Enhanced catalytic activity in strained chemically exfoliated WS2 nanosheets for hydrogen evolution
Damien Voiry, Hisato Yamaguchi, Junwen Li, Rafael Silva, Diego C.
B. Alves, Takeshi Fujita, Mingwei Chen, Tewodros Asefa, Vivek B.
Shenoy, Goki Eda, and Manish Chhowalla
Nature Materials 12, 850 (2013)
evolution of hydrogen through electrocatalysis at low overpotentials
holds tremendous promise for clean energy. Hydrogen evolution can be
easily achieved by electrolysis at large potentials that can be lowered
with expensive platinum-based catalysts. Replacement of Pt with
inexpensive, earth-abundant electrocatalysts would be significantly
beneficial for clean and efficient hydrogen evolution. To this end,
promising results have been reported using 2H (trigonal prismatic) XS2 (where X = Mo or W) nanoparticles with a high concentration of metallic edges. The key challenges for XS2
are increasing the number and catalytic activity of active sites. Here
we report monolayered nanosheets of chemically exfoliated WS2
as efficient catalysts for hydrogen evolution with very low
overpotentials. Analyses indicate that the enhanced electrocatalytic
activity of WS2 is associated with the high concentration of
the strained metallic 1T (octahedral) phase in the as-exfoliated
nanosheets. Our results suggest that chemically exfoliated WS2 nanosheets are interesting catalysts for hydrogen evolution.