Visible light-mediated photocatalytic degradation of caffeine via novel graphene-WS 2 aerogel Tajamul Shafi , Shamik Chowdhury, Brajesh Kumar Dubey, Shamik Chowdhury Indian Institute of Technology Kharagpur, India Visible light-mediated photocatalysis is a sustainable technology for tackling noxious organic pollutants in aqueous matrices. As such, there is a growing need for visible light active functional materials having excellent photocatalytic properties. Coupling transition metal dichalcogenides (TMDs) like molybdenum disulfide (MoS 2 ) or tungsten disulfide (WS 2 ) with graphene can result in many intriguing properties like excellent planar structure, superior optical properties, outstanding electron mobility, high specific surface area, as well as sufficient chemical stability, which are anticipated to be ideal for high performance visible light driven photocatalysis. In particular, the amalgamation of 2D materials with different physicochemical properties synergistically lowers the band gap, thereby improving the light harvesting properties. To this end, herein, a lightweight graphene aerogel decorated with 2D WS 2 nanostructures was synthesized via a one-pot hydrothermal method, and its photocatalytic performance towards the degradation of a model organic pollutant (i.e., caffeine) was systematically evaluated under visible light irradiation. The as-synthesized WS 2 @graphene aerogel (WGA) was characterized by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Further, the light absorption characteristics of the as-developed WGA material was investigated using UV–vis diffuse reflectance spectroscopy, and the band gap was computed to be 1.4 eV. Consequently, the as-prepared WGA showed a photodegradation efficiency of over 90% within 120 minutes, with optimal photocatalyst dose, initial solution pH, and initial caffeine concentration. Additionally, the as-synthesized WGA could be reused for at least three consecutive cycles without any significant deterioration in photocatalytic activity.
P102
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