Branched CuAu nano-alloy for N₂H₄ oxidation-assisted H₂ production and nitrite detection in water solution

The H₂ production using N₂H₄ splitting (OHzS) was often constrained by the requirement for insufficient stability, distinct catalysts at the anode and cathode, and the high-cost electrocatalyst associated with confined activity. This work verified the efficacy of surfactant-free branched CuAu nano-alloy as a bifunctional electrocatalyst for H₂ production. Benefiting from its favorable electronic structure and surfactant-free surface, surfactant-free CuAu nano-alloy demonstrated a reduced over-potential compared with pure Cu, pure Au, and CuAu nano-alloy prepared by surfactant. When using branched CuAu nano-alloy as both cathodic and anodic electrodes, a cell voltage of 0.768 V was required to drive a current density of 10 mA/cm². After 2550 min of H₂ generation, the amplitude of the working potential for anodic reactions was found to be less than 0.92%. The enhanced electrocatalytic activity could be also applied to H₂O₂ and NaNO₂ sensors. The CuAu nano-alloy exhibited a 2.35-folds increase in sensitivity compared to pure Au nano-crystals in the detection of H₂O₂. Moreover, the detection of NaNO₂ in water solution has been successfully achieved. The detection range 0-175.0 mM was much wider than that of sensors in previous works.