Characterization and catalytic activity of soft-templated Ni0-CeO_(2) mixed oxides for CO and CO_(2) co-methanation  

作　　者：Luciano Atzori Maria Giorgia Cutrufello Daniela Meloni Barbara Onida Delia Gazzoli Andrea Ardu Roberto Monaci Maria Franca Sini Elisabetta Rombi 

机构地区：[1]Department of Chemical and Geological Sciences,University of Cagliari,09042 Monserrato(CA),Italy [2]Department of Materials Science and Chemical Engineering,CR-INSTM for Materials with Controlled Porosity,Polytechnic of Turin,10129 Turin,Italy [3]Department of Chemistry,University of Rome“La Sapienza”,00185 Rome,Italy

出　　处：《Frontiers of Chemical Science and Engineering》2021年第2期251-268,共18页化学科学与工程前沿（英文版）

基　　金：Open Access funding provided by Universita degli Studi di Cagliari.

摘　　要：Nanosized NiO,CeO_(2) and NiO-CeO_(2) mixed oxides with different Ni/Ce molar ratios were prepared by the soft template method.All the samples were characterized by different techniques as to their chemical composition,structure,morphology and texture.On the catalysts submitted to the same reduction pretreatment adopted for the activity tests the surface basic properties and specific metal surface area were also determined.NiO and CeO_(2) nanocrystals of about 4 nm in size were obtained,regardless of the Ni/Ce molar ratio.The Raman and X-ray photoelectron spectroscopy results proved the formation of defective sites at the NiO-CeO_(2) interface,where Ni species are in strong interaction with the support.The microcalorimetric and Fourier transform infrared analyses of the reduced samples highlighted that,unlike metallic nickel,CeO_(2) is able to effectively adsorb CO_(2),forming carbonates and hydrogen carbonates.After reduction in H2 at 400°C for 1 h,the catalytic performance was studied in the CO and CO_(2) co-methanation reaction.Catalytic tests were performed at atmospheric pressure and 300°C,using CO/CO_(2)/H_(2) molar compositions of 1/1/7 or 1/1/5,and space velocities equal to 72000 or 450000 cm^(3)∙h^(-1)∙gcat^(-1).Whereas CO was almost completely hydrogenated in any investigated experimental conditions,CO_(2) conversion was strongly affected by both the CO/CO_(2)/H_(2) ratio and the space velocity.The faster and definitely preferred CO hydrogenation was explained in the light of the different mechanisms of CO and CO_(2) methanation.On a selected sample,the influence of the reaction temperature and of a higher number of space velocity values,as well as the stability,were also studied.Provided that the Ni content is optimized,the NiCe system investigated was very promising,being highly active for the CO_(x) co-methanation reaction in a wide range of operating conditions and stable(up to 50 h)also when submitted to thermal stress.

关 键 词：soft template method Ni0-CeO_(2)catalystss CO and CO_(2)co-mtharation synthetic natural gas production 

分 类 号：O64[理学—物理化学]