Journal
ACS CATALYSIS
Volume 8, Issue 11, Pages 10383-10391Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acscatal.8b03435
Keywords
charged enhanced dry impregnation (CEDI); electrostatic adsorption; catalyst preparation; particle size; Pt; Pd; Co; Ni
Categories
Funding
- University of South Carolina Smartstate Center of Catalysis for Renewable Fuels
Ask authors/readers for more resources
In this work charge enhanced dry impregnation (CEDI), a hybrid method of supported nanoparticle synthesis which combines the advantages of electrostatic adsorption small particle size and tight size distributions with the simplicity of incipient wetness impregnation, is demonstrated for four different metals (Pt, Pd, Co, and Ni) at multiple metal loadings over a common silica support. CEDI is achieved by basifying the impregnating solution sufficiently to charge the silica surface at the condition of incipient wetness. The electrostatic interactions induced between cationic ammine metal precursors and the deprotonated, negatively charged support result in smaller nanoparticles with tighter size distribution in comparison to those for incipient wetness impregnation (or dry impregnation, DI) with no pH adjustment. The method works best when the balancing ion of the precursor salt is hydroxide, such as platinum tetraammine hydroxide, (NH3)(4)Pt(OH)(2). Using the corresponding chloride salts with CEDI results in larger metal particles, but these are still smaller than DI-derived particles. Washing out the chloride results in very small nanoparticles without appreciable metal loss at metal loadings corresponding to one monolayer of precursor or below. Ammine complexes with nitrate as the counterion give small nanoparticles at lower but still relevant metal loadings (1 or 2 wt %) with no washing; in this way the CEDI synthesis procedure is completely parallel to incipient wetness impregnation but gives much better metal dispersion.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available