New Nanocrystalline Cu/MnO_x Catalysts Prepared from Supercritical Antisolvent Precipitation

Abstract

Supercritical CO2 is used as an antisolvent to precipitate out nanostructured homogeneous mixtures of Cu2+ and Mn3+ with crystallites of 10–20 nm in diameter. Following calcination, this material forms a crystalline tetragonal spinel, CuMn2O4, with a branched chainlike structure with a length of 160–200 nm and diameters of approximately 40 nm. This new material is more than twice as active per unit surface area as the conventionally prepared hopcalite catalysts for the oxidation of carbon monoxide. This is the first time that homogeneous mixed oxides have been formed using this method.

Effect of Preparation Conditions on the Catalytic Activity of CuMnOx Catalysts for CO Oxidation

“…The percentage of CO oxidation is shown in Figure 11. With the increasing calcination temperature of the precursor, the catalytic activity is increasing, and it could be observed before reached to 300 o C temperature [15].…”

“…A lot of interest has been given to modification of the CuMnOx catalyst to remove its faults of moisture for deactivation and lower activity [15,16]. The optimization in CuMnOx catalyst during the preparation conditions like drying temperature, drying time, calcination temperature, calcination time and the molar ratio of Copper/Manganese (Cu:Mn) have improved the performance of CuMnOx catalysts for lowtemperature CO oxidation [17].…”

Vanadium Phosphate Materials as Selective Oxidation Catalysts

“…Hutchings and coworkers (78)(79)(80)(81)(82)(83) pioneered the use of supercritical antisolvent precipitation to prepare a number of catalyst and support materials including vanadium phosphates. Vanadium phosphate precursor solutions were prepared from VOCl 3 and H 3 PO 4 refluxed in isopropanol.…”

Study of Hopcalite (CuMnOx) Catalysts Prepared Through A Novel Route for the Oxidation of Carbon Monoxide at Low Temperature

“…These include firefighting and mining [2] in the form of breathing apparatus. The three-fourth of all the hydrocarbons and CO are emitted during, a test run of the car in Cold-start conditions [3].…”