Materials Science Forum Vol. 1160

Abstract: In this work, photoelectron nanocomposites of TiO₂&CeO₂&Ag were synthesized by a co-deposition method using TTIP (Titanium TetraIsoPropoxide) and water solutions of Ce(NO₃)₃ and AgNO₃. Heat treatment of the precipitates at 600°C led to the formation of an anatase phase with the primary particles’ size of 14.1–15.2 nm. Molecules of Malachite green and Methylene blue are intensively adsorbed on the surface of nanocomposites. TiO₂&CeO₂&Ag nanocomposites show high photocatalytic activity to cationic dyes and weak – to anionic ones. The photocatalytic decomposition of cationic dyes is accompanied by a hypsochromic shift of chromophoric bands. Only the chromophoric part of the dye molecules is destroyed by temperature (catalytic process). Nanocomposites based on anatase containing 1–2 wt.% of Ag and Ce show the highest photocatalytic activity for the destruction of organic dyes.

Abstract: Kinetic studies of the photocatalytic decomposition of cationic dyes MB (Methylene Blue) and RhB (Rhodamine B), and hydrogen generation from a water–methanol mixture were carried out using nanosized particles of anatase and binary composites based on it with 2 wt.% of palladium or cerium. Nanocomposites were synthesized by a chemical method using TTIP (Titanium TetraIsoPropoxide) in the presence of aqueous salt solutions containing doping metals. The paper briefly describes the structure, morphology, and chemical composition of the anatase-based nanoparticles using modern physical-chemical methods. In the presence of TiO₂&Pd particles, the destruction degree of RhB and MB under the UV irradiation during 60 min reached 81.0–85.5%, and in the presence of TiO₂&CeO₂ particles – 95%. The dye destruction process was accompanied by a hypsochromic shift of chromophoric peaks, which indicated the decomposition products formation. The reactions are pseudo-first order, and the rate constants are within 10^-2. Photocatalytic activity for hydrogen generation using UV radiation showed increased activity (H₂ 3519 μmol·g^-1) for TiO₂&2wt.%Pd due to the possible penetration of palladium atoms into the anatase lattice with efficient separation of photogenerated charge carriers in this system.

Abstract: Production of nanoscale catalytic materials is an urgent technological challenge. Catalysts have a wide range of applications, such as for neutralizing nuclear waste, decontaminating water polluted with mercury, purifying the atmosphere from various micro-particles, in molecular sieves, and in chemical synthesis, oil refining, etc. Another important application of nanostructured materials is in rechargeable batteries and fuel cells, where their high specific surface area is essential to ensure the speed and effectiveness of the interactions between different materials. Active nanostructured materials with a sufficiently high density of controlled surface defects meet these requirements well and, therefore, offer significant potential for optimizing the high energy consumption in batteries. Currently, the particle size of natural and industrially synthesized manganese oxide materials is typically in the micron range or larger. From perspectives, the most developed and promising methods for synthesizing manganese dioxide are ion exchange, hydrothermal, electrolytic, and chemical synthesis. In this work, a distinctive method for synthesizing nanostructured manganese dioxide is proposed, described, and analyzed. Experiments were conducted to determine the optimal synthesis routes using the Self-propagating High-temperature Synthesis (SHS) method, as a distinctive technological approach that uses manganese ore enrichment waste as raw material and ammonium chloride as a pretreatment chemical agent.