| Abstract [eng] |
Electrochemical capacity and photoelectrochemical properties of mixed Zn-Co oxides coatings were investigated in this research. Mixed Zn-Co oxides were synthesized by precipitation and heat-treated at 400 ℃ and 500 ℃ temperatures. In order to determine the composition, structure, and morphology of mixed Zn-Co oxides X-ray diffraction, scanning electron microscopy, X-ray energy dispersion spectroscopy, nitrogen adsorption / desorption measurements and specific surface area calculations were used. It was found that mixed Zn-Co oxides, heat-treated at 400 ℃ temperature, were composed of wurtzite structure ZnO, spinel structure Co3O4 and very small quantities of spinel structure ZnCo2O4. Meanwhile, mixed Zn-Co oxides, heat-treated at 500 ℃ temperature were composed of very small quantities of wurtzite structure ZnO and higher quantities of spinel structure Co3O4 and ZnCo2O4. During synthesis mesoporous structures with cylindrical and slit-shaped pores were obtained. Heat-treating at 500 ℃ temperature led to the formation of particles with smaller pore volume, smaller average pore diameter and lower specific surface area. Mixed Zn-Co oxide coatings were formed from a mixture of oxides (molar ratio of Zn: Co = 1: 1) heat-treated at 400 ℃ and 500 ℃ temperatures. The spin coating method was used for the uniform and thin film deposition. The rotation speed was changed from 1000 to 1200 rpm and films were formed from 1 to 10 layers. Thin films photoelectrochemical and capacity properties were determined by the linear sweep voltammetry and galvanostatic charge / discharge measurement. It was established that more active coatings were formed from the mixed Zn-Co oxides heat-treated at 500 ° C temperature. The coatings formed from mixed Zn-Co oxide and heat-treated at 400 ° C temperature were characterized as a higher specific capacity, specific energy and specific power. It was determined that thin films of molar ratio Zn:Co = 1:1 are electrochemically active and can be used in photoelectrochemical cells and hybrid supercapacitors. |
