Electrochemical Water Oxidation Catalyst: Iron/Nickel/Zinc mixed oxide

Switching from fossil fuels to renewable energies is an inevitable task that should beperformed in the near future to provide clean and sustainable energies for human beings. Watersplitting toward hydrogen production is a promising approach to store such energies. In this regard,there are some bottlenecks for water splitting systems. Among different solutions, electrocatalyticwater oxidation process is considered to be a breakthrough in water-splitting technology. Someresearch groups previously reported that Ni/Fe (oxy)hydroxides have the lowest overpotentialtoward water oxidation under the alkaline conditions. The purpose of this study is to describe anew procedure to synthesize an efficient Fe/Ni/Zn-based water-oxidizing catalyst by the thermaldecomposition of a trimetallic organometallic compound. The catalyst were studied using scanningelectron microscopy, transmission electron microscopy, electrochemical methods, X-raydiffraction, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy. In addition toNi and Fe as important ions for water oxidation, the present organometallic compound includesZn ion as an amphoteric ion which can be removed in the presence of KOH solution to obtain moreactive sites on the surface of the catalyst and thus a self-improvement is observed during reaction.On the basis of the obtained results, a structure similar to (Ni, Zn)Fe۲O۴ is proposed. Long-timeamperometry also indicated an increase in the current density. Continued CVs showed that thewater-oxidizing activity of the compound increased during the cyclic voltammetry process. SinceZn ions are amphoteric, they can be soluble in KOH solution and results in a self-improvement forthe catalyst. Removing the Zn ions from the NiFeZnOx structure may be a promising method toincrease the catalytic activity of the present oxide. Introducing a new procedure to synthesize anefficient Fe/Ni/Zn-based water-oxidizing catalyst by the thermal decomposition of a trimetallicorganometallic compound. The catalyst showed a good long-term stability and performance. Thecomposition of the compound was characterized by some common methods and found to be anefficient wateroxidizing catalyst.