Enhancing MWNT Hydrogen Storage via V/Pd Decoration

"Enhancement of hydrogen storage capacity of carbon nanotubesvia spill-over from vanadium and palladium nanoparticles"

Zacharia, R.; Kim, K. Y.; Kibria, A. K. M. F.; Nahm, K. S. Chem. Phys. Lett. 2005, 412, 369-375.
doi:10.1016/j.cplett.2005.07.020

"The increased hydrogen storage capacity of transition metal-doped carbon nanostructures is attributed to the initial hydrogen adsorption by metal nanoparticles which subsequently dissociate the hydrogen molecules and spill them over to carbon nanotubes."

Materials: V-MWNT; Pd-MWNT

Synthesis:
Electroless:
100 mg MWNTs (CVD from acetylene, purified) and 3 mg PdCl2 were sonicated in acetone for 12 h. Pd2+/Pd: +0.951V (vs SHE).
Reduction-H2:
100 mg MWNTs and 5 mg VCl3 were sonicated for 12 h. Reduced by hydrogen at 250C for 2h.

Characterization:
TEM (Likely incorrect assignments)
Raman
Hydrogen adsorption:

• Sieverts volumetric apparatus: 100 mg CNT; 6h 400C 10(-4) degassing; 2MPa H2.



• V-MWNT (0.69wt%) = Pd-MWNT (0.66) > purified MWNT (0.53) > as-produced (0.31)



• More than half of the hydrogen adsorbed might be attributed to carbon phase



• Desorption: more reversible for V-MWNT than Pd-MWNT at r.t.

Applications:
Hydrogen Storage