Ru-doped 3D porous Ni3N sphere as efficient Bi- functional electrocatalysts toward urea assisted water-splitting

Developing efficient, stable and ideal urea oxide (UOR) electrocatalyst is key to produce green hydrogen in an economical way. Herein, Ru doped three dimensional (3D) porous Ni3N spheres, with tannic acid (TA) and urea as the carbon and nitrogen resources, is synthesized via hydrothermal and low-temperature treated process (Ru-Ni3N@NC). The porous nanostructure of Ni3N and the nickel foam provide abundant active sites andchannel during catalytic process. Moreover, Ru doping and rich defects favor to boost thereaction kinetics by optimizing the adsorption/desorption or dissociation of intermediatesand reactants. The above advantages enable RueNi(3)N@NC to have good bifunctional catalytic performance in alkaline media. Only 43 and 270 mV overpotentials are required forhydrogen evolution (HER) and oxygen evolution (OER) reactions to drive a current of10 mA cm(-2). Moreover, it also showed good electrocatalytic performance in neutral andalkaline seawater electrolytes for HER with 134 mV to drive 10 mA cm(-2 )and 83 mV to drive100 mA cm(-2), respectively. Remarkably, the as-designed RueNi3N@NC also ownsextraordinary catalytic activity and stability toward UOR. Moreover, using the synthesizedRueNi(3)N@NC nanomaterial as the anode and cathode of urea assisted water decomposition, a small potential of 1.41 V was required to reach 10 mA cm(-2). It can also be powered by sustainable energy sources such as wind, solar and thermal energies. In order to make better use of the earth's abundant resources, this work provides a new way to develop multifunctional green electrocatalysts. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved

Automated summary

In this study, Ru-doped 3D porous Ni3N spheres were synthesized as urea oxide electrocatalyst. The catalyst exhibited good bifunctional catalytic performance for hydrogen evolution and oxygen evolution reactions with low overpotentials. It also showed good electrocatalytic performance in neutral and alkaline seawater electrolytes. Furthermore, the catalyst demonstrated extraordinary catalytic activity and stability toward urea oxide. It can be powered by sustainable energy sources such as wind, solar, and thermal energies.