The Assembly And Application Research Of Titanoniobate Nanosheets Composites

In this paper, HTiNbO5nanosheets was successfully synthesised via exfoliating layered HTiNbOs prepared by H+ion-exchange of layered KTiNbO5, which was fabricated by solid-state reaction (SSR) method and polymerizable complex (PC) method, respectively. HTiNbO5nanosheets as-prepared exist higher surface acidity and BET surface area. The catalytic activity of the as-prepared samples was investigated through selective nitration of toluene. Both of these two nanosheets sols were used to obtain exfoliation-restacking e-HTiNbO5/MOx (M=Ce, Fe) nano-composites by compositing with transition metal oxide sol, the photocatalytic activities were evaluated by ethyl mercaptan oxidation under natural and UV irradiation.The structure, morphology and property were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), laser Raman spectroscopy (LRS) spectra, thermal analysis (TG-DTA), UV-Visible diffuse reflectance spectroscopy (UV-vis DRS), temperature programmed desorption (NH3-TPD), and other physical and chemical testing means. The regioselective nitration of toluene was used as a probe to evaluate the acid catalytic activity of the e-HTiNbO5samples, and the experimental result was detected by gas chromatographic (GC) analysis. The adsorption species on the catalysts were analyzed by fourier transform infrared spectroscopy (FT-IR).KTiNbO5, HTiNbO5and e-HTiNbO5have the similar band gap energy. The band gap energy of the samples prepared by modifying the precursor (SSR method) were relatively higher than the samples prepared by modifying the precursor (PC method), and the change rules (spectral response) of e-HTiNbO5-SSR and e-HTiNbO5-PC are different. The amount acid of HTiNbO5-PC is three times as HTiNbO5-SSR, and the e-HTiNbO5also display the same situation, and the result of the catalytic activity for nitration of toluene show that, e-HTiNbO5exhibit a higher ratio of p-MNT to o-MNT than HTiNbO5, due to the higher amount acid and BET surface area.The BET surface area of e-HTiNbO5-SSR, e-HTiNb05/Ce02-SSR and e-HTiNbO5/Fe2O3-SSR are84.0m2·g-1,55.9m2·g-1and196.9m2·g-1, respectively. The BET surface area of e-HTiNbO5/Fe2O3-SSR was significantly increased. The as-prepared catalyst e-HTiNbOs/CeO2-SSR exhibits the highest photocatalytic oxidation activity among the three catalysts (e-HTiNbO5-SSR, e-HTiNbO5/CeO2-SSR and e-HTiNbO5/Fe2O3-SSR), these three catalysts show significant adsorption and photocatalytic activities under the visible light irradiation after static adsorption. The photocatalytic activities of the catalysts (e-HTiNbO5-PC, e-HTiNbO5/CeO2-PC and e-HTiNbO5/Fe2O3-PC) prepared by KTiNbO5-PC as precursor were similar to e-HTiNbO5-SSR, e-HTiNbO5/CeO2-SSR and e-HTiNbO5/Fe2O3-SSR under the visible light irradiation after static adsorption.