Mott–Schottky Barrier Enabling High‐Performance Hydrazine‐Assisted Hydrogen Generation at Ampere‐Level Current Densities

Abstract

AbstractLocal electron density manipulation can optimize the adsorption and desorption nature of catalysts leading to enhanced catalytic activity for water oxidation. Construction a Mott–Schottky barrier allows the electron transition in catalysts because of their different Fermi levels. Herein, a Pt@NiFc‐MOF Mott–Schottky heterojunction is constructed, in which electrons are transferred from NiFc‐MOF to Pt as triggered by the formed built‐in electric field at the interface. The as‐prepared Pt@NiFc‐MOF reveals exceptional performance toward the hydrazine oxidation reaction (HzOR), hydrogen evolution reaction (HER), and overall hydrazine splitting (OHzS) at ampere‐level current densities. The advanced nature of the configured Mott–Schottky heterojunction can also be further evidenced from a concept direct liquid N2H4/H2O2 fuel cell (Pt@NiFc‐MOF//Pt Net), yielding a maximum power density of 415.2 mW cm‒2 at 80°C and can work stably for 190 h at 500 mA cm‒2 (at 25°C). One more function of Pt@NiFc‐MOF is clarified as well, that is it can purify hydrazine‐rich wastewater from 718 to 6 ppb (less than the U.S. Environmental Protection Agency of 10 ppb) in 120 min at 500 mA cm‒2. This work represents a breakthrough in interface engineering of metal–organic frameworks (MOFs) toward industry‐level hydrogen generation and its beyond.