posted on 2013-12-11, 00:00authored byDamien Voiry, Maryam Salehi, Rafael Silva, Takeshi Fujita, Mingwei Chen, Tewodros Asefa, Vivek
B. Shenoy, Goki Eda, Manish Chhowalla
We
report chemically exfoliated MoS2 nanosheets with
a very high concentration of metallic 1T phase using a solvent free
intercalation method. After removing the excess of negative charges
from the surface of the nanosheets, highly conducting 1T phase MoS2 nanosheets exhibit excellent catalytic activity toward the
evolution of hydrogen with a notably low Tafel slope of 40 mV/dec.
By partially oxidizing MoS2, we found that the activity
of 2H MoS2 is significantly reduced after oxidation, consistent
with edge oxidation. On the other hand, 1T MoS2 remains
unaffected after oxidation, suggesting that edges of the nanosheets
are not the main active sites. The importance of electrical conductivity
of the two phases on the hydrogen evolution reaction activity has
been further confirmed by using carbon nanotubes to increase the conductivity
of 2H MoS2.