Visible active metal decorated titania catalysts for the photocatalytic degradation of Amidoblack-10B

In order to get high degradation efficiency in the visible region, different concentrations of active transition metals such as nickel and ruthenium were impregnated over titania synthesised by sol–gel method. The physico chemical properties of the catalysts were studied by various instrumental techniques such as X-ray diffraction, UV–visible diffuse reflectance spectroscopy, BET surface area analysis, Transmission Electron Microscopy, FT-IR spectroscopy, Raman Spectroscopy and X-ray photoelectron spectroscopy. The photocatalytic decolourisation/degradation of a widely used dye namely Amidoblack-10B was studied over metal loaded titania under both UV and visible light irradiations and monitored by using UV–visible spectrophotometer/TOC analyser. Photocatalytic activities of bare and metal titania catalysts were compared. The optimised reaction parameters for the complete decolourisation of AB-10B over bare titania under UV irradiation were found to be: 0.15 g of TiO2, 3 × 10−4 M [AB-10B] at its natural pH. Among the catalysts, Ni/TiO2 (1%) and Ru/TiO2 (1%) decolourised completely 100% at 330 min and 210 min with rate constant values of 9.39 × 10−3 min−1 and 2.3 × 10−2 min−1 respectively. Both nickel and ruthenium were found to be recyclable upto 3 cycles without any loss in their photocatalytic activities. The extent of degradation of Amidoblack-10B and its mineralisation were confirmed further by HPLC.

► Visible active photocatalysts with Eg < 3.2 eV were synthesised by simple technique. ► 100% decolourisation of dye was observed in shorter time for Ru/TiO2 (1%). ► Optical response in visible region was found to be higher for M/TiO2 than bare TiO2.