Nickel Selenides in Electrocatalysis: Coupled Formate and Hydrogen Production Through Methanol Oxidation Reaction

The hydrogen economy, associated with electrochemical water splitting, represents a promising pathway to mitigate reliance on fossil fuels. However, the efficiency of this process is constrained by the sluggish oxygen evolution reaction (OER) at the anode, with low commercial interests of the produced oxygen. As a promising solution, OER can be replaced with the methanol oxidation reaction (MOR), which not only accelerates the hydrogen evolution reaction (HER) but also yields valuable formate as a product, depending on the nature of the anode electrocatalysts. In this context, nickel selenides have emerged as highly efficient and cost-effective electrocatalysts due to their rich compositional diversity, tunable electronic structures, and superior conductivity. Additionally, nickel selenides exist in multiple stoichiometric and nonstoichiometric phases, and also in the engineering versatility for optimizing catalytic MOR performance. This review comprehensively presents the design principles of electrocatalysts, provides a strategy for the optimization of performance, and discusses the mechanistic understanding of nickel selenide-based electrocatalysts for coupled HER and MOR systems, particularly focusing on the MOR. By bridging fundamental insights with practical applications, it additionally highlights the latest advancements in their catalytic MOR performance, offering insights into their potential for future energy and chemical applications.