Ligand-free monophasic CuPd alloys endow boosted reaction kinetics toward energy-efficient hydrogen fuel production paired with hydrazine oxidation

Abstract

Optimizing the structure and components is a prevalent strategy for increasing electrocatalytic energy-saving H2 fuel production. One of the sustainable and efficient techniques is electrocatalytic water splitting for H2 generation, but it is still restricted by the kinetically sluggish OER. Due to the lower standard oxidation potential of −0.33 V, replacing the OER with anodic hydrazine oxidation reaction (HzOR) is an effective way to extensively reduce the use of electricity in water electrolysis. Through alloying, the semiconductor and adsorption characteristics of Cu, interlaced by Pd2+ solution on the Pd surface by pulsed laser ablation (PLA) in methanol, are selectively altered to maximize cathodic HER and anodic HzOR performance. The optimal Cu1Pd3/C ratio demonstrates outstanding HER performance with a low overpotential of 0.315 V at 10 mA cm−2, as well as an ultralow overpotential of 0.560 V for HzOR in 0.5 M N2H4/1.0 M KOH. Furthermore, the constructed HzOR-assisted electrolyzer cell with Cu1Pd3/C ∥ Cu1Pd3/C as anode and cathode exhibits a cell voltage of 0.505 V at 10 mA cm−2 with exceptional endurance over 5 h. The current study advances competent CuPd alloys as multifunctional electrocatalysts for H2 fuel production by using a HzOR-assisted energy-efficient electrolyzer.