Iron-based phosphides as electrocatalysts for the hydrogen evolution reaction: recent advances and future prospects

Electrochemical water splitting is the most promising process to produce carbon-neutral hydrogen as an energy carrier, and hydrogen evolution reaction (HER) electrocatalysts are essential to reduce the energy barrier and improve hydrogen production efficiency. This driving force necessitates the design of HER electrocatalysts with low-cost, high-abundance, high activity and stability. In this review, we systemically summarize recent publications with critical insight into the advances of iron-based phosphides as HER electrocatalysts. Various synthesis strategies corresponding to different phosphating strategies for guiding iron phosphide design are described, followed by illustrations of how to boost FeP HER catalytic performance by enriching the accessible active sites and modifying the electronic structure. Finally, we point out several challenges and prospects, which can open up opportunities to design next-generation FeP HER electrocatalysts.