Ultrasound-accelerated synthesis of uniform SrMnO3 nanoparticles as water-oxidizing catalysts for water splitting systems.

One of the major issue in the 21st century is the humans request to green energy. The best form of green, sustainable and safe energy is hydrogen source due to its ecological and economical aspects. Herein, In order to obtain a highly water-oxidizing catalysts for water splitting systems, the sonochemical procedure applied for fabrication of practical SrMnO3 nanoparticles. Also, the influence of various green capping agents (fruit juices and vegetable wastes) was studied on the formation of uniform particles. In the present work ultrasonic probe with 60 W/cm2 intensity and 18 kHz frequency was used for sample synthesis. Further, catalytic behavior of these nanomaterials investigated in water splitting reaction for O2 evolution by modifying the operational variables. The best catalytic behavior observed by those nanoparticles that indicated the smallest size and the most uniform morphology (Max amount of TON = 7.556). By utilizing the ultrasonic irradiation, the catalytic behavior of SrMnO3 nanoparticles improved (TON (ultrasonic bath) = 8.430, TON (ultrasonic probe) = 11.315). Therefore, nano-SrMnO3 was introduced as an efficient and novel nanocatalyst for O2 evolution reaction.

BaMnO3 nanostructures: Simple ultrasonic fabrication and novel catalytic agent toward oxygen evolution of water splitting reaction.

In the current paper, the main aim is to fabricate the BaMnO3 nanostructures via the sonochemical route. The various factor, including precursors, reaction time and power of sonication can affect the shape, size, and purity of the samples. We utilized X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray energy dispersive spectroscopy (EDS) to characterize the BaMnO3 nanostructures. The optical property of BaMnO3 nanostructures was explored by Ultraviolet-visible spectroscopy (UV-vis) and the energy gap was suitable for catalytic activity (about 2.75 eV). Changing the precursor can affect the size, nanoparticle shape, architectures, and uniformity of the samples. We employed the BaMnO3 nanostructures for O2 evolution reaction as catalysts. It can observe that increasing the homogeneity of the catalysts can increase the efficiency of the Oxygen evolution reaction. The maximum amount of the O2 evolution and the highest TOF and TON are related to nanoplate disc using barium salicylate as a precursor of barium. As a result, we can nominate the BaMnO3 nanostructures as an effective and novel catalyst for water-splitting reaction.

Sonochemical synthesis of SrMnO3 nanoparticles as an efficient and new catalyst for O2 evolution from water splitting reaction.

The principal focus of this investigation is to prepare the SrMnO3 nanostructures by different chemical methods such as ultrasonic, co-precipitation, microwave, and hydrothermal methods. The influence of calcination temperature, and ultrasound irradiation power, and the presence of surfactant investigated on morphology and size of SrMnO3 nanostructures. As-prepared nanoparticles were characterized by X-ray diffraction (XRD), 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. The results 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 of properties, the SrMnO3 was used in catalytic water splitting for O2 evolution 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 increased by enhancement in the size and uniformity of catalysts and introduced the SrMnO3 as a new and efficient catalyst for O2 evolution reaction.

Hydrothermal preparation of silver telluride nanostructures and photo-catalytic investigation in degradation of toxic dyes.

Different morphologies of Ag2Te nanostructures were synthesized using TeCl4 as a new precursor and hydrazine hydrate as reducing agent by a hydrothermal method. Various parameters that affect on morphology and purity of nanostructures were optimized. According to our experiments the best time and temperature for preparation of this nanostructure are 12 h and 120 °C. The photo-catalytic behaviour of nanostructures in presence of UV-visible light for degradation of methyl orange was investigated. Results show that the presence of UV light is necessary for an efficient degradation of dye in aqueous solution. On the other hand, as observations propose the Ag2Te reveal a strong photoluminescence peak at room temperature that could be attributed to high level transition in the semiconductor. Nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) techniques and UV-visible scanning spectrometer (UV-Vis).