Abstract
In this study, a series of TiO2/rGO photocatalysts were obtained with a two-step procedure: a solvothermal method and calcination at 300–900 °C in an argon atmosphere. It was noted that the presence of rGO in photocatalysts had an important role in the changes in crystallite size and specific surface area. In TiO2/rGO samples, different surface functional groups, such as C−Cgraph, C−Caliph, C−OH, C=O, and CO(O), were found. It was observed that rGO modification suppressed the anatase-to-rutile phase transformation. The photocatalytic activity of the obtained nanomaterials was investigated through the decomposition of methylene blue under UV and artificial solar light irradiation. It was found that the adsorption degree played an important role in methylene blue decomposition. The experimental results revealed that TiO2/rGO samples exhibited superior removal efficiency after calcination for methylene blue compared toTiO2 without rGO, as well as a commercial photocatalyst KRONOClean 7000. It was noted that photocatalytic activity increased with the increase in the calcination temperature. The highest activity was observed for the sample calcined at 700 °C, which consisted of 76% anatase and 24% rutile. This study clearly demonstrated that TiO2/rGO samples calcined in argon can be used as efficient photocatalysts for the application of methylene blue decomposition.
Highlights
Titanium dioxide is commonly used in the photocatalytic process of water purification for the decomposition of different types of organic pollutants, such as heavy metals, pesticides, dyes, and phenols [1,2]
It was found that both rGO modification and the calcination process strongly impacted the crystallite size, the changes in the crystal structure, and the specific surface area of the tested samples
The red-shift in the adsorption edge and the narrowing of the band-gap energy has been found to correspond to changes in the TiO2 phase composition, especially when rutile was present in the tested samples [41,42]
Summary
Titanium dioxide is commonly used in the photocatalytic process of water purification for the decomposition of different types of organic pollutants, such as heavy metals, pesticides, dyes, and phenols [1,2]. Carbon nanomaterials are an interesting group of carbon precursors that can be used in TiO2 modification due to their unique porous structure, electronic properties, and large adsorptive capacity [8]. Conventional carbon materials, such as carbon black, activated carbon, and graphite, as well as graphitized materials have been widely used in heterogeneous catalysis for many years [9]. Thanks to its unique electronic properties, modification with graphene brings many benefits, such as suppressing electron–hole pair recombination and increasing the specific surface area of tested photocatalysts
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