MODIFICATION OF TIO2 AND ITS PHOTOCATALYTIC ACTIVITY ENHANCEMENT FOR DEGRADATION OF AQUEOUS STYRENE UNDER VISIBLE LIGHT

摘要: A VISIBLE-LIGHT-ACTIVE TIO2 PHOTOCATALYST WAS PREPARED THROUGH NITROGEN DOPING, EMPLOYING UREA AS NITROGEN SOURCE, BY SOL-GEL METHOD. THE PREPARED SAMPLES WERE CHARACTERIZED BY X-RAY DIFFRACTION, DIFFUSE REFLECTANCE SPECTRA AND FOURIER TRANSFORM INFRARED (FTIR) SPECTROSCOPY. ACCORDING TO THE XRD DATA, THE PARTICLE SIZE OF N-TIO2 IS SIGNIFICANTLY SMALLER THAN THAT OF COMMERCIAL TIO2-P25, WHICH IS AN IMPORTANT ADVANTAGE OF THE PHOTOCATALYSTS FORMED. UV–VIS SPECTROSCOPY SHOWS THAT NITROGEN WAS INCORPORATED INTO THE TIO2 LATTICE, AND SUCH INCORPORATION EXTENDS THE PHOTORESPONSE OF TIO2 FROM UV TO THE VISIBLE LIGHT REGION. THE PHOTOCATALYTIC ACTIVITY OF THE PREPARED PHOTOCATALYST UNDER VISIBLE LIGHT WAS ESTIMATED BY MEASURING THE DEGRADATION RATE OF STYRENE (25 MG L-1) IN AN AQUEOUS SOLUTION AND COMPARED TO COMMERCIAL TIO2-P25. RESULTS INDICATED THAT THE DEGRADATION RATIOS OF STYRENE ON THE PREPARED SAMPLES WERE HIGHER THAN THAT ON THE WELL-KNOWN PHOTOCATALYST TIO2-P25. IT IS A RESULT OF THE DOPING OF NITROGEN INTO THE TITANIUM LATTICE.