Study On Preparation And Photocatalytic Performance Of The C/TiO₂

In this article C/TiO₂ microplate and C/TiO₂ amorphous film were prepared by a new foaming-assisted method and traditional chemical vapor deposition method respectively. The C/TiO₂ microplate was used for liquid phase degradation, phenol servered as simulated organic pollutants in this testing, evaluating its photocatalytic performance. A wide spectrum of factors influencing photocatalytic activity has been explored, such as calcination temperature, roasting atmosphere, preparation method, pollutant concentration, pollutant species, and hole sacrificial agent. The C/TiO₂ amorphous film was used for gas phase degradation, formaldehyde servered as simulated gas phase contaminants in this testing, evaluating its photocatalytic performance. A sequence of factors influencing photocatalytic activity has been explored, such as calcination temperature, roasting atmosphere, and basis materials. XRD, TEM, SEM, BET, EDS, XPS, FTIR, UV-Vis DRS, UPS, and PL analysis means were adopted to characterize the two kinds of prepared C/TiO₂ catalysts, analyzing and speculating about the possible catalytic mechanism.For the C/TiO₂ microplate, wich was characterized by XRD and TEM. The Analysis showed that the microplate was anatase TiO₂ crystal phase, a large number of remaining carbon material in microplate can reduce the degree of crystallinity of the sample, and roasting temperature is the main influencing factor for C/TiO₂ microplate crystallization and phase transformation. TEM, SEM, and BET characterization analysis showed that the thickness of prepared C/Ti O₂ microplate is relatively homogeneous（less than 10 um）. At the micro-scale, the sample was accumulated by relatively uniform size 10-20 nm nanoscale grain in free arrangement, with the mesoporous structure and relatively narrow pore size distribution. EDS, XPS, and FTIR characterization analysis showed that the sample elements were C, O, Ti, and the doped carbon material was mainly about C-C, C-O, C=O or COOR. COO- and Ti formed bidentate chelating carboxyl structure existing in the sample, having unique electrophilic property, which can lead to the change of original state of electron density in TiO₂ crystal. XRD, FTIR, XPS, UV-Vis DRS, and PL characterization analysis showed that bidentate chelating carboxyl structure have electronic absorption effect. Without changing the sample crystal phase structure, it is not only influenced the original state of electron density in titanium oxide octahedral of TiO₂ crystal, but also changed the valence band structure of samples. And the bidentate chelating carboxyl structure can inhibit the recombination rate of hole-electron pair, improving the photon-generated carrier separation efficiency.For the C/TiO₂ amorphous film, wich was characterized by XRD and TEM. The Analysis showed that the prepared sample was amorphous phase. SEM and EDS characterization analysis showed that the sample elements were C, O and Ti, the surface elements distribution were relatively uniform and slight suborbicular clusters were dotted in the amorphous film. XPS characterization analysis showed that the sample elements were C, O, and Ti. However Al element was not doped in C/TiO₂ amorphous film. The doped carbon material was mainly about C-C, C-O, C=O or COOR, existing in C/TiO₂ amorphous film. UV-Vis DRS characterization analysis showed that the sample has two optical absorption thresholds at 350 and 420 nm respectively, corresponding to the band-gap energy of 3.54 eV and 2.95 eV. This is due to the doping carbon materials. As a result, the impurity introduced impurity level which formed photoproduction carrier capture trap, prolonging the life of photon-generated carrier. Combining with UPS characterization analysis, when C/TiO₂ amorphous film was inspired by the light, the built-in field helps drive photogenerated electrons to the Al substrate.Thereby increasing the photon-generated carrier separation efficiency in the process of light stimulate, achieving excellent photocatalytic performance.