Strontium Manganes Oxide Nanostructures as an Efficient Catalyst for Water Splitting Reaction

Hydrogen is known as an important carriers of energy that could be releases the energy by directly combustion, production of steam, operation of fuel cell and combustion by catalysis. Hydroelectric, wind energy, solar energy, geothermal energy and photovoltaic energy could be used for oxidation of water and producing the hydrogen [1]. Therefore, the oxidation of water is an efficient process that limited by the selection of methods and efficiency of used catalysts [2]. So finding the low cost and environmental friendly catalyst for splitting of water. Among the different elements, Mn is an attractive element for water splitting because of the suitable properties such as earth abundance, environmental friendly and low cost [3]. On the other hand, it is an efficient catalyst that used by nature for oxidizing water on plants, cyanobacteria and algae which called water oxidizing complex (WOC) [4]. Different compound of manganese are used in various fields such as catalysis, batteries, magnetite and electrochemistry [5]. Manganese is known as one of the important transition metals which is required for the survival and growth of numerous alive organisms. Attention to the chemistry of manganese compound depicts that the electron transfer reaction is the main reaction on biological systems [6]. One of the requisite for having a sustainable hydrogen economy is molding of technical methods to split water via the sun light and using of catalysts which used in photosystem (II) to create the aerobic atmosphere on the earth. Generation of hydrogen by water splitting is an import goal to store the solar energy. Finding and developing the efficient catalysts for splitting of water to H2 and O2 is one of the greatest challenge to create the big plan for oxidation of water [7]. The principal focus of this investigation is to prepare strontium manganese oxide by theultrasonic, methods. The influence of calcination temperature, and ultrasound irradiation power, and the presence of surfactant were investigated on morphology and size of strontium manganese oxid nanostructures. As-prepared nanoparticles were characterized by X-ray diffraction (XRD), 13th Annual Electrochemistry Seminar of Iran Materials and Energy Research Center (MERC), 22- 23 Nov, 2017 241 scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray energy dispersive spectroscopy (EDS) and ultraviolet–visible (UV–Vis) spectroscopy. Results have been indicated that by changing in method and reaction condition, product appeared in different size, morphology, and uniformity. The morphology and size of nanostructures have been influenced on the properties of nano-SrMnO3. For investigation the properties of the SrMnO3 was used in catalytic water splitting for O2evolution in presence of (NH4)2Ce(NO3)6. The effect of nano-catalysts and the concentration of (NH4)2Ce(NO3)6 have been studied on O2 evolution reaction. Results show that the efficiency of water splitting have been increased by enhancement in the size and uniformity of catalysts and the results were introduced the SrMnO3 nanostructures as a new and efficient catalyst for O2 evolution reaction. Figure 1 shows the TOF and TON diagram for water splitting reaction by SrMnO3 catalyst. Figure 1 The TOF and TON diagram