Defective nickel zirconium oxide mesoporous bifunctional electrocatalyst for oxygen evolution reaction and overall water splitting

Designing a robust electrocatalyst for Oxygen evolution reaction (OER) and other energy transformation devices is still challenging. To meet this trial, numerous oxides and bimetallic oxides consisting of oxygen vacancies spring up a critical parameter for outstanding OER electrocatalyst. In this work, for the first time, single-phase zirconium nickel oxide (ZrNi4O) nanospheres with different concentrations of Ni are fabricated by a facile sol-gel method. Among all the synthesized series of ZrNi4O, Zr0.012Ni4.3O0.68 deposited on glassy carbon (GC) electrode exhibits remarkable OER performance requiring only 294 mV overpotential at 10 mA cm(-2). Such unusual performance is owing to the availability of a huge number of various oxygen vacancies created in the non-stoichiometric compound Zr0.012Ni4.3O0.68. In addition to this, the effect of substrate and medium on Zr0.012Ni4.3O0.68 is also investigated. The Zr0.012Ni4.3O0.68 is also analyzed as overall electrocatalyst for electrolysis in two electrode system requiring only 1.55 V cell voltage for 20mAcm(-2) current density. As the concentration of Ni varies in ZrxNi(4)-xO(sigma), the amount of oxygen vacancies increases in cubic system of ZrNi4O, consequently enhancing the conductivity of the electrode. That ultimately augments the intrinsic activity (specific activity) and empirical usage (Mass activity) of electrocatalysts toward OER.

Automated summary

In this study, single-phase zirconium nickel oxide nanospheres with different concentrations of Ni were successfully fabricated for the first time using a sol-gel method. Among these, Zr0.012Ni4.3O0.68 exhibited remarkable OER performance on a glassy carbon electrode, requiring only 294 mV overpotential at 10 mA cm(-2). This performance is attributed to the presence of a large number of oxygen vacancies in the non-stoichiometric compound Zr0.012Ni4.3O0.68.