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An ultrasonic-assisted resistance sintering furnace was developed by using an integrated crucible to transfer ultrasonic energy to silicate ceramic samples for improving the conventional sintering process. The silicate ceramic samples were prepared and sintered by conventional and ultrasound-assisted sintering processes. The shrinkage, water absorption, bulk density, crystalline phase, and morphology were investigated by using the Archimedes method, X-ray diffraction, and scanning electron microscopy. The results show that the densification and microstructure of the samples can be improved by the ultrasound-assisted sintering at lower sintering temperatures and sintering times. The optimum sintering temperatures in this study were 1160 °C and 1145 °C for the conventional and ultrasound-assisted sintering processes, respectively. The loading of ultrasonic waves in the sintering can homogenise the grain size and grain shape, and make the grain and pore distribution more uniform. The microstructure is remarkably improved at the appropriate sintering temperature and sintering times by ultrasonic-assisted sintering.

The development of efficient, recyclable, broad-spectrum photocatalysts was the primary objective in the field of photocatalytic wastewater degradation. Herein, a novel highly efficient ternary magnetic semiconductor composite was synthesized by integrating SrFe12O19, MoS2 nanoflower clusters, and SnS2 nanoflowers using high-temperature calcination and a one-step solvothermal method. The synthesized heterojunction nanocomposite was characterized using numerous analytical techniques, and its photocatalytic activity was evaluated under half sunlight intensity irradiation. The integration of SnS2 with SrFe12O19 and MoS2 effectively modified the crystal structure and morphology of SnS2 nanoflowers, leading to an increase in active sites while overcoming the significant electron–hole recombination rates of the individual components. The SrFe12O19/SnS2/MoS2 composite achieved 98.69% degradation of MB dye at a suitable pH of 6 and a period of 120 min of irradiation. Additionally, it maintained an excellent magnetic phenomena which contributed to it effortless to collect and reclaim from the residual mixture. After three cycles, the MB dye degradation remained at 84.07%, demonstrating its endurance and resilience. The scavenger test identified the superoxide radical as the primary agent responsible for dye destruction. This work provides study presents a synthesis method for highly efficient photocatalysts using in natural visible-light that can be recovered by simply applying an external magnetic field. [ABSTRACT FROM AUTHOR]

The synthesis and application of magnetic photocatalysts have become a critical topic in organic waste treatment. In this study, SrFe12O19 powder, SrFe12O19/SiO2 particles and SrFe12O19/SiO2/TiO2 photocatalysts were successfully produced using coprecipitation technique, Stöber process and solvothermal method, respectively. The degradation of methylene blue dye and simulated petroleum wastewater under simulated sunlight and ultraviolet light was used to assess the photocatalytic activity of the SrFe12O19/SiO2/TiO2 composites. Results showed the high photocatalytic performance of the produced SrFe12O19/SiO2/TiO2 photocatalysts with a 1 : 4 mass ratio of SrFe12O19 to TiO2 synthesized at 170 °C, whose surface has more hydroxyl groups as the active center. At 120 min of irradiation, the photodegradation rates of methylene blue and simulated petroleum wastewater were 83.94 % and 60.77 %, respectively. The photocatalytic activity of the Fe12O19/SiO2/TiO2 with ferrite semiconductor/insulator/semiconductor structure was improved by the action of the magnetic field of SrFe12O19. The SrFe12O19/SiO2/TiO2 composite particles can be recycled easily under an external magnetic field and show good application prospects in organic wastewater degradation. [ABSTRACT FROM AUTHOR]

Narrow-band gap metal oxide semiconductors, such as those based on Pb2+, Bi3+, and Sn2+ ions, have achieved significant success in the field of photocatalysis due to their effective utilization of visible light. The key is the presence of antibonding states derived from the lone-pair ns orbitals at the valence band maximum. In contrast, the feature of a narrow band gap in In-based metal oxides with the empty 5s orbital of the In3+ cation is actually rather uncommon. In this study, we present a mechanistic investigation of IrIn6XYO8 (X = Ga, In; Y = Ge, Sn, Ti), a class of narrow-band gap semiconductors, using first-principles calculations. Based on bond theory analysis, we determine the band edge electronic feature by elucidating the role of orbital interactions within In–O/In bonds. Leveraging the advantages of their narrow band gap and efficient carrier separation capability, IrIn6XYO8 (X = Ga, In; Y = Ge, Sn, Ti) demonstrate significant potential for photocatalytic water splitting. Moreover, by integrating band edge positions and Gibbs free energy calculations, we identify that IrIn6XTiO8 (X = Ga, In) are effective catalysts for overall water splitting under visible light irradiation, while IrIn6GaGeO8 presents as a highly promising photocatalyst for H2 evolution. [ABSTRACT FROM AUTHOR]

The addition of silicon carbide whiskers as reinforcing elements into the composite matrix plays the role of reinforcement and toughening, which can accelerate the renewal of traditional material products. Among the many reinforcing phases, the main advantage of silicon carbide whisker-reinforced composites is that they improve the strength, hardness, wear resistance, and high-temperature stability of the composites. Therefore, the application of silicon carbide whisker-reinforced composites under severe conditions such as high temperature, high pressure, high speed, and friction is of great importance. Its wide range of applications, involving aerospace, machinery manufacturing, the electronics industry, etc., has important scientific research significance and practical application value. In recent years, China has developed rapidly in the production of silicon carbide whiskers. This paper introduces the nature of silicon carbide whiskers, the strengthening mechanism, and the current research status of silicon carbide whiskers in the application of different matrix composites for performance enhancement, discusses the future challenges of related research work, and gives an outlook on the application prospects of silicon carbide whiskers. [ABSTRACT FROM AUTHOR]

The d 10 metal oxides with low effective mass and high mobility of photoexcited electrons have received much attention in photocatalytic water splitting. However, there are still challenges in practical application due to insufficient visible light absorption. Here, an unusual phenomenon of the In 2+ cation in PtIn 6 (GeO 4 ) 2 O and PtIn 6 (Ga/InO 4 ) 2 with a narrow band gap is systematically investigated using density functional theory calculations. According to chemical bond analysis, the final band edge structure results from the interaction between the empty In-5p orbitals and the occupied antibonding state of the In 5s-O 2p orbitals as well as the further hybridization of adjacent In cations in PtIn 6 octahedrons. The unique bonding characteristic of In 2+ cations endows them with a narrow band gap and visible light response ability. Moreover, the occupied antibonding state could weaken the strength of the In-O covalent bond and strengthen the orbital hybridization of the In-In bond, causing the conduction band minimum to be located in the electroactive In 6 cavity. This work reveals the origin of the narrow band gap of PtIn 6 (GeO 4 ) 2 O and PtIn 6 (Ga/InO 4 ) 2 in view of bond theory and shows that they are promising semiconductors for the application of photocatalytic H 2 generation.