Preparation of Mesoporous Clay Complex by Ticl4 Treated with Nh4oh for Selective Catalytic Reduction
Hee Je Seong, Joon Ho Ko, and Hee Sung Yang. Energy & Environment Research Department, Hyundai Heavy Industries Co., Ltd., 1, Cheonha-Dong, Dong-Ku, Ulsan, South Korea
The pillared interlayered clays intercalated by titania (Ti-PILC) has been widely studied as a promising catalyst support to replace the conventional titania. From our previous characterization and activity tests for Ti-PILC, the pore size of Ti-PILC tends to be smaller and vanadia supported catalyst showed less NO removal activity of selective catalytic reduction with increasing synthetic scale. To overcome those problems, we developed a new catalyst support as an alternative of Ti-PILC by using easy and efficient method comparing with Ti-PILC. The gel-like material was prepared by reaction of titanium tetrachloride (TiCl4) solution with ammonium hydroxide and then, it was added to clay slurry. After overnight, the slurry was filtered and a new mesoporous support was obtained through drying and calcining at 350°C. It was characterized by BET, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The XRD results indicate that the new support is similar to the conventional Ti-PILC in diffraction patterns but anatase titania peak is more apparent. The TiO2, Al2O3 and SiO2 contents of both supports are similar but Ti atomic ratio of the support is smaller than that of Ti-PILC from XPS analysis. The mean particle size is assumed to be 95" from HR-TEM while that of Ti-PILC is 50", which is well matching with the results for primary pore size from BET. And also, EDX through TEM showed Ti, Al and Si are well dispersed on the surface of both supports. The material made from the reaction of TiCl4 solution and ammonium hydroxide was elucidated as amorphous state in drying condition and it is crystallized with rising temperature. From these results, this amorphous material is presumed to be absorbed into swollen clay like intercalation process of Ti4+ in Ti-PILC. Consequently, the properties of this new support are similar to those of Ti-PILC in many aspects. By comparison, a new catalyst impregnated with vanadia exhibits 60% more SCR catalytic activity than V2O5-Ti-PILC. So, we expect this new material can be a promising support for an alternative of TiO2 applicable to other catalytic processes.