Tóm tắt luận án Nghiên cứu tổng hợp vật liệu SnO2 có cấu trúc Nano đa cấp và ứng dụng trong cảm biến khí, xúc tác

<p> 1. Synthesis of SnO2 with hierarchical nanostructures using template CTAB by hydrothermal method with ultrasound. Morphology of SnO2materials was much dependent on the solvent and ultrasonically assisted hydrothermal process. Synthesized conditions: ultrasonic radiation, hydrothermal temperature of 180 ᤪ C, 0,5 g SnCl4in 35 ml of methanol solvent provided 0-3 porous spheres SnO2 with a high surface area 227 m 2 /g. The 0-3 porous spherical materials with a size 500-600 nm in diameters consisting of nanopartices less than 16 nm. The mechanism for the formation of 0-3 porous spheres proposed as shown scheme 3.1. We discovered methanol solvent is favorite for forming the 0-3 porous spherical structure for the first time. 2. Having successfully synthesized of SnO2 with 1-3 urchin in hydrothermal conditions: 1.5 mmol Na 2SnO3.3H2O, 20 ml NaOH 0.35 M and 20 ml ethanol. The possible mechanism SnO2 with 1-3 urchin isrecommended as scheme 3.2. The research by deformation equations Hall shows that free development leads to crystal with 1-3 urchin structure less deformed than crystal with 0-3 porous sphere. The obtained SnO2with 1-3 urchin possesses a high specific surface area of 61 m 2 /g and rather higher than some hierarchical nanotructures assembled from 1D and 2D. 3. SnO 2with 0-1 MCM-41 structure with highly ordered mesopore, high tin oxide content has been synthesized by direct methods. Tin oxide introduced into MCM-41 exists in two major forms: (i). tetrahedral and octahedral coordinated tin join to the silica wall inthe framework, (ii). hexacoordinated polymeric Sn–O–Sn type species to forms tin oxide clutters. Their size is too small to observeby XRD. Formation mechanism SnO2 with 0-1 MCM-41 depends on the synthesis conditions as proposed schemes 3.3. This mechanism shows that tin oxide can be dispersed onto the framework with highly ordered mesopore and high tin oxide content by appropriately adjusting the molar ratio Sn/Si and NaOH concentration. </p>

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