Pd/SiO2 catalysts: synthesis of Pd nanoparticles with the controlled size in mesoporous silicas
Synthesis of Pd nanoparticles with controlled size (d(Pd) = 1-3.6 nm) was carried out within the pores of the mesoporous HMS and SBA-15 silicas. Pd was ion-exchanged on non-calcined silicas, prepared by solvent extraction of the templates. A high concentration of silanol groups on the mesopore surface allowed attaining Pd loading up to 4.4. wt.%. The Pd/HMS and Pd/SBA-15 were characterised by chemical analysis, XRD, N2 adsorption-desorption and transmission electron microscopy (TEM) methods. The materials possess a high SSA and narrow pore size distribution. Introduction of Pd nanoparticles in HMS resulted in a progressive loss of the regularity in the mesoporous structure. On the contrary, all Pd/SBA-15 composites retained the original well-ordered 2D hexagonal structure of SBA-15. The thick walls of the SBA-15 framework are accounted for the higher stability observed. The TEM investigations confirmed that the Pd nanocrystals were located within the SBA-15 mesoporous framework channels. The particle size did not exceed the mesopore diameter (2-6 nm) at Pd loading of 0.1-4.4wt.%. Pd clusters were found to be resistant against sintering during air-calcination (550 degreesC, 4h). The catalyst 2.1%Pd/SBA-15 used in methane combustion at 520 degreesC demonstrated stable activity during 6h on stream.
Keywords: Combustion catalysts; Nanoparticles (Pd/SiO2 catalysts: ; synthesis of Pd nanoparticles with the controlled size in ; mesoporous silicas) ; methane combustion catalyst palladium nanoparticle ; mesoporous silica
CAN 138:290089 51-12 Fossil Fuels, Derivatives, and Related Products LGRC,Swiss Federal Institute of Technology,Lausanne,Switz. Journal 1381-1169 written in English. 7440-05-3 (Palladium); 7631-86-9 (Silica) Role: CAT (Catalyst use), USES (Uses) (Pd/SiO2 catalysts: synthesis of Pd nanoparticles with the controlled size in mesoporous silicas); 74-82-8 (Methane) Role: CPS (Chemical process), PEP (Physical, engineering or chemical process), PROC (Process) (Pd/SiO2 catalysts: synthesis of Pd nanoparticles with the controlled size in mesoporous silicas)
Record created on 2006-04-18, modified on 2016-08-08