Structural Studies of Multifunctional SrTiO₃ Nanocatalyst Synthesized by Microwave and Oxalate Methods: Its Catalytic...

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. Catalytic results reveal that microwave-synthesized catalyst showed 100% conversion and selectivity (>99% yield) for the chosen reactions than the conventional catalyst. Excellent catalytic activity of the STO microwave catalyst was due to high BET surface area, pore volume, and acidity of the catalyst, as compared to conventional catalyst. The present study marks the first-time application of perovskite-based SrTiO₃ as a potential multitasking cost-effective catalyst for the above reactions and synthesized using environment friendly microwave synthesis method.