Journal Article Titania modification with a ruthenium(II) complex and gold nanoparticles for photocatalytic degradation of organic compounds

Zheng, Shuaizhi  ,  Wei, Zhishun  ,  Yoshiiri, Kenta  ,  Braumueller, Markus  ,  Ohtani, Bunsho  ,  Rau, Sven  ,  Kowalska, Ewa

15 ( 1 )  , pp.69 - 79 , 2016-01-01 , Royal Society of Chemistry
Titania of fine anatase nanoparticles (ST01) was modified successively with two components, i.e., a ruthenium(II) complex with phosphonic anchoring groups [Ru(bpy)(2)(4,4'-(CH2PO3H2)(2)bpy)](2+) bpy = 2,2'-bipyridine ((RuCP)-C-II) and gold nanoparticles (Au). Various compositions of two titania modifiers were investigated, i.e., Au, Au + (RuCP)-C-II, Au + 0.5Ru(II)CP, (RuCP)-C-II, 0.5Ru(II)CP and 0.25Ru(II)CP, where Au and (RuCP)-C-II correspond to 0.81 mol% and 0.34 mol% (with respect to titania), respectively. In the case of hybrid photocatalysts, the sequence of modification (ruthenium(II) complex adsorption or gold deposition) was investigated to check its influence on the resultant properties and thus photocatalytic performance. Diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM) were applied to characterize the structural properties of the prepared photocatalysts, which confirmed the successful introduction of modifiers of the ruthenium(II) complex and/or gold NPs. Different distributions of gold particle sizes and chemical compositions were obtained for the hybrid photocatalysts prepared with an opposite sequence. It was found that photocatalytic activities depended on the range of used irradiation (UV/vis or vis) and the kind of modifier in different ways. Gold NPs improved the photocatalytic activities, while (RuCP)-C-II inhibited the reactions under UV/vis irradiation, i.e., methanol dehydrogenation and acetic acid degradation. Oppositely, (RuCP)-C-II greatly enhanced the photocatalytic activities for 2-propanol oxidation under visible light irradiation.

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