Abstract
The photocatalytic degradation of gaseous toluene was investigated on TiO2 nanoparticles coated on reduced graphene oxide. Reduced graphene oxide-TiO2 composite (RGO-TiO2) was synthesized via two step processes. The prepared RGO-TiO2 composite was characterized using SEM, XRD, and UV-visible spectra. A significant increase in light absorption to visible light was observed by RGO-TiO2 compared with that of pure TiO2 nano particles. The photocatalytic degradation efficiency of the RGO-TiO2 composite was much higher than that of the P25 TiO2, 95% and 40% respectively. In our investigated conditions, the initial concentration, flow rate and relative humidity had significant influences on the photocatalytic degradation of gaseous toluene. The most efficiency was recorded at the 0.3 ppm concentration, 1L/min flow rate and 30% relative humidity. We believe that this TiO2 based composite material can be effectively used as a highly active and stable photocatalyst to remove various indoor air pollutants especially gaseous toluene. The photocatalytic degradation efficiencies of toluene increased slowly below 20% relative humidity and then decreased as the relative humidity increased further. The main reason of enhanced photocatalytic property might be the strong electron transfer ability, and the increased adsorption capacity of RGO sheets in the composites as well as the retarded charge recombination rate contributed by the energy level of the two materials. We believe that this TiO2 based composite material can be effectively used as a highly active and stable photocatalyst to remove various gaseous pollutants.
Highlights
Heterogeneous photocatalytic oxidation has been studied for several decades and shown to be an effective method for dealing with the environmental pollution problems, such as air cleanup, water disinfection, hazardous waste remediation, and water purification [1]-[7]
The energy-dispersive X-ray (EDX) spectra of the RGO-TiO2 composite contained peaks corresponding to the Ti, Pt, O, and C atoms, the peaks of Ti and O atoms were likely associated with TiO2, while the C atom peak may have been related to RGO
We studied the photocatalytic activities of RGO-TiO2 composite for the photocatalytic degradation gaseous toluene under different conditions
Summary
Heterogeneous photocatalytic oxidation has been studied for several decades and shown to be an effective method for dealing with the environmental pollution problems, such as air cleanup, water disinfection, hazardous waste remediation, and water purification [1]-[7]. The two-dimensional structure, large surface area, outstanding electronic and catalytic properties of graphene make it become a suitable candidate for incorporating with TiO2. For both graphene and reduced graphene oxide composites, the electrons in TiO2 generated by photons can be moved across the carbon sheets, which reduce the recombination of photon-generated electron-holes [18]. These kinds of materials have a high adsorption capacity, which enhances the photocatalytic performance of TiO2 nanoparticles [19]
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