Three‐Dimensional Assembly of Iron Phosphide Nanosheets: Synthesis and Enhanced Catalytic Activity for Hydrogen Evolution Reaction

Abstract Iron phosphides show promising but limited activity as hydrogen evolution reaction (HER) catalysts due to the low number of active sites and poor electroconductivity. Herein, iron phosphide nanosheets were synthesized and assembled to three‐dimensional structures for the first time via a physical‐vapor‐infiltration assisted hard template strategy. The 3D structured FeP x nanosheet assembly exhibits excellent electrocatalytic performance for hydrogen evolution reaction over a wide pH range, outperforming most of the FeP x catalysts reported to date in activity and exhibiting superior stability to the commercial Pt/C catalyst. Spectroscopic analyses and electrochemical results support that the fast electron transfer, increased active sites and expedited mass transport, due to the 3D structure of the FeP x nanosheets, boost the HER performance.