Preparation Of KIT-6by Partitioned Coopeartive Self-assembly Process And Mesoporous Ni By Nanocasting Method

A kind of mesoporous silica material(KIT-6) with bi-continuous cubic mesostructure of Ia3d symmetry and interpenetrating cylindrical pore system, prepared utilizing Pluronic P123tri-block copolymer(EO2oPO70EO20) and n-butanol mixtures for the structure direction in aqueous solution. It possesses high specific surface areas, high pore volumes and very narrow distribution of pore diameters and thus attracted a great deal of interest for its potential application in various areas, including biological engineering, chemical engineering,medicine and energy, etc.Unfortunately, so far the reports on the tuning of the mesostructures or other physical properties of KIT-6are rather limited due to the narrow proportion of raw materials and hard controling the mesostructures of conventional cooperative self-assembly process of KIT-6. So, a new synthesis route of KIT-6is proposed, called partitioned cooperative self-assembly process (PCSA). It is a facile and versatile synthesis method allowing the physical properties of mesoporous materials to be adjusted by simply partitioning the addition combinations of precursors without using any additives or special synthetic conditions.In this work, using tetraethoxysilane (TEOS) and low-cost, nontoxic sodium silicate (Na2SiO3) as silica precursors, we applied PCSA method to synthesize KIT-6, studied the variations of the mesostructres and physical properities of KIT-6with different addition combinations, different interval times of precursor and different hydrothermal temperatures in PCSA conditions. The results show that:(1) PCSA based on TEOS:Cubic Ia3d mesostructure KIT-6can be synthesized by PCSA method; The unit cell parameters of KIT-6by PCSA method are normally larger than those by conventional method, with controllable mesopore sizes of8-10nm by varying addition combinations or interval times; When hydrothermal aging temperature is140℃, well KIT-6mesostructure can still be obtained by PCSA method, while the mesostructure deteriorates noticeably by conventional method; The particle sizes of KIT-6can be significantly reduced from sub-millimeter to several microns via the PCSA process compared with those prepared via the conventional method.(2) PCSA based on Na2SiO3:Using Na2SiO3as silica precursor, cubic Ia3d mesostructure KIT-6can be synthesized by PCSA method,but attention interval combinations and times; The mesopore sizes of KIT-6by PCSA method are larger than those by conventional method; Comapred with KIT-6by conventional method, mesopore volumes of KIT-6by PCSA process increased and micropore volume shows an inverse trend. The mesostructures of KIT-6often get deteriorated with increasing hydrothermal aging temperature, while the KIT-6prepared by PCSA process can sustain to a great extent.(3) As an extension to the work on KIT-6, nickel replicas can be obtained by nanocasting method using nickel citrate as the nickel precursor and KIT-6or the other typical mesoporous silica SBA-15as hard templates.