Fabrication of porous titanium dioxide assisted by resorcinol/formaldehyde gel

Abstract

Incorporation of titania into RF solution, which was prepared via the sol-gel polycondensation of resorcinol and formaldehyde using acetic acid as catalyst, was investigated. Titanium tetraisopropoxide (TTIP) was used as precursor for titania. The reaction between titania precursor and RF solution is quite violent and strongly exothermic therefore titania sol is separately prepared for slowing down the reaction. Titania sol was firstly prepared from TTIP via sol-gel process. After certain period of aging time, the titania sol was added into RF mixture, which had been aged for predetermined period of time as well. After that, the mixture was further aged for another 36 hours before being dried at 80°C. Finally, the dried gel was calcined at 500°C for 4 hours to remove the RF template. From result, when titania sol is added into RF solution, titania sol reacts with RF solution to form clusters. This reaction is witnessed by the increase in the signal of Ti-O-C. The product is developed from micropore to mesopore by using RF template. In addition, higher of R/F and R/C ratio is affected on the reaction between RF gel and titania sol and then, the final product is high surface area. Amount of titania also affects on surface area and mesoporous of the product. The period of RF and titania aging time results in the formation of network, which prohibits complete reaction between titania sol and RF solution. However, reaction between RF/titania takes place while RF gel and titania sol are formed into cross-linked of RF gel as well as the cross-linking of titania sol.