One-Pot synthesis of phosphorylated mesoporous carbon heterogeneous catalysts with tailored surface acidity

Journal Article · Sun Jan 01 00:00:00 EST 2012 · Catalysis Today

DOI:https://doi.org/10.1016/j.cattod.2011.08.004· OSTI ID:1042863

Fulvio, Pasquale F ^[1]; Mahurin, Shannon Mark ^[1]; Mayes, Richard T ^[1]; Bauer, Christopher ^[1]; Wang, Xiqing ^[1]; Veith, Gabriel M ^[1]; Dai, Sheng ^[1]

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1. ORNL

Soft-templated phosphorylated mesoporous carbons with homogeneous distributions of phosphate groups were prepared by a 'one-pot' synthesis method using mixtures of phosphoric acid with hydrochloric, or nitric acids in the presence of Pluronic F127 triblock copolymer. Adjusting the various ratios of phosphoric acid used in these mixtures resulted in carbons with distinct adsorption, structural and surface acidity properties. The pore size distributions (PSDs) from nitrogen adsorption at -196 C showed that mesoporous carbons exhibit specific surface areas as high as 551 m{sup 2}/g and mesopores as large as 13 nm. Both structural ordering of the mesopores and the final phosphate contents were strongly dependent on the ratios of H{sub 3}PO{sub 4} in the synthesis gels, as shown by transmission electron microscopy (TEM), X-ray photoelectron (XPS) and energy dispersive X-ray spectroscopy (EDS). The number of surface acid sites determined from temperature programmed desorption of ammonia (NH{sub 3}-TPD) were in the range of 0.3-1.5 mmol/g while the active surface areas are estimated to comprise 5-54% of the total surface areas. Finally, the conversion temperatures for the isopropanol dehydration were lowered by as much as 100 C by transitioning from the least acidic to the most acidic catalysts surface.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1042863
• Journal Information: Catalysis Today, Vol. 186, Issue 1; ISSN 0920-5861
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ADSORPTION
AMMONIA
CARBON
CATALYSTS
DEHYDRATION
DESORPTION
MIXTURES
NITRIC ACID
NITROGEN
PH VALUE
PHOSPHATES
PHOSPHORIC ACID
PHOSPHORYLATION
PLURONICS
SPECIFIC SURFACE AREA
SURFACE AREA
SYNTHESIS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY PHOTOELECTRON SPECTROSCOPY
X-RAY SPECTROSCOPY