Synthesis, characterization and photocatalytic behavior of TiO sub(2)-SiO sub(2) 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: Catalysts; Dispersions; Materials science; Photocatalysis; Photocatalysts; Platinum; Titanium dioxide; Water splitting
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-014-8365-2

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