Preparation Of Effective Gas Diffusion Photoelectrode And Study On Their Catalytic Degradation Performance Of Benzaldehyle

Based on air quality is deteriorating, photocatalytic technology has been widely development in terms of air purification. Among them, Ti O₂ with strong oxidability, low price, stable performance and ease modification, has great research potential in terms of air pollution. Therefore, the preparation, modification and mechanism of Ti O₂ photoelectrode has been discussed in this paper and the details are lists as follows:Based on employing the surfactant cetyltrimethyl ammonium bromide, titanium tetrachloride and conductive carbon felt as template, titanium source and carrier, respectively, mesoporous titanium dioxide/conductive carbon felt（UH-MPT/CCF） composites photoelectrode material were prepared by ultrasound-assisted hydrothermal synthesis method. The structure of obtained samples was characterized by X-ray diffraction（XRD）, raman spectrometer, X-ray photoelectron spectroscopy（XPS）, scanning electron microscopy（SEM）, transmission electronic microscopy（TEM）, fourier transform infrared spectroscopy（FT-IR）, nitrogen adsorption-desorption. The results show that the mesoporous processing can increase the specific surface area and active center（·OH and Ti3+） of the UH-MPT/CCF, the Ti O₂ loading can enhance the absorption and the electron transfer, and the bias voltage can accelerate the separation of photogenerated electronic-hole pairs. Under the multilateral collaborative modified, degradation rate of benzaldehyde is 83.9 % by UH-MPT/CCF for 100 min, 1.38, 1.75 and 2.38 times as high as that of hydrothermal method was applied to synthesis mesoporous titanium dioxide/conductive carbon felt（H-MPT/CCF）, no porous titania/conductive carbon felt（NPT/CCF） and P25/CCF, respectively.Beside, the photoelectrode material of Pt doped mesoporous Ti O₂/conductive carbon felt（Ti O₂-Pt/CCF）, Mn doped mesoporous Ti O₂/conductive carbon felt（Ti O₂-Mn/CCF）, Fe doped mesoporous Ti O₂/conductive carbon felt（Ti O₂-Fe/CCF） and Zn doped mesoporous Ti O₂/conductive carbon felt（Ti O₂-Zn/CCF） was obtained by the same preparing conditions. The results show that the Pt ion doping can bring impurity level, reduce the band gap of Ti O₂, at the same time, Pt acts as a photo-electron and hole trap, and inhibits the electron and hole recombine. Thus, the MPT-Pt/CCF have higher photoelectric catalysis efficiency.In the end, choosing benzaldehyde as the target degradation product, the photoelectrocatalytic performance and degradation mechanism of MPT/CCF has been dicussed. According to the results of GC/MS analysis, the mechanism of degradation process of gasous benzaldehyde was proposed. At same time, the optimum preparing conditions of MPT/CCF photoelectrode is secondary load and 500℃ calcine. The optimum catalytic condition is 55 % of humidity, 10 V of bias voltage, 35 ℃ of temperature, 40 mg/m3 of initial concentration and 20 cm of electrode distance.