Preparetion Of High-performance Materials Using Vegetable Sponge As Templates

Natural plant fiber templates attract much attention due to the advantages of low cost, rich resource, renewable capability, environment friendly and so on. This thesis focused on the application of natural plant fibers in the synthesis of porous materials. In the first part, vegetable sponge was employed as exo-template to prepare biomorphic solid super bases CaO/C with high specific surface area, and the effect of humid air at room temperature on the structure of carbon was also studied. In the second part, the natural plant fibers were utilized to synthesize biomorphic visible-light photocatalyst.The main progresses of this thesis are:(1) The biomorphic solid base CaO/C has been prepared via an exo-templating pathway using vegetable sponge as template and calcium acetate as precursor. The resulting materials replicated the vegetable sponge morphology, with the reticular framework constructed by plenty of claviform fibers. These samples showed high specific surface area and strong basic sites, and exhibited good catalytic performance in the methylation of cyclopentadiene.(2) A new method was developed to prepare hierarchical pore structural carbon material. In this method, vegetable sponge and calcium acetate were used as carbon source and modifying reagent, respectively. Vegetable sponge was first converted to CaO/C by impregnation and thermal decomposition of calcium acetate, and then treated with saturated water vapor at room temperature for a month to generate mesopore, followed by washing with acid to remove Ca species. This strategy has the advantages of simple and moderate treating condition and the low-cost resource. It provides an optional method to prepare hierarchical porous carbon material.(3) Biomorphic visible-light photocatalysts have been prepared by introducing natural plants fiber, such as absorbent cotton and vegetable sponge, into the preparation of g-C3N4. Among these samples, g-C3N4SiO2 prepared using biomorphic SiO2 supporter, which was obtained using absorbent cotton fiber as exo-template, exhibited the best catalytic performance in photo-degradation of methyl orange (MO) dye. The apparent rate constant for degradation of MO on this sample is 4.5 times as much as on common g-C3N4.(4) A novel CN film has been prepared by sublimation of g-C3N4 followed by treating in the moist air at room temperature. This film showed the smooth surfaces, with the thickness less than 1μm. It has the graphite-like layered structure and a C/N ratio of 0.68, which are similar to powder g-C3N4. However, more O element was detected on this sample. The CN film shows stronger absorbance of visible light than powder g-C3N4, and is expected to play an important role in the visible-light photocatalysis.