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The Bi2O3/Bi2SiO5 heterostructures were obtained with various samples of silica as a precursor: on the basis of biogenic silica isolated from rice husk and rice straw and the silica of mineral origin. A mixture of Bi(NO3)3 and SiO2 with a mass content of 15% was used for synthesizing all the samples. Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), X-ray phase, X-ray fluorescence, and ultraviolet-visible diffused reflectance spectroscopy (UV-vis DRS) were used to systematically characterize as-obtained materials. Photodegradation of methyl orange in neutral aqueous solutions (pH = 6.8) under UV irradiation was studied to evaluate their photocatalytic activities. Morphology, bandgaps, the value of the zero charge point, and photocatalytic activity of the samples depended on the characteristics of the original silica. The degree of methyl orange degradation reached the maximum values (81%-85%) for samples based on precipitated silica from rice husks, straw, and the minimum value (16%) for a composite with thermal silica from rice straw. Composites based on thermal silica from rice husks and reagents from mineral raw materials did not statistically differ from each other in the degree of methyl orange degradation (67%-74%). [ABSTRACT FROM AUTHOR]

Materials based on nickel- and zinc-doped TiO2(B), consisting of mesoporous nanorods, are produced via hydrothermal synthesis. Complementary methods are used to study the mechanism of doping and the physicochemical properties of the synthesized samples. According to the results of testing of materials in the cells of lithium- and sodium-ion batteries, it is found that the doping of TiO2(B) with nickel and zinc has a favorable effect. [ABSTRACT FROM AUTHOR]

In this study, TiO2(B) metastable β-TiO2 or bronze TiO2 was doped with Zr4+ (Zr/Ti = 0.03; 0.06) through hydrothermal approach. The materials were shown to be nanobelts (thickness: 10–l5 nm, width: 50–100 nm, length: several micrometers, and specific surface area: 72–76 m2/g). Doping the TiO2(B) structure with Zr4+ was found to be accompanied by the formation of Ti1−xZrxO2(B) (x = 0.03; 0.06) solid solutions, where the unit cell volume increases as the zirconium content rises. For doped TiO2(B), electrical conductivity increased by two order of magnitude, from 1.6 × 10−11 in an undoped sample to 8.2 × 10−10 S/cm for Zr/Ti = 0.06. After 90 charge/discharge cycles at the C/10-rate, Ti0.94Zr0.06O2(B) electrode had a capacity of 165 (mA h)/g. For undoped TiO2(B), this parameter was only 135 (mA h)/g. Moreover, Ti0.94Zr0.06O2(B) retained a reversible capacity of about 107 (mA h)/g even under an increased current load (5C). The major factors influencing the electrochemical behavior of Ti0.94Zr0.06O2(B) are the enhanced stability of the structure to lithiation/delithiation and an improved electrical conductivity. [ABSTRACT FROM AUTHOR]

Recent results of plasma electrolytic oxidation modification of the surfaces of Ti as well as NiTi alloy obtained by a joint effort of Institute of Chemistry FEB RAS, Institute of Strength Physics and Materials Science SB RAS, and Russian Ilizarov Scientific Center for Restorative Traumatology and Orthopedics are demonstrated in comparison with the literature ones. Conditions of coating synthesis determine their functional designation. It is presented that purposeful selection of the electrolyte composition used for coating formation has allowed to obtain layers containing Ca and P, whose bioactivity is confirmed both in vitro and in vivo. Prospects for the application of the plasma electrolytic oxidation method for the formation of the composite bioinert coatings at the titanium nickelide surface improving its morphological structure and electrochemical properties and significantly reducing the quantity of nickel ions releasing into the organism are demonstrated. [ABSTRACT FROM AUTHOR]

Sulfide ZnS-SiO 2 composite photocatalysts with biogenic silica matrix were prepared by sol-gel method based on wet gel and xerogel. FT-IR, SEM, XRD, EDXRF, UV-Vis, and XPS methods were systematically used to characterize the obtained materials. The use of support allowed to obtain stable porous (S BET  = 79-105 m 2  g -1 ; V pore  = 0.25-0.17 cm 3 ·g -1 ) ZnS-SiO 2 photocatalysts in aqueous solutions. Zn 2+ content in methyl orange solution after its degradation was 0.4 MPC. ZnS-SiO 2 composites had 3.68-3.70 eV band gap. The obtained materials were photoactive under different irradiation conditions (sunlight, UV-light, Xenon light, visible light) due to effective separation of charge carriers (e - and h + ). Methyl orange degradation degree under UV light excitation was 35-88%, under sunlight - 11-30%. ZnS-SiO 2 composite synthesized using silica xerogel showed a greater photoactivity due to a presence of cone-shaped or cylindrical pores with one open end in its structure and a higher content of ZnS photoactive component. A comparative study of photocatalytic performance of methyl orange degradation by ZnS-SiO 2 under UV irradiation was investigated using radical scavengers. • O 2 - was main active species during MO degradation under UV irradiation, and electrons played additional role during the photocatalytic process., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)