Ag–Ru interface for highly efficient hydrazine assisted water electrolysis

Abstract

Hydrazine assisted water electrolysis provides an attractive pathway for low-voltage hydrogen production while at the same time mitigating the hazardous hydrazine environmental pollutants. Herein we report the design and synthesis of Ru decorated Ag nanoparticles (NPs) where the Ag–Ru interfaces act as highly effective bifunctional electrocatalysts for the hydrazine oxidation reaction (HzOR) and the hydrogen evolution reaction (HER). The electrocatalysts with Ag–Ru interfaces demonstrate improved HzOR performance with lower overpotential, enhanced mass activity (MA) and highly selective oxidation of hydrazine into N₂. Density functional theory (DFT) computations reveal the Ag–Ru interfaces feature higher barrier for N–N bond cleavage and easier N₂ desorption, contributing to the electrocatalytic activity and selectivity. At the same time, improved HER performance is also observed due to the more favourable hydrogen desorption. Together, by employing the Ru decorated Ag NPs as electrocatalysts for both HzOR and HER, the hydrazine assisted water electrolyser delivers record-high performance with a current density of 100 mA cm⁻² at an ultralow cell voltage of 16 mV and a high current density of 983 ± 30 mA cm⁻² at a cell voltage of 0.45 V without any IR compensation.