1 Unité de catalyse et de chimie des matériaux divisés, Université catholique de Louvain Croix du Sud 2/17, 1348 Louvain-la-Neuve (Belgium) – * ; FNRS Research An innovative preparation of heterogeneous metal nanoparticles catalysts for VOC abatement: the onion-type multilamellar vesicles route [1] D.P. Debecker 1 *, C. Faure 2, M.-E. Meyre 2, A. Derré 2 and E.M. Gaigneaux 1 2 Centre de Recherche Paul Pacal (CNRS), Université de Bordeau 1 Avenue du Dr. Albert Schweitzer, Pessac, France CONCLUSION 1. Transfer of onion-grown Ag nanoparticles onto an inorganic support: easy and quantitative 2. In situ burning of the surfactant leads to: accessible catalyst surface and active catalyst 3. Relative stability vs. sintering 4. Potential application with nanoparticles of various nature, form, size, density, etc TiAgCV ӨAgT_D na ӨAgT_E na ӨAgTV_E TiO 2 (%)Ag (%)V 2 O 5 (%)Mass balance (%) ӨAgT_Dmeasured Expected ӨAgT_EMeasured Expected ӨAgTV_EMeasured Expected Ti (%)Ag (%)C (%)O (%)N (%)Ag/TiC/TiN/Ti ӨAgT_D ӨAgT_D Calcined [1] D.P. Debecker et al., Small, In Press [2] S. Eriksson et al. Appl. Catal., A 265 (2004) 207 [3] C. Faure, et al. J. Phys. Chem.107 (2003) 4738 Adherence, accessibility, activity and stability of supported Ag nanoparticles Quantitative transfer of Onion-grown Ag nanoparticles onto TiO 2 support (‘T’) and V 2 O 5 /TiO 2 (‘TV’) catalyst. surfactant + water is sheared in vials with a spatula to form onions. AgNO 3 is introduced by encapsulation (at the shearing step, denoted ‘E’) or by diffusion into preformed onions (denoted ‘D’) TEM: aggregate of Ag nanoparticles-loaded onions Chemical analysis (ICP-AES) XPS surface analysis Most of the surfactant is burned out at ~320°C Small particles still adhere on TiO2 after calcination Surface C and N (from the surfactant) concentrations drop Ti, O, Ag concentrations increase (accessibility of inorganic surface) TG analysis of Ag nanoparticle loaded onion TEM: Ag nanoparticles grown in onions and impregnated on TiO 2 particles After incubationAfter impregnation Left: diffusion (D) ~10 nm Right: encapsulation (E) ~5 nm XPS surface analysis High carbon surface concentration Excess of Ag in ‘D’ preparation Low Ag load in ‘E’’ preparation XPS: Ag 3d peak Experimental composition closely fits the expected values The surfactant account for less than 5% of the total dry weight After calcination (320°C, air) TEM: calcined catalyst Activity measurements in benzene total oxidation (C 6 H 6 :O 2 100ppm:20% in He ; 200 ml/min ; 200 mg of catalyst in fixed bed reactor TiO 2 (T) = poorly active AgT catalyst: First run <350°C: less active (surfactant covering ; inaccessible surface >300°C: increase of activity (Ag nanoparticles work in the reaction) AgT catalyst: Second run Accessible surface ; (smaller) effect of Ag from 350°C. V 2 O 5 /TiO 2 (TV) = very active VOC catalyst AgTV catalyst: First run <300°C: less active (surfactant covering ; inaccessible surface °C: total conversion : no effect of Ag AgTV catalyst: Second run Accessible surface ; synergistic effect between V 2 O 5 and Ag at 250°C Activity measurements in benzene total oxidation (C 6 H 6 :O 2 100ppm:20% in He ; 200 ml/min ; 200 mg of catalyst in fixed bed reactor RESULTS INTRODUCTION Chemical reactions demand metal-based catalysts with small, stable and tailored nanoparticles [2] industrial and fundamental interest Limitation of classical preparation method: need of thermal treatmentduring which sintering is hardly controlled deactivation, loss of selectivity, etc. [2] Production of tailored metal nanoparticle at ambient t° inside organic onion-type vesicles [3] used in the preparation of solid catalysts ! Interest Constraint New idea STRATEGY