Structural Studies of Multifunctional SrTiO3 NanocatalystSynthesized by Microwave and Oxalate Methods: Its CatalyticApplication for Condensation, Hydrogenation, and AminationReactions

摘要

The present study deals with the synthesis ofSrTiO3 (STO) nanocatalysts by conventional oxalate andmicrowave-assisted hydrothermal methods. Thorough characterization of the nanocatalysts synthesized has been done byusing various techniques such as X-ray diffraction (XRD),Fourier transform infrared spectroscopy, N2 physisorption,transmission electron microscopy, total acidity by pyridineadsorption method, and acidic strength by n-butylaminepotentiometric titration, respectively. Structural parameterswere estimated by Rietveld refinement analysis from XRDdata which confirms cubic structure of SrTiO3. Traces of impurities such as TiO2 and SrCO3 were found in conventionalcatalysts, whereas these are absent in microwave catalyst. Brunauer?Emmett?Teller (BET) surface area of the microwavecatalyst was enhanced 14-folds compared to conventional catalyst. Increase in Lewis acid sites and their strength were alsoobserved in STO microwave catalyst. Catalytic performance of the catalysts was evaluated for various reactions, such asKnoevenagel condensation of benzaldehyde, catalytic transfer hydrogenation of nitrobenzene, and amination of benzaldehyde.Catalytic results reveal that microwave-synthesized catalyst showed 100% conversion and selectivity (>99% yield) for thechosen reactions than the conventional catalyst. Excellent catalytic activity of the STO microwave catalyst was due to high BETsurface area, pore volume, and acidity of the catalyst, as compared to conventional catalyst. The present study marks the firsttime application of perovskite-based SrTiO3 as a potential multitasking cost-effective catalyst for the above reactions andsynthesized using environment friendly microwave synthesis method.