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UDC 621.762Uniformly dispersed yttrium aluminum garnet (Y 3 Al 5 O 12 , YAG) ultrafine powders are synthesized by coprecipitating a mixed solution of aluminum and yttrium nitrates with ammonium hydrogen carbonate in the presence of sodium dodecyl sulfate (SDS) as a dispersing agent. The primary purpose of introducing SDS is to protect YAG particles from agglomeration. The evolution of phase composition and microstructure of the as-synthesized YAG powders are characterized by thermogravimetry/differential scanning calorimetry, X-ray diffraction, infrared spectra, and scanning electron microscopy. The results show that phase-pure YAG powders can be achieved by calcination of the precursor at 900°C for 2 h. Uniformly dispersed YAG powders with a particle size of approximately 90-100 nm are obtained with the optimum molar ratio of Al 3+ to SDS of 2, and excessive SDS restrains good dispersion of the YAG powders. The dispersion mechanism of SDS in the preparation process is discussed.

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BACKGROUND Biosynthesis of Ag nanoparticles (AgNPs) utilizing renewable materials and nontoxic chemicals has become highly desirable and is currently receiving tremendous attention. In this study, a facile and cellulose‐based approach was developed to biosynthesize AgNPs through tandem hydrolysis of silver sulfate and cellulose under hydrothermal conditions. RESULTS Well‐defined AgNPs of about 72.0 nm in size were biosynthesized with 0.30 g of cellulose at 200°C for 10 h. The particle sizes of the as‐synthesized AgNPs were positively affected by the reaction temperature and time, but on the contrary were negatively affected by the amount of cellulose employed. The results from Fourier transform infrared spectroscopy showed that the cellulose‐hydrolyzed products (saccharides or aldehydes) were accountable for the bioreduction of the Ag ions, and the C = O (C–O) groups in the aldehydes or saccharides played critical roles in capping the AgNPs. Additionally, in the presence of the as‐synthesized AgNPs, enhanced surface fluorescence of methyl orange was achieved. CONCLUSION A biological and maneuverable strategy was successfully developed for the synthesis of AgNPs by a hydrothermal route through tandem hydrolysis of silver sulfate and cellulose. Thus, this environmentally friendly method is anticipated to be utilized for the biosynthesis of AgNPs and opens up avenues to prepare other metal nanoparticles from metal sulfates. © 2013 Society of Chemical Industry

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