Papers by Author: Yuki Yamasaki

Abstract: Dense mesoporous alumina bulks were successfully synthesized by a hydrothermal hot-pressing (HHP) method for mesoporous alumina powders prepared as starting material with a high BET surface area and narrow pore size distribution. As a result, mesoporous alumina HHP bulks had high density with uniformity pore size distribution and a high specific surface area. Their microstructural features for dense mesoporous alumina bulks were observed by SEM. The characterization of mesopores was examined.

Abstract: In this study, the synthesis of the bulky and dense mesoporous silica such as FSM was attempted by a hydrothermal hot-pressing (HHP) with a surfactant as a template and a subsequent calcination. According to TEM observation, the dense bulks obtained by HHP had a hexagonal mesopore structure. Also, these dense FSM bulks possessed high specific surface areas. Furthermore, Ag-supported dense FSM bulks were successfully synthesized by HHP with Ag salt and a subsequent calcination in H2. Thus, this HHP method is useful for synthesizing dense bulks and simultaneous supporting novel metals such as Ag on bulky FSM.

Abstract: In this study, the synthesis of nanotubular titanate was attempted though heat-treatment in an oil bath (non-hydrothermal treatment), heat-treatment with stirring in an oil bath (non-hydrothermal treatment), or hydrothermal treatment for metal Ti in NaOH aqueous solution systems. Obtained products were characterized by various methods, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD results suggested that products obtained by both hydrothermal treatment and heat-treatment in an oil bath with and without stirring could be identified as H2Ti4O9
H2O. From TEM observations, however, various morphologies for products obtained by these treatments were confirmed. Therefore, it was considered that morphologies of these products strongly depended on synthesis conditions.

Abstract: Synthesis of bulky Y-zeolite was attempted by a hydrothermal hot-pressing (HHP) method. These bulky products synthesized under hydrothermal conditions were identified as Y-zeolite single phase. Especially, bulky Y-zeolite having translucency, high density and large surface area was obtained by HHP treatment at 423K for 2h with 17wt% of 5M-NaOH solution. This solidified zeolite like single-crystal was considered to be made by dissolution and precipitation mechanism. High-density bulky zeolites can be expected as novel molecular sieves and catalysts with high activity.