Improved Stability of Pd/Al2O3 Prepared from Palladium Nanoparticles Protected with Carbosilane Dendrons in the Dimethyl Ether Steam Reforming Reaction

• Published in: ChemCatChem 2015-07, Vol.7 (14), p.2179-2187
• Main Authors: Ramos, Erika, Davin, Laia, Angurell, Inma, Ledesma, Cristian, Llorca, Jordi
• Format: Article
• Language: English
• Subjects: Catalysis; Catàlisi; Dendrimers; Energies; Enginyeria química; Heterogeneous catalysis; Hidrogen com a combustible; Hydrogen; Hydrogen as fuel; Nanoparticles; Nanopartícules; Palladium; Química física; Supported catalysts; Àrees temàtiques de la UPC
• ISSN: 1867-3880; 1867-3899
• DOI: 10.1002/cctc.201500202

The dimethyl ether steam reforming reaction to generate hydrogen was tested over 1 wt % Pd/Al2O3 catalysts prepared from different precursors. The conventional catalyst prepared by incipient wetness impregnation from palladium nitrate underwent strong deactivation under reforming conditions at 823 K because of metal sintering and carbon deposition. The same occurred over the catalyst prepared from preformed Pd nanoparticles protected with dodecanethiol. In contrast, catalysts prepared from Pd nanoparticles protected with carbosilane dendrons showed enhanced stability and good performance for the production of hydrogen. This was because of the formation of SiO2 at the Pd–Al2O3 interface that acted as a pinning center and prevented Pd migration under the reaction conditions as well as the accumulation of carbon. Reform with a tree‐form: Pd/Al2O3 catalysts prepared from preformed Pd nanoparticles protected with carbosilane dendrons show an outstanding stability for the steam reforming of dimethyl ether compared to conventional catalysts. Upon calcination, the protecting shell decomposes and leaves the Pd nanoparticles anchored to the support in contact with SiO2, which prevents metal sintering under reaction conditions and carbon accumulation.