Hydrogen Spillover Effect of Pt-Doped Activated Carbon Studied by Inelastic Neutron Scattering


We employed the inelastic neutron scattering (INS) method to directly monitor the change of molecular hydrogen in the Pt-doped activated carbon (Pt/AC) samples and provide very conclusive evidence that significant hydrogen atoms can diffuse to the carbon surface at room temperature during the spillover process. The INS method is uniquely capable of revealing the state of the hydrogen (either the atomic or molecular form). The INS result shows a direct quantitative evaluation of the amount of hydrogen adsorbed on AC in an atomic form via spillover. Two Pt/AC samples with different spillover effects were studied herein. The spillover behavior related to dissociation, diffusion, and adsorption of hydrogen in the Pt/AC samples at the temperature cycling from 4 up to 300 K was investigated by this INS study. The present study proposes the concept of diffusion length and hydrogen-rich domain around a Pt cluster center in this system based on INS data.


Chemical and Biochemical Engineering


United States. Department of Energy
United State Department of Commerce. National Institute of Standards and Technology
National Synchrotron Radiation Research Center (Taiwan, Republic of China)


The research at MIT is supported by DOE Grant No. DE-FG02-90ER45429. We thank the NIST Center for Neutron Research for the allocation of neutron beam time in BT4- FANS. The research at the University of Delaware is partly supported by the cooperative agreement 70NANB7H6178 from NIST, U.S. Department of Commerce. C.-S.T. thanks the travel grant (NSC 99-2739-M-213-001) from the National Synchrotron Radiation Research Center, Taiwan, ROC.

Keywords and Phrases

Carbon surface; Diffusion length; Hydrogen atoms; Hydrogen spillover; Molecular hydrogen; Pt clusters; Quantitative evaluation; Room temperature; Spillover effects; System-based; Temperature cycling; Activated carbon; Atoms; Hydrogen; Inelastic neutron scattering; Platinum; Platinum compounds; Gas adsorption

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Article - Journal

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© 2011 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Aug 2011