Constructing Fe‐Co ₂ P/CeO ₂ heterostructure nanosheet arrays for attaining energy‐saving hydrogen production in seawater

Abstract

Abstract Electrolyzing seawater is a promising solution to produce hydrogen, which is hindered by low‐efficiency oxygen evolution reaction (OER) and noxious chloride chemistry. Herein, the Fe‐Co 2 P/CeO 2 heterostructure nanosheet arrays are developed to achieve energy‐saving and chlorine‐free hydrogen generation by coupling hydrogen evolution reaction (HER) with hydrazine oxidation reaction (HzOR) in seawater. The Fe‐Co 2 P/CeO 2 realizes current densities of 10 and 400 mA·cm −2 at 52 and 204 mV for HER. The anode potential is significantly decreased after replacing OER with HzOR. Theoretical calculations display that the electronic structure of Fe‐Co 2 P can be regulated after coupling CeO 2 , which lowers the water dissociation barrier and optimizes hydrogen adsorption‐free energy, thus boosting catalytic kinetics. Significantly, the hybrid seawater electrolyzer produces hydrogen at ultralow cell voltages, greatly reducing traditional water electrolysis voltages and avoiding hazardous chlorine chemistry. This study provides an avenue to exploit advanced catalysts for acquiring hydrogen with energy‐efficiency and chlorine‐free from abundant ocean.