화학공학소재연구정보센터
Catalysis Today, Vol.356, 122-131, 2020
Enhancement of selectivity in methanol oxidation over copper containing SBA-15 by doping with boron species
The aim of this study was to prepare and characterize the bifunctional catalysts containing copper (redox source) and boron (acidity source) loaded on SBA-15 for catalytic methanol oxidation. Copper and boron species were loaded by sequential impregnation or co-impregnation, and three series of materials were prepared: series Cu-xB with copper loaded prior to boron, series xB-Cu with boron loaded prior to copper, and series xBCu with copper and boron co-impregnated (x designated B/Cu molar ratio; x = 0.5, 1 and 3). The materials were characterized by XRD, N-2 physisorption, XPS, UV-vis spectroscopy, and combined H-2-TPR/N2O oxidation analysis and were also investigated by test reactions of 2-propanol decomposition and pyridine adsorption combining with FTIR. The results showed that the strength of the interaction between copper and boron was depended on the sequence of incorporation, and that the materials contained only Lewis acid sites with acidity strength weakened with increasing boron amount. The roles of preparation procedure, content of boron, strength of interaction between boron and copper species, strength and number of Lewis acid sites were considered in the context of activity and selectivity in methanol oxidation. The series xB-Cu catalysts showed higher activity for the oxidation of methanol than other two series, and for xB-Cu catalysts the addition of boron lowered the reducibility of copper oxides. The best catalyst was found to be 1B-Cu, which exhibited relatively high activity, high selectivity to methyl formate and formaldehyde, and high stability.