Alumina-supported CuO–CeO₂–ZrO₂Catalysts for CO Oxidation – Preparation and Characterization

Abstract

The effect of catalyst samples, prepared by different methods, having the composition (CuCe 5.17 Zr 3.83 O x /γ-Al 2 O 3 (20 wt%) was studied in the present work for carbon monoxide (CO) oxidation. Cu(NO 3 ) 2 3H 2 O was used as a precursor for the preparation of the catalysts. Catalysts were prepared by four methods: co-impregnation, citric acid sol-gel, urea nitrate combustion and urea gelation co-precipitation methods. Prepared catalysts were characterized by BET specific surface area, X-ray diffraction, thermogravimetic analysis/differential scanning calorimetry (TGA/DSC) and scanning electron microscopy (SEM) techniques. The oxidation of CO was carried out in a tubular fixed bed reactor at atmospheric pressure and at temperature ranging from ambient to 250°C. A fixed weight (100 mg) of the catalyst was taken and 2.5% CO in air at a total feed rate of 60 ml/min was used in the reactor. It was observed that the performance of the catalysts in CO oxidation was influenced by the preparation methods. The catalyst prepared by sol-gel method that calcined at 500°C exhibited excellent activity for CO oxidation with total conversion at 210°C. The ranking order of the alumina supporting CuO-CeO 2 -ZrO 2 catalysts was as follows: sol-gel > co-impregnation > urea gelation > urea nitrate combustion. The four catalysts prepared did not show deactivation of catalytic activity for 50 h of continuous runs.

Status of Micronutrients in Mixed Red and Black Soils of Rewa District of Madhya Pradesh, India

“…Indiscriminate use of high analysis chemical fertilizers results in the deficiency of secondary and micronutrients in soils 1 . Variability in micronutrient contents of the soils is a mirror of the diversity in parent materials from which these have originated 2 . Information about the extent of micronutrient deficient area is necessary for the scientists, administrators, farmers and fertilizer manufacturers to determine the kind and quantity of fertilizer required for the particular region.…”