Embedding Ru Single Atom Catalysts on Co3O4 for Efficient Hydrazine Oxidation and Direct Hydrazine Fuel Cells

Abstract

Inadequate hydrazine oxidation reaction (HzOR) catalyst remains an obstacle in achieving practical performance of direct hydrazine fuel cell (DHzFC). Herein, we present a Ru-Co3O4 catalyst, which is synthesized based on a cation exchange strategy through which Ru single atoms are embedded on the surface of Co3O4. Theoretical calculations confirm that Ru single atoms show a stronger hybridization with hydrazine molecules near the Fermi level and significantly lower the energy barrier required for N-containing intermediate formation, contributing to a record-low onset potential of -0.15 V vs. RHE and a working potential of -0.115 V vs. RHE at 10 mA cm-2. The assembled DHzFC using Ru-Co3O4 as the anode catalyst achieves an impressive power output of 310.7 mW cm-2. This work demonstrates a dexterous and precise electronic structure modulation of single atom catalysts using HzOR as a probe, also providing a referable flexibility for other electrocatalytic reactions and energy output devices.

Keywords: Single atom catalysts, hydrazine oxidation reaction, direct hydrazine fuel cell, cation-exchange