Synthesis, characterization and photocatalytic behavior of TiO2–SiO2 mesoporous composites in hydrogen generation from water splitting

• Published in: Journal of materials science 2014-09, Vol.49 (18), p.6383-6391
• Main Authors: Niphadkar, P. S., Chitale, S. K., Sonar, S. K., Deshpande, S. S., Joshi, P. N., Awate, S. V.
• Format: Article
• Language: English
• Subjects: Catalysis; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Composite materials; Crystallography and Scattering Methods; Diffuse reflectance spectroscopy; Hydrogen evolution; Hydrogen production; Materials Science; Morphology; Photocatalysis; Photocatalysts; Polymer Sciences; Silicon dioxide; Sol-gel processes; Solid Mechanics; Titanium dioxide; Transmission electron microscopy; Water splitting; X ray powder diffraction
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-014-8365-2

TiO 2 –SiO 2 mesoporous composite photocatalysts with different proportions (in wt%) of TiO 2 and SiO 2 (TiO 2 –SiO 2  = 20:80, 40:60, 60:40, 80:20 and 100:0) were prepared by loading TiO 2 on as-synthesized Si–MCM-41 using sol–gel method. The physicochemical properties of composites were investigated by powder X-ray diffraction, N 2 adsorption–desorption measurements, transmission electron microscopy and UV–Vis diffuse reflectance spectroscopy. It is revealed that the titanium species are dispersed as TiO 2 having interaction with the surface of the support. Even at high TiO 2 loading, the mesostructural feature of MCM-41 was found to be intact without pore blockages. The change in morphology of TiO 2 particle was observed with increase in TiO 2 loading which may be due to different environment for the growth of TiO 2 . The photocatalytic evaluation of composites was carried out in production of hydrogen by water splitting. Among the prepared samples, mesoporous composite containing 60 % TiO 2 (MTi60) has shown the best results (0.08805 mmol of H 2 /h/g of TiO 2 ) compared to other composite photocatalysts. The catalytic performance of this sample was further enhanced (~8 times) after loading 1 % Pt in water splitting (0.70161 mmol of H 2 /h/g of TiO 2 ). 1 % Pt loaded on pure TiO 2 (MTi100) showed hydrogen evolution of the magnitude 0.26 mmol of H 2 /h/g of TiO 2 . TiO 2 –SiO 2 mesoporous composite photocatalyst showed much higher activity (~1.9 times) than amorphous silica-embedded titania catalyst having same composition.