy research community. Hence, efficient electrocatalysts are in demand to reduce costs and energy consumption for oxygen and hydrogen evolution reaction (OER and HER) activity. Bismuth telluride (Bi₂Te₃)-based materials, as topological insulators (TIs), have been used to explore the fundamental properties of TIs in recent years, but investigation as functional materials for water splitting applications is still quite limited. In this work, electrocatalysts based on Bi₂Te₃ nanosheets have been fabricated, and the HER performance was investigated to further enhance OER electrocatalytic properties, with certain transition metals (Co, Ni, and Mo) selected to provide effective electrocatalytic sites. Therefore, the bifunctional catalyst Bi₂Te₃@CoNiMo was designed for synthesis by a solvothermal and chemical deposition route. The catalyst electrode, Bi₂Te₃@CoNiMo loaded on Ni foam, exhibits higher activity towards both the oxygen and the hydrogen evolution reactions than some traditional metallic catalysts in alkaline electrolytes. The difference in the HER and OER metrics (ΔE = 1.41 V) is comparable to the theoretical value (1.23 V), so that this reaction can be easily driven by a solar cell.