Baby diaper's super absorbent polymer derived carbon templated NiCuP@NiCu nanostructures for green hydrogen production

Abstract

Water electrolysis is considered as the most favorable method to generate hydrogen because of its environmentally friendly approach. As an upgradation of this process, the introduction of urea gives improved energy conversion efficiency and can also be used for the treatment of urea-rich wastewater. Inspired by the above, a bifunctional electrocatalyst, namely NiCuP@NiCu supported on graphitic carbon, is prepared for the first time via high-temperature pyrolysis and in-situ phosphidization process. The carbon support endorses better electron transference, and the presence of mixed active metal redox couples (Mx+/My+, M = Ni&Cu) and their M-O/O–C bonds formation with urea molecule collectively leads to substantial UOR activity. Under alkaline conditions with 0.33 M urea in 1.0 M KOH, the NiCuP@NiCu/C drives 10 mA cm−2 current density with a minimum potential of 1.242 V and overpotential of 98 mV for urea oxidation reaction (UOR) and hydrogen evolution reaction (HER), respectively. What is significant is that NiCuP@NiCu/C is explored as a bifunctional electrocatalyst to construct two electrode electrolyzer, which only requires the minimum potential of 1.313 V to drive 10 mA cm−2 current density. Furthermore, the NiCuP@NiCu/C equipped electrolyzer is used under human urine sample and achieved the maximum H2 production of 0.387 mmol. From the aforementioned outcomes, this works delivers a facile method for exploring an efficient bifunctional electrocatalyst for urea electrolysis and providing a new path to real-time fuel approach enabled H2 production.