Atomically Confined Ru Sites in Octahedral Co3O4 for High‐Efficiency Hydrazine Oxidation

Abstract

AbstractHydrazine‐assisted water electrolyzer is a promising energy‐efficient alternative to conventional water electrolyzer, offering an appealing path for sustainable hydrogen (H2) production with reduced energy consumption. However, such electrolyzer is presently impeded by lacking an efficient catalyst to accelerate the kinetics of pivotal half‐reaction, that is, hydrazine oxidation reaction (HzOR). Herein, a ruthenium (Ru) single‐atom on an octahedral cobalt oxide (Co3O4) substrate (Ru‐Co3O4) catalyst, guided by theoretical calculations is developed. Those lattice‐confined Ru sites within octahedral structure of spinel Co3O4 effectively lower the energy barrier required for the formation of N2H2* intermediate and desorption of H* species in HzOR. As a result, the Ru‐Co3O4 catalyst achieves superior HzOR performance with a low potential of −0.024 V versus (vs.)reversible hydrogen electrode (RHE) at 100 mA cm−2 and remarkable stability for over 200 h at 200 mA cm−2. Importantly, a modular H2 production achieves an output of 0.48 kWh electricity per m3 H2 by decoupling and pairing the HzOR and hydrogen evolution reaction (HER) half‐reaction with a Zinc (Zn) redox reservoir. The work represents a significant advancement in the field, offering substantial flexibility for on‐demand H2 production and energy output.