Synthesis Of Gold - Carbon Catalysts With Core - Shell Structure And Its Application In Reduction Of Nitro Compounds

It is one of important method to improve the catalyst stability thar the gold nanoparticles loaded on ordered mesoporous carbon supporter. Compared with the general block mesoporous gold/carbon catalyst, the gold nanoparticles loaded on the ordered mesoporous core-shell structure carbon material, not only can improve the stability of the catalyst, but also can obtain higher catalytic activity because of short channel advantages of mass diffusion process of the core-shell structure carbon carrier. Therefore, this paper mainly introduce the synthesis of different core-shell structure gold/carbon catalyst through the hydrothermal method, and its application in the reduction reaction of derivatives nitrobenzene.The full text is divided into five chapters. The first chapter is literature review, mainly including nano-gold catalysts, and mesoscopic research progress of order mesoporous carbon materials.In chapter 2, it introduces the morphology controlled and ordered mesoporous gold/carbon nanomaterials. And it based on organic-organic self-assembly method, we use the commercial three block copolymer F127 as a soft template, low-molecular-weight phenolic resin as carbon source, Au nanoparticles dispersed by the thiol as gold source to synthesis the Au/C ordered mesoporous materials. According to the "layer by layer " growth mechanism, control the hydrothermal synthesis conditions to obtain the ordered mesoporous Au/C nanomaterials. The characterization methods such as XRD, SEM, TEM showed that the Au/C materials can be divided into monodisperse dodecahedron carbon crystal, carbon nanorods(length to diameter ratio is about 3), carbon nanospheres( the diameter is about 120 nm), and each has ordered mesoscopic structure(body centered cubic structure), high surface area(565-652 m2 / g), large pore volume(0.32-0.32 cm3 / g) and uniform pore size distrubutons(2 nm). Size of 15 nm gold nanoparticles are limited in carbon material. The obtained catalysts do not be seen obvious reunion, even calcination temperature rising to 700 oC, shows its high thermal stability.In chapter 3, small size order mesoporous Au/carbon catalyst has the selectivity and efficiency to the reduction of nitro to amino. In this chapter, we researched the short channel diffusion and mass transfer mechanism of the catalyst, comparing the nanometer catalyst and bulk p6 mm Au/C nanometer catalyst. The repeat experiment shows that the catalyst is stable, for not seeing obvious loss of Au. In the research process, the catalyst with the SBA-15 decorated with thiol also have high activity in the reduction reaction, which represents that the activity is a multiphase nanometer Au catalysts.In chapter 4, we use a facile one-step hydrothermal route to synthesis yolk-shell structured Au@C nanospheres catalysis. Commercial available triblock copolymer pluronic act as a template and phenolic resol as a carbon source. The size of as-synthesis Au nanoparticals is 15 nm, which is dispersed in the hollow mesoporous carbon shell, and the thickness of the shell is 6 nm. And the size of Au is not larger after calcination. The yolk-shell structured Au@C nanoreactors(Au@HCN) with ultrathin shells exhibit highly catalytic activity in confined catalysis.