Padigapati S. Reddy

Catalytic decomposition of CH4 over Ni-Al2O3-SiO2 catalysts: Influence of pretreatment conditions for the production of H2

Abstract This article reports the production of CO x free hydrogen and carbon nanofibers by the catalytic decomposition of methane over Ni-Al 2 O 3 -SiO 2 catalysts. The influence of reaction temperature, pretreatment temperature, and effect of reductive pretreatment on the decomposition of methane activity is investigated. The physico-chemical characteristics of fresh and deactivated samples were characterized using BET-SA, XRD, TPR, SEM/TEM, CHNS analyses and correlated with the methane decomposition results obtained. The Ni-Al-Si (4:0.5:1.5) catalyst reduced with hydrazine hydrate produced better H 2 yields of ca . 1815 mol H 2 /mol Ni than the catalyst reduced with 5% H 2 /N 2 .

Selective Gas-Phase Conversion of Glycerol to Acetol Over Promoted Zirconia Solid Acid Catalysts

The vapour phase selective conversion of glycerol to acetol at normal atmospheric pressure in a fixed-bed micro reactor was investigated over SO4 2� and WOx promoted ZrO2 and M-ZrO2 (M = Al2O3 or TiO2) solid acid catalysts. The investigated sulfate and tungstate ion promoted zirconia-based catalysts were prepared by both coprecipitation and impregnation methods and calcined at 923 K. The synthesized catalysts were characterized by means of X-ray powder diffraction, X-ray photoelectron spectroscopy, BET surface area and ammonia temperature-programmed desorption methods. Characterization results suggest that SO4 2� promoter strongly influences the physicochemical properties of the support oxides than WOx. However, the WOx promoted catalysts exhibited better catalytic activity than SO4 2� promoted catalysts. Among various catalysts investigated, the WOx/Al2O3-ZrO2 catalyst exhibited stable catalytic activity with the highest glycerol conversion of 99% and acetol selectivity of 74%.

Hydrogenolysis of bioglycerol to 1,2-propanediol over Ru/CeO2 catalysts: influence of CeO2 characteristics on catalytic performance

Abstract Hydrogenolysis of glycerol to 1,2-propanediol is an alternative route for efficient utilization of biomass-derived glycerol to value-added chemicals. In this study, catalytic hydrogenolysis of glycerol was systematically investigated over various Ru/CeO2 catalysts. CeO2-support was prepared by different methods and Ru deposition by wet impregnation method. Synthesized catalysts were characterized by various techniques, namely, XRD, XPS, TPR, TPD, and other. Hydrothermally synthesized CeO2-supported Ru catalyst showed relatively more number of acid sites with mild acid strength and exhibited highest conversion and product selectivity. Effect of various parameters including Ru loading, reaction temperature, and hydrogen pressure was evaluated and addressed.