Final Report: Characterization of Hydrogen Adsorption in Carbon-Based Materials by NMR

PDF Version Also Available for Download.

Description

In support of DOE/EERE's Fuel Cell Technologies Program Hydrogen Sorption Center of Excellence (HSCoE), UNC conducted Nuclear Magnetic Resonance (NMR) measurements that contributed spectroscopic information as well as quantitative analysis of adsorption processes. While NMR based Langmuir isotherms produce reliable H2 capacity measurements, the most astute contribution to the center is provided by information on dihydrogen adsorption on the scale of nanometers, including the molecular dynamics of hydrogen in micropores, and the diffusion of dihydrogen between macro and micro pores. A new method to assess the pore width using H2 as probe of the pore geometry was developed and is ... continued below

Physical Description

2.2 Mb

Creation Information

Wu, Yue & Kleinhammes, Alfred July 11, 2011.

Context

This text is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. More information about this text can be viewed below.

Who

People and organizations associated with either the creation of this text or its content.

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this text. Follow the links below to find similar items on the Digital Library.

Description

In support of DOE/EERE's Fuel Cell Technologies Program Hydrogen Sorption Center of Excellence (HSCoE), UNC conducted Nuclear Magnetic Resonance (NMR) measurements that contributed spectroscopic information as well as quantitative analysis of adsorption processes. While NMR based Langmuir isotherms produce reliable H2 capacity measurements, the most astute contribution to the center is provided by information on dihydrogen adsorption on the scale of nanometers, including the molecular dynamics of hydrogen in micropores, and the diffusion of dihydrogen between macro and micro pores. A new method to assess the pore width using H2 as probe of the pore geometry was developed and is based on the variation of the observed chemical shift of adsorbed dihydrogen as function of H2 pressure. Adsorbents designed and synthesized by the Center were assessed for their H2 capacity, the binding energy of the adsorption site, their pore structure and their ability to release H2. Feedback to the materials groups was provided to improve the materials’ properties. To enable in situ NMR measurements as a function of H2 pressure and temperature, a unique, specialized NMR system was designed and built. Pressure can be varied between 10-4 and 107 Pa while the temperature can be controlled between 77K and room temperature. In addition to the 1H investigation of the H2 adsorption process, NMR was implemented to measure the atomic content of substituted elements, e.g. boron in boron substituted graphitic material as well as to determine the local environment and symmetry of these substituted nuclei. The primary findings by UNC are the following: • Boron substituted for carbon in graphitic material in the planar BC3 configuration enhances the binding energy for adsorbed hydrogen. • Arrested kinetics of H2 was observed below 130K in the same boron substituted carbon samples that combine enhanced binding energy with micropore structure. • Hydrogen storage material made from activated PEEK is well suited for hydrogen storage due to its controlled microporous structure and large surface area. • A new porosimetry method for evaluating the pore landscape using H2 as a probe was developed. 1H NMR can probe the nanoscale pore structure of synthesized material and can assess the pore dimension over a range covering 1.2 nm to 2.5 nm, the size that is desired for H2 adsorption. • Analysis of 1H NMR spectra in conjunction with the characterization of the bonding structure of the adsorbent by 13C NMR distinguishes between a heterogeneous and homogeneous pore structure as evidenced by the work on AX21 and activated PEEK. • Most of the sorbents studied are suited to hydrogen storage at low temperature (T < 100K). Of the materials investigated, only boron substituted graphite has the potential to work at higher temperatures if the boron content in the favorable planar BC3 configuration that actively contributes to adsorption can be increased.

Physical Description

2.2 Mb

Notes

open for public use

Language

Item Type

Identifier

Unique identifying numbers for this text in the Digital Library or other systems.

  • Report No.: Final Report: Characterization of Hydrogen Adsorption in Carbon-Based Materials by NMR
  • Grant Number: FC36-05GO15081
  • Office of Scientific & Technical Information Report Number: 1018531
  • Archival Resource Key: ark:/67531/metadc837846

Collections

This text is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

What responsibilities do I have when using this text?

When

Dates and time periods associated with this text.

Creation Date

  • July 11, 2011

Added to The UNT Digital Library

  • May 19, 2016, 3:16 p.m.

Usage Statistics

When was this text last used?

Yesterday: 0
Past 30 days: 0
Total Uses: 2

Interact With This Text

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

International Image Interoperability Framework

IIF Logo

We support the IIIF Presentation API

Wu, Yue & Kleinhammes, Alfred. Final Report: Characterization of Hydrogen Adsorption in Carbon-Based Materials by NMR, text, July 11, 2011; United States. (digital.library.unt.edu/ark:/67531/metadc837846/: accessed October 15, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.