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In this study, a series of cobalt-based spinel ferrites catalysts, including nickel, cobalt, zinc, and copper ferrites, were synthesized using the sol–gel auto-combustion method followed by a chemical reduction process. These catalysts were employed for accelerating hydrogen generation via the sodium borohydride hydrolysis process. A continuous stirred tank reactor was used to perform catalytic reactor tests. All samples were subjected to analysis using XRD, FESEM, EDX, FTIR, and nitrogen adsorption–desorption techniques. The results revealed that the cobalt-based copper ferrite sample, Co/Cu-Ferrite, exhibited superior particle distribution, and porosity characteristics, as it achieved a high hydrogen generation rate of 2937 mL/min.gcat. In addition, the higher electrical donating property of Cu-Ferrite which leads to the increase in the electron density of the cobalt active sites can account for its superior performance towards hydrolysis of NaBH4. Using the Arrhenius equation and the zero-order reaction calculation, activation energy for the sodium borohydride hydrolysis reaction on the Co/Cu-Ferrite catalyst was determined to be 18.12 kJ/mol. This low activation energy compared to other cobalt-based spinel ferrite catalysts confirms the catalyst's superior performance as well. Additionally, the outcomes from the recycling experiments revealed a gradual decline in the catalyst's performance after each cycle during 4 repetitive cycles. The aforementioned properties render the Co/Cu-Ferrite catalyst an efficient catalyst for hydrogen generation through NaBH4 hydrolysis. [ABSTRACT FROM AUTHOR]

Using a seed–growth method, chemical reduction in aqueous solution was used to create gold nanoparticles (AuNPs). As seeds, AuNPs have been created and used as a nucleating agent with regard to the gold colloids' anisotropic growth. The various seed quantities were added to the gold chloride-containing growth solution, and NPs have started to grow as a result. Au seeds are typically 20 nm in spherical and size in shape, while gold is 25–30 nm in size and spherical in shape. Peak absorption from nanospheres was measured between 535 nm and 530 nm. The surface plasmon band's absorption peaks moved to the short wavelength region. AuNPs are doped with PMMA to create thin films that can be used as saturation absorbers (passive Q-switching) for Q-switching in visible region and green LEDs at various frequencies in the RhB fluorescence region. Those properties include the suitability of the resulting NPs for optoelectronic applications. [ABSTRACT FROM AUTHOR]

A series of mesoporous nanoparticle P-CexZr1-xOy (PCZ) catalysts with abundant oxygen vacancies and high specific surface area were successfully prepared, exhibiting 100% formaldehyde conversion at room temperature (25 °C). The PCZ catalyst was investigated in depth utilizing TEM, BET, XRD, XPS, H2-TPR, and Raman characterization, it was found that the PCZ catalyst had an average particle size of 10 nm and a specific surface area of 108 m2/g; templating caused by P123 and effective doping of Zr atoms regulated the oxygen vacancies in the catalyst, altered the reduction characteristics and chemical state of cerium to formed the redox cyclic couple of Ce3+/Ce4+, which significantly enhanced the catalytic oxidation performance of the PCZ catalyst in the indoor environment. [ABSTRACT FROM AUTHOR]