Facile green route sol–gel synthesis of nano-titania using bio-waste materials as templates

Abstract: Titania semiconductor is being used in a wide range of fields; however, the poor surface properties and meagre visible light absorption capacity of it stand as barriers for being used as an effective visible light active photocatalyst. To overcome these limitations, various strategies have been adopted, among which the usage of templates has been the topic of research for the past 10 years. Usage of the template during the synthesis of titania increases the surface area by reducing the agglomeration of nanoparticles and also shifts the absorption edge to the visible range. Nowadays, green synthesis has gained substantial attention as an effective, safe and environmentally friendly practice for the synthesis of nano-titania. Bio-waste pista shells, corn pith, and tamarind seeds which are regarded as unproductive have been used in the sol–gel synthesis of Pista Shell Templated Titania (PST), Corn Pith Templated Titania (CPT) and Tamarind Seed Templated Titania (TST). The synthesized templated titania was subjected to morphological, crystallite, surface characteristic and photocatalytic studies. XRD results of synthesized CPT, PST and TST exhibited that they possessed anatase form. The crystallite size of PST, CPT and TST was found to be 12.26 nm, 12.28 nm and 15.55 nm, respectively, proving the reduction in crystallite size than in non-templated titania. Efficient photocatalytic activity of templated titania was observed via the degradation of methyl orange, which proved the larger surface area of templated titania than that of non-templated titania. Pista shells, corn pith and tamarind seeds were found to grant a decisive support in the controlled growth of titania and in photocatalytic applications which stands out as a reason to be looked upon as an effective bio-waste green template in the synthesis of nano-titania. Graphic abstract: [Figure not available: see fulltext.]