Characterization of platinum-iron catalysts supported on MCM-41 synthesized with rice husk silica and their performance for phenol hydroxylation

Jitlada Chumee; Nurak Grisdanurak; Arthit Neramittagapong; Jatuporn Wittayakun

doi:10.1088/1468-6996/10/1/015006

Characterization of platinum-iron catalysts supported on MCM-41 synthesized with rice husk silica and their performance for phenol hydroxylation

Sci Technol Adv Mater. 2009 Mar 4;10(1):015006. doi: 10.1088/1468-6996/10/1/015006. eCollection 2009 Feb.

Authors

Jitlada Chumee¹, Nurak Grisdanurak², Arthit Neramittagapong³, Jatuporn Wittayakun⁴

Affiliations

¹ Material Chemistry Research Unit, School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
² Department of Chemical Engineering, Thammasat University, Pathumthani 12120, Thailand; Center of Environmental and Hazardous Waste Management (EHWM), Thammasat University, Pathumtani 12120, Thailand.
³ Department of Chemical Engineerng, Khon Kaen University, Khon Kaen 40002, Thailand.
⁴ Material Chemistry Research Unit, School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand; Center of Environmental and Hazardous Waste Management (EHWM), Thammasat University, Pathumtani 12120, Thailand.

Abstract

Mesoporous material RH-MCM-41 was synthesized with rice husk silica by a hydrothermal method. It was used as a support for bimetallic platinum-iron catalysts Pt-Fe/RH-MCM-41 for phenol hydroxylation. The catalysts were prepared by co-impregnation with Pt and Fe at amounts of 0.5 and 5.0 wt.%, respectively. The RH-MCM-41 structure in the catalysts was studied with x-ray diffraction, and their surface areas were determined by nitrogen adsorption. The oxidation number of Fe supported on RH-MCM-41 was + 3, as determined by x-ray absorption near edge structure (XANES) analysis. Transmission electron microscopy (TEM) images of all the catalysts displayed well-ordered structures, and metal nanoparticles were observed in some catalysts. All the catalysts were active for phenol hydroxylation using H₂O₂ as the oxidant at phenol : H₂O₂ mole ratios of 2 : 1, 2 : 2, 2 : 3 and 2 : 4. The first three ratios produced only catechol and hydroquinone, whereas the 2 : 4 ratio also produced benzoquinone. The 2 : 3 ratio gave the highest phenol conversion of 47% at 70 °C. The catalyst prepared by co-impregnation with Pt and Fe was more active than that prepared using a physical mixture of Pt/RH-MCM-41 and Fe/RH-MCM-41.

Keywords: MCM-41; bimetallic catalysts; iron; phenol hydroxylation; platinum; rice husk.