Dual-Regulated Ru by alloying and Metal-Substrate interaction for Energy-Efficient hydrazine Oxidation-Paired hydrogen production

Overall water splitting (OWS) is the most potential method for large-scale hydrogen production, but the high-potential and sluggish oxygen evolution reaction (OER) greatly impedes its efficacy. Coupling the low-potential hydrazine oxidation reaction (HzOR) with the cathodic hydrogen evolution reaction (HER) has drawn widespread attention with energy-saving advantage and safe products, which necessitates the elaborate design of advanced bifunctional electrocatalysts. Herein, only using two complexes of Ru and Pd with 2,2′-bipyridine, the novel RuPd alloy/N-codoped carbon (RuPd/NC) composite was originally synthesize by direct mixing and pyrolysis, showing superior dual activity for HER and HzOR. Particularly, to deliver the current density of 10 mA cm −2 , RuPd/NC merely needs the potentials of −8 and −42 mV for alkaline HER and HzOR, far outperforming Pt/C and being most advanced among the previously studied counterparts. Moreover, the two-electrode overall hydrazine splitting (OHzS) needs ultrasmall voltages of 0.042 and 0.239 V to achieve 10 and 100 mA cm −2 , displaying great energy-saving feature. Moreover, the better activity for neutral HER, HzOR and OHzS on RuPd/NC was also found compared with Pt/C. The theoretical simulations uncover the water dissociation at Ru site with the greatly reduced energy barrier followed by the H desorption on the adjacent Pd site for HER, and the optimum activation energy on Ru site for HzOR, crediting to the synergistic regulation of alloying effect and metal-substrate interaction.