Catalytic Behaviour of Mesoporous Cobalt-Aluminum Oxides for CO Oxidation

Ankur Bordoloi,Heshmat Noei,Martin Muhler,Dennis Großmann,Miguel Sanchez,Wolfgang Grünert,Stefan Kaluza,Yuemin Wang

doi:10.1155/2014/807545

Abstract

Ordered mesoporous materials are promising catalyst supports due to their uniform pore size distribution, high specific surface area and pore volume, tunable pore sizes, and long-range ordering of the pore packing. The evaporation-induced self-assembly (EISA) process was applied to synthesize mesoporous mixed oxides, which consist of cobalt ions highly dispersed in an alumina matrix. The characterization of the mesoporous mixed cobalt-aluminum oxides with cobalt loadings in the range from 5 to 15 wt% and calcination temperatures of 673, 973, and 1073 K indicates that Co2+ is homogeneously distributed in the mesoporous alumina matrix. As a function of the Co loading, different phases are present comprising poorly crystalline alumina and mixed cobalt aluminum oxides of the spinel type. The mixed cobalt-aluminum oxides were applied as catalysts in CO oxidation and turned out to be highly active.

Highlights

Supported metal oxide catalysts have attracted much attention in recent years due to their widespread applicability in industrially and academically important reactions
Continuous efforts have been made in the last few decades by several groups [5,6,7] to synthesize porous alumina with high surface area by high-temperature dehydration of bulk powders [8], modified sol-gel synthesis in the presence of organic moieties [9, 10], different surfactants [3], block copolymers [11,12,13,14], or evaporation-induced self-assembly (EISA) with colloidal precursors and amine structural agents [15, 16]
X-ray photoelectron spectroscopy (XPS) measurements were carried out in an ultra-high vacuum (UHV) setup equipped with a monochromatic Al Kα X-ray source (h] = 1486.6 eV) operated at 14.5 kV and 35 mA and a highresolution Gammadata-Scienta SES 2002 analyzer

Summary

Introduction

Supported metal oxide catalysts have attracted much attention in recent years due to their widespread applicability in industrially and academically important reactions. Continuous efforts have been made in the last few decades by several groups [5,6,7] to synthesize porous alumina with high surface area by high-temperature dehydration of bulk powders [8], modified sol-gel synthesis in the presence of organic moieties [9, 10], different surfactants [3], block copolymers [11,12,13,14], or evaporation-induced self-assembly (EISA) with colloidal precursors and amine structural agents [15, 16] These materials represent an active support, which may participate positively or negatively in the formation of the final catalysts. As a first catalytic test reaction to monitor the redox properties, the mixed metal oxides were applied in CO oxidation

Experimental

Results and Discussion

Conclusions