Ti-Doped SBA-15 Catalysts Used in Phenol Oxidation Reactions

Abstract

Two Ti-SBA-15 catalysts are synthesized using techniques that should either deposit Ti atoms specifically at the SBA-15 surface or allow Ti-containing species to exist at both the surface and within the bulk of SBA-15. The materials have been characterized by Fourier transform infrared (FTIR), Raman and UV visible spectroscopies, transmission electron microscopy, scanning electron microscopy/energy-dispersive X-ray spectrometry microscopies, and N 2 physisorption experiments. They have been applied in the total oxidation of phenol under catalytic wet air oxidation (CWAO) conditions and using photoand plasma promotion. The materials retain the structure of SBA-15 following the doping in both cases and Ti incorporation is confirmed. The nature of the incorporated Ti remains unclearwith evidence for anatase TiO 2 (from Raman and UV vis analysis) and evidence for atomically dispersed Ti from FTIR. In terms of reactivity, the presence of Ti in the in situprepared catalyst improves reactivity in the photopromoted reaction (increasing conversion from 28 to 60%), while both Ti catalysts improve reactivity in the CWAO reaction (by 7% over the in situ catalyst and by 25% over the grafted material). The presence of Ti has no beneficial effect on conversion in the plasma-promoted reaction. Here, however, Ti does affect the nature of the oxidized intermediates formed during the total phenol oxidation.

Reusable TiO2‐SBA‐15 Synthesized by Different Silica/Titania Ratios for Photodegradation

“…As can be seen in Table 2, the surface area of SBA-15 was found to be 732 m 2 /g, falling within the range of high-quality SBA-15 as 500-1300 m 2 /g . [30] Although the surface area and pore volume decreased slightly after TiO 2 loading, the BET area values of TiO 2 /SBA-15 (R) are still high with the range 621-583 m 2 /g. Additionally, the decrease in R values is ideal for promoting an increase in the wall thickness.…”

Morphological properties of ZnO nanostructures doped with Ag and Li for piezoelectric applications

“…On the other hand, the impregnation of metal or metal oxide nanoparticles onto the mesopore surface is a very useful strategy to achieve high efficiency in the catalytic reaction. The obtained catalysts and photocatalysts, by immobilization of various metal species, proved a high activity in the oxidation of organic compounds [21][22][23][24][25][26] as phenol. 21,24,26 Among the metals immobilized on mesoporous silica, nickel has been less studied in oxidation reactions 22 or photocatalytic degradation of organic compounds.…”

“…The obtained catalysts and photocatalysts, by immobilization of various metal species, proved a high activity in the oxidation of organic compounds [21][22][23][24][25][26] as phenol. 21,24,26 Among the metals immobilized on mesoporous silica, nickel has been less studied in oxidation reactions 22 or photocatalytic degradation of organic compounds. 23 In these reactions SBA-15 is among the most studied mesoporous silica as support with high surface area and ordered mesoporous structure to immobilization of various metals, and the obtained materials were used as catalysts 26 or photocatalysts.…”

“…21,24,26 Among the metals immobilized on mesoporous silica, nickel has been less studied in oxidation reactions 22 or photocatalytic degradation of organic compounds. 23 In these reactions SBA-15 is among the most studied mesoporous silica as support with high surface area and ordered mesoporous structure to immobilization of various metals, and the obtained materials were used as catalysts 26 or photocatalysts. [27][28][29][30][31] Most of the photocatalysts contain Ti, single or associated with another active metal, supported on SBA-15, and were used in organic compounds degradation from water.…”

Catalizadores Pd/SBA-15 en la oxidación catalítica vía húmeda del fenol

“…En la OCVH de fenol, existen un gran número de investigaciones donde se han probado catalizadores soportados y no soportados o en combinación con óxidos de Co, Mo, Mn, Ni, Fe, Cr, Zn, Cu, Ti, etc. [4][5][6][7][8][9][10][11][12][13][14] bajo diversas condiciones de reacción como las reportadas por Yang et al [15], Monteros et al [16] Baloyi et al [17] quienes obtuvieron una conversión de 100% de fenol y alrededor de 88% de carbono orgánico total (COT). Aunque hay un gran interés en el proceso de OCVH, no muchos estudios consideran condiciones operativas leves para el abatimiento del fenol.…”