An environmentally benign route for the single-step synthesis of mesoporous sulfated titania is described by a seeding method using titanium oxysulfate as the titania source. The hydrolysis was performed in the presence of NaOH and seed under constant-volume conditions around 98 degrees C. The XPS and DRIFT spectra show the existence of a bridged bidentate sulfate complex on the surface of titania. The elimination of sulfur on heat treatment showed a characteristic change in mesoporosity, specific surface area, and crystallinity of the material. The transformation of sulfated titania to anatase was incomplete at 900 degrees C, showing a delay in crystallization due to the presence of sulfur. Studies on the thermal stability of the sulfated titania showed that the material obtained can be used for various applications at temperatures below 300 degrees C. The ammonia-TPD and catalytic performance studies of the sulfated titania samples showed the presence of strong acid sites.

The catalytic activity of Ni impregnated on various phases of titania, viz. rutile, anatase and high surface area, has been investigated for the hydrogenation of acetophenone. The TPR profile of Ni/rutile suggests a strong metal-support interaction. The observed catalytic activity order is Ni/rutile 4 Ni/anatase 4 Ni/TiO 2 . The greater activity of Ni/rutile is attributed to higher concentration of Ni on the surface and SMSI. The catalyst samples showed sintering of Ni when calcined at 900 1C, which resulted in a drop in their catalytic activity. The catalyst stability studies showed that activity is lost only marginally in rutile and anatase. The electronic interaction between Ni and rutile promotes the formation of electron enriched Ni-H species which interact with the carbonyl group of acetophenone. The hydrogenation proceeds with atom economy to form phenylethanol irrespective of the reaction conditions suggesting that these catalysts are of significant importance in green chemistry. The results obtained in this investigation clearly establish that Ni/ rutile, a non-porous support, is better for this class of reaction.

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The environmentally benign route of the organic free process was evolved in precipitating hydrated titania from titanium oxysulphate solution at 90 °C, using crystal nuclei with the addition of ammonia. The synthesized hydrated titania was found to be mesoporous and reactive, with a BET surface area of 277 m2/g. The hydrated titania on calcination in air at 500 °C for 2 h produced anatase mesoporous titania with a surface area of 100 m2/g. The as-synthesized and calcined mesoporous titania materials were characterized by X-ray diffraction, scanning electron microscopy−energy dispersive X-ray spectrometry, ultraviolet−visible/diffuse reflectance spectroscopy, inductively coupled plasma mass spectrometry, thermogravimetry differential thermal analysis, diffuse reflectance infrared Fourier transform spectrometry, and nitrogen adsorption−desorption measurements. The incorporation of phosphorus in the titania framework was found to inhibit crystallization and particle growth and was found to enhance thermal stability due to the formation of titanyl phosphate. The phosphate-modified hydrated titania exhibited mesopores with a high surface area (172 m2/g) after calcining at 500 °C. The esterification reaction performed on P-TiO2 samples showed the significance of an optimum quantity of anatase phase and phosphate content for catalytic activity.