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

摘要

The present study deals with the synthesis of SrTiO3 (STO) nanocatalysts by conventional oxalate and microwave-assisted hydrothermal methods. Thorough characterization of the nanocatalysts synthesized has been done by using various techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy, N2 physisorption, transmission electron microscopy, total acidity by pyridine adsorption method, and acidic strength by n-butylamine potentiometric titration, respectively. Structural parameters were estimated by Rietveld refinement analysis from XRD data which confirms cubic structure of SrTiO3. Traces of impurities such as TiO2 and SrCO3 were found in conventional catalysts, whereas these are absent in microwave catalyst. Brunauer–Emmett–Teller (BET) surface area of the microwave catalyst was enhanced 14-folds compared to conventional catalyst. Increase in Lewis acid sites and their strength were also observed in STO microwave catalyst. Catalytic performance of the catalysts was evaluated for various reactions, such as Knoevenagel condensation of benzaldehyde, catalytic transfer hydrogenation of nitrobenzene, and amination of benzaldehyde. Catalyticresults reveal that microwave-synthesized catalyst showed 100% conversionand selectivity (>99% yield) for the chosen reactions than theconventionalcatalyst. Excellent catalytic activity of the STO microwave catalystwas due to high BET surface area, pore volume, and acidity of thecatalyst, as compared to conventional catalyst. The present studymarks the first-time application of perovskite-based SrTiO3 as a potential multitasking cost-effective catalyst for the abovereactions and synthesized using environment friendly microwave synthesismethod.