Effects Of Au Particle Size On Glycerol Oxidation And Anti - Poisoning In Mesoporous Au / C Catalysts

The size of gold nanoparticles has a significant infiunce on the catalytic activity, while the size of the Au nanoparticles loaded on carbon is difficult to control. And the surpported Au nanoparticles are very easily poisoned for absorbing sulfur-containing materials. To solve these problems, the mesoporous Au / C was synthesized by one step through ligand co-surfactant self-assembly technique in this paper. The size of Au nanopaticles between 3-18 nm and without ligand adjuvant. This paper has researches on the performance of the selective oxidation of glycerol in aqueous media using the mesoporous Au / C catalyst, the effects of particle size on the reaction and the anti-poisoning properties of the Au catalyst.The first chapter is the literature review focusing on mesoporous materials, mesoporous carbon materials.The second chapter studies the effects of the Au nanoparticle’s sizes on the selectivity of oxidation of glycerol in aqueous medium. When the sizes of gold particles decrease, the conversion of glycerol increases and the selectivity of the glycerate is essentially unchange to the Au nanopaticles of 9-18 nm. In particular, when the size of Au nanoparticle is 9 nm, the catalyst has the best catalytic activity: the conversion is 51% and the selectivity is 80%. By hot filtration experiments and adding thiolated mesoporous silica(SH-SBA-15) solid, the activity center of the Au catalyst is the gold particles immobilized in mesoporous carbon bore, rather than the loss of the Au species. The catalysts have high stability and can be reused at least five times.The third chapter reports the anti-poisoning performance of the 9 nm nano-Au/C catalyst particles. Its poisoning performance is the following order: Mercaptan> potassium thiocyanate ≈ L- cysteine> thiourea. It is noteworthy that even though the octadecyl mercaptan was added at a high percentage(S / Au = 33 mol / mol) in the reaction system, the activity can be maintained 16%, indicating that Au / C catalyst has a high resistance to sulfur materials.The fourth chapter summarizes the full text.