Titania (TiO2) is a wide band gap semiconductor that exhibits photocatalytic activity, high resistance to photocorrosion, and stability when exposed to light. The appropriate valence and conduction band energies of TiO2 are best suited to overcome the thermodynamic and the electrochemical potential required for photoelectrolysis of water. However, TiO2 as a photo anode material faces some significant challenges such as poor absorption of visible light, high carrier recombination, and limited charge-carrier transport. To overcome these limitations, we propose the synthesis of a composite material using carbon based graphene quantum dots (GQDs) and TiO2 nano particles. The GQDs are synthesized by an inexpensive wet chemical method using bird charcoal as a precursor. GQD nanostructures exhibit band gap tunability based on their size and has the potential to enhance the photo absorption in TiO2. In particular, the hybrid combination of the nano materials is expected to decrease the recombination of charge carriers, increase charge carrier mobility and aids to improve the overall photo-conversion efficiency. The size and surface morphology of the synthesized composite is studied using scanning electron microscope (SEM) image, atomic force microscope (AFM) and dynamic light scattering (DLS). Electrical/electronic performance of the composite is investigated by photocurrent density measurements. Further, optoelectronic properties are studied using photoluminescence (PL) spectrum and UV-visible transmission spectrum. The use of this combination of nano materials is non-toxic, inexpensive, and novel for photo electrochemical (PEC) water splitting application and has implications for cost effective solar fuel cell developments.

Graphene quantum dot-Titania composite materials for photocatalytic water splitting and photovoltaic applications

251st National Meeting (2016)

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