Recent Advances in Transition Metal Phosphide Electrocatalysts for Water Splitting under Neutral pH Conditions

Considerable attention on sustainable clean energy resources has led to the development of a plethora of catalytic materials, specifically geared toward water electrolysis. Among various developed catalysts, noble-metal-based electrocatalysts have shown promising performances for oxygen and hydrogen evolution reactions (OER and HER). However, their high price and scarcity have always been roadblocks to the commercialization of the water-splitting technology. Recently, transition metal phosphides (TMP) and phosphates (TMPi) have emerged as alternative electrocatalysts for the OER and HER under neutral conditions; water splitting under a neutral conditions eco-friendly and free of the corrosion issues that are present for acidic or alkaline conditions. Herein, we present the recent progress in TMP(i) based water splitting under neutral conditions, particularly focusing on the synthetic strategies and design concepts for improved catalytic performances. Challenges and outlook for further development of these promising catalysts are also discussed.