Embedding Ru single atom catalysts on Co3O4 for efficient hydrazine oxidation and direct hydrazine fuel cells

Direct hydrazine fuel cells (DHzFCs) are promising energy conversion devices due to their high energy density and environmental friendliness. However, inefficient hydrazine oxidation (HzOR) remains a key bottleneck in achieving practical fuel cell performance. To address this challenge, precise material design and synthesis are necessary to modulate the electronic structure and maximize the utilization of active sites. 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.