Daylight photocatalytic activity of SnO2@Al2O3 core-shell: An experimental & first principles study

Two core-shell composite nanosystems of SnO2/Al2O3 have been synthesized using a simple sol-gel technique. Then, one composite is heated under oxygen-sufficient conditions and the other under vacuum conditions, respectively. The structural properties of the SnO2/Al2O3 composites are studied with an X-ray diffractometer (XRD), surface pore size analyser (BET), transmission electron microscope (TEM) and Fourier transform infrared spectrophotometer (FTIR). We have studied the optical properties of both composite systems using UV-visible spectrophotometers and photoluminescence (PL) spectrometers. Using DFT (VASP), we calculate the first principle calculations for both models representing the above experimental composite systems. From both experimental and theoretical analysis, we observe that the band gap of the systems changes depending on drying conditions. Further, electronic structure investigation through DFT and all the studies conducted through experiments more or less show the same trend. The photocatalysis application of the prepared core-shell composite systems for the degradation of methyl orange is also observed under sunlight.