Improved hydrogen storage kinetics of nanoconfined NaAlH₄ catalyzed with TiCl₃ nanoparticles

ACS Nano. 2011 May 24;5(5):4056-64. doi: 10.1021/nn200643b. Epub 2011 Apr 5.

Abstract

Nanoparticles of NaAlH(4) have been infiltrated in nanoporous carbon aerogel with TiCl(3) nanoparticles in order to explore possible synergetic effects between nanoconfinement and a functionalized catalytic scaffold. Resorcinol formaldehyde carbon aerogels with an average pore size of 17 nm and total pore volume of 1.26 mL/g were infiltrated with TiCl(3) to obtain an aerogel doped with 3.0 wt % TiCl(3) nanoparticles. NaAlH(4) was melt-infiltrated into the functionalized carbon aerogel at 189 °C and p(H(2)) ∼ 186-199 bar. Energy-dispersive spectrometry (EDS) combined with focused ion beam (FIB) techniques revealed the presence of Na, Al, Ti, and Cl inside the aerogel scaffold material. The infiltrated NaAlH(4) was X-ray amorphous, whereas (27)Al magic-angle spinning (MAS) NMR spectroscopy confirmed the presence of nanoconfined NaAlH(4). Temperature-programmed desorption mass spectroscopy (TPD-MS) and Sieverts' measurements demonstrated significantly improved hydrogen desorption kinetics for this new nanoconfined NaAlH(4)-TiCl(3) material as compared to nanoconfined NaAlH(4) without the catalysts TiCl(3) and to bulk ball-milled samples of NaAlH(4)-TiCl(3). We find that the onset temperature for hydrogen release was close to room temperature (T(onset) = 33 °C), and the hydrogen release rate reached a maximum value at 125 °C, which demonstrates favorable synergetic effects between nanoconfinement and catalyst addition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorption
  • Chlorine / chemistry*
  • Hydrogen / chemistry*
  • Hydrogen / isolation & purification*
  • Kinetics
  • Materials Testing
  • Nanostructures / chemistry*
  • Nanostructures / ultrastructure*
  • Particle Size
  • Titanium / chemistry*

Substances

  • Chlorine
  • Hydrogen
  • Titanium