Nanofibrous Ru/SnO2 heterostructure as robust bifunctional electrocatalyst for high-performance overall hydrazine splitting and Zn-hydrazine battery

Water electrolysis represents a green and efficient strategy for hydrogen (H₂) production. However, the four-electron transfer process involved in its anodic oxygen evolution reaction (OER) half-reaction restricts the H₂ generation rate. Employing hydrazine oxidation reaction (HzOR) as a substitute for OER in H₂ generation can dramatically reduce energy consumption. In this study, we have successfully fabricated a nanofibrous Ru/SnO₂ heterostructure that demonstrates exceptional performance in both hydrogen evolution reaction (HER) and HzOR. The obtained catalyst requires only a small overpotential of 39 mV for HER and an incredibly low potential of −0.076 V vs. reversible hydrogen electrode (RHE) for HzOR to generate the current density of 10 mA cm⁻². Furthermore, the two-electrode overall hydrazine splitting (OHzS) cell operates at working voltages of 0.026 V and 0.292 V for the current densities of 10 mA cm⁻¹ and 100 mA cm⁻², respectively, notably lower than the overall water splitting (OWS) process. Moreover, it delivers a H₂ yield rate of 0.40 mmol h⁻¹ at a voltage of 1.6 V, outperforming the OWS by 10 times. This study introduces a groundbreaking concept in the advancement of highly efficient bifunctional catalysts for HER and HzOR, carrying significant implications for tackling energy scarcity issues.