Advanced nanostructured photocatalysts based on reduced graphene oxide–TiO2 composites for degradation of diphenhydramine pharmaceutical and methyl orange dye
By L. M. Pastrana-Martínez, S. Morales-Torres, V. Likodimos, J. Figueiredo, J. Faria, Polycarpos Falaras, Adrián M. T. Silva. 2012
306 citations recorded by the source corpus.
Abstract Reduced graphene oxide–TiO 2 composites (GOT) were prepared by liquid phase deposition followed by post-thermal reduction at different temperatures. The composite materials were systematically evaluated as photocatalysts for the degradation of an important pharmaceutical water pollutant, diphenhydramine (DP), and an azo-dye, methyl orange (MO), under both near-UV/Vis and visible light irradiation as a function of the graphene oxide (GO) content. A marked compositional dependence of the photocatalytic activity was evidenced for DP and MO pollutants degradation and mineralization under both UV/Vis and visible light. Especially under visible light, optimum photocatalytic performance was obtained for the composites treated at 200 °C comprising 3.3–4.0 wt.% GO, exceeding that of the benchmark P25 (Evonik) catalyst. According to scanning electron microscopy, Raman spectroscopy, and porosimetry analysis data, this was attributed to the optimal assembly and interfacial coupling between the reduced GO sheets and TiO 2 nanoparticles. Almost total degradation and significant mineralization of DP and MO pollutants (in less than 60 min) was achieved under near-UV/Vis irradiation for the optimum GOT composites. However, higher GO content and calcination temperatures (350 °C) led to detrimental effects due to the GO excess and the disruption of the GO–TiO 2 binding. Photocatalytic experiments employing sacrificial hole and radical scavenging agents revealed that photogenerated holes are the primary active species in DP degradation for both bare TiO 2 and GOT under UV/Vis irradiation, while an enhanced contribution of radical mediated DP oxidation was evidenced under visible light. These results combined with the distinct quenching of the GO photoluminescence under visible and NIR laser excitation, indicate that reduced GO acts either as electron acceptor or electron donor (sensitizer) of TiO 2 under UV and visible light, respectively. Fine-tuning of the reduced GO–TiO 2 interface is concluded as a very promising route to alleviate electron–hole recombination and circumvent the inherently poor light harvesting ability of TiO 2 in the visible range.
Subfields: Biomedical Engineering, Materials Chemistry, Renewable Energy, Sustainability and the Environment
View Paper: https://www.semanticscholar.org/paper/0d27d3f5af799efae289d1dad8be4a90c615ab47
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Citations in the corpus
- Hydrothermal Synthesis of rGO-TiO2 Composites as High-Performance UV Photocatalysts for Ethylparaben Degradation (2020, methodology): “GO preparation was based on the modified Hummers method [37,53].”
- Post-combustion CO2 capture using mesoporous TiO2/graphene oxide nanocomposites (2015, result): “These findings are consistent with those from previous studies [27,28].”
- Recent Advances in Graphene Based TiO2 Nanocomposites (GTiO2Ns) for Photocatalytic Degradation of Synthetic Dyes (2017, background): “In this case, the dye acts both as a sensitizer for visible‐activation and as a pollutant during the photocatalytic process, promoting the electron transfer from the excited dye molecules state to the TiO2 CB while G acts as an electron scavenger, as in the UV mechanism [147].”