Highly enhanced bifunctionality by trace Co doping into Ru matrix towards hydrazine oxidation-assisted energy-saving hydrogen production

Abstract

As an alternative to oxygen evolution reaction (OER), the low-potential hydrazine oxidation reaction (HzOR) can assemble with hydrogen evolution reaction (HER) to fulfill the energy-saving H2 generation, which demands of developing high-quality bifunctional electrocatalysts for HER and HzOR. Herein, a simple one-pot wet-chemical method was employed to facilely prepared the highly dispersed RuCo alloy particles onto oxygenated carbon black (RuCo/C). With the trace doping of Co into Ru matrix, RuCo/C exhibits the significantly boosted bifunctional activity, superior to the recently reported counterparts, with low potentials of –13.3 and –76.8 mV at 10 mA·cm−2 for HER and HzOR, respectively. Additionally, the novel HER||HzOR electrolysis system just requires a small voltage of 215.4 mV at 100 mA·cm−2, and thus is easily operated under low-energy portable external powers (fuel cell and solar cell) with impressive H2 production, demonstrating the superiority in energy saving and convenient operation. Moreover, theoretical calculations unclose upon alloying with trace Co, the H2O dissociation energy barrier and hydrogen ad/desorption of HER can be simultaneously optimized on Ru active sites, and the rate-determining energy barrier of HzOR can be also greatly reduced. This study provides one simple but workable approach to prepare high-performance bifunctional HER and HzOR eletrocatalysts, highly promising for the energy-saving H2 production.