Sunlight driven photocatalytic performance of a Pt nanoparticle decorated sulfonated graphene–TiO2 nanocomposite

Abstract

An efficient Pt nanoparticle decorated sulfonated graphene–TiO₂ (SGTPt) ternary nanocomposite was prepared through a facile hydrothermal route followed by the polyol process. The physicochemical properties of the prepared photocatalyst were analyzed by various spectroscopic and microscopic techniques. The obtained SGTPt nanocomposite exhibited excellent visible light photocatalytic activity for the degradation of anionic and cationic dyes over a wide pH range. 1.5 wt% Pt NP loaded SGT photocatalyst exhibited a 4.4 and 2.0 fold higher photocatalytic activity toward methyl orange and rhodamine B degradation at pH 7 in comparison to pristine TiO₂. Furthermore, the cyclic test showed the photocatalyst to be highly stable and free radical trapping experiments disclosed that holes (h⁺) played a key role in photocatalytic degradation. It was inferred that the enhancement of the photocatalytic activity was due to the synergetic effect and the chemical bonding between sulfonated graphene, TiO₂ and Pt interfaces which led to an increased interfacial charge transfer rate.