TiO2/in-situ reduced GO/functionalized with an IL-Cr complex as a ternary photocatalyst composite for efficient carbon monoxide deterioration from air

•Successful synthesis of novel ternary composite; TiO2, RGO-IL and Cr.•High surface area RGO with attached IL-Cr(η6-C6H5) formed tricarbonyl complex.•[Cr(CO)3(η6-C6H5)] promotes CO elimination besides the photocatalyst activity.•Excellent elimination of CO (97%) from air.•Harmony between charge separations, surface area and coordination reaction.

Photocatalyst composited with titanium dioxide (TiO2) and reduced graphene oxide (RGO) functionalized with ionic liquid (IL) and chromium (Cr) was created. Characterization techniques, confirming the structure of RGO/IL-Cr(η6-C6H5), were established by X-ray diffraction, TEM, BET, XPS and FT-IR. The complex was covalently attached on the RGO sheets through an imidazolium-based IL linker. The layered structure of RGO, in combination with the active role of the IL in reaction, makes the synthesized catalyst more efficient for the excellent elimination of CO (97%). Interaction between Cr and CO leads to the corresponding Cr(ΙΙΙ) tricarbonyl complex, [Cr(CO)3(η6-C6H5)]. This complex could promote the yield of gas degradation by the reaction of [Cr(η6-C6H5)] with CO, besides the photocatalyst activity of TiO2. Compared with TiO2, TiO2/RGO/IL-Cr composite develops an almost 3-fold enhancement in the photodegradation rate towards CO under UV irradiation. The improved photocatalytic activity of this ternary system benefits from the synergetic effect between RGO and Cr, which is proven by the photocurrent-time experiments; this improvement facilitates the interfacial charge transfer and simultaneously the CO elimination. The results highlighted the importance of harmonization between charge separations, surface area augmentation and coordination reaction process, and this is important to achieve high photocatalytic efficiency.

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