title: Enhanced catalytic activity in strained chemically exfoliated WS₂ nanosheets for hydrogen evolution.
abstract: Efficient 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.
authors.affiliation: Rutgers University, Materials Science and Engineering, 607 Taylor Road, Piscataway, New Jersey 08854, USA.
authors.forename: Damien
authors.initials: D
authors.lastname: Voiry
authors.forename: Hisato
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Junwen
authors.initials: J
authors.lastname: Li
authors.forename: Rafael
authors.initials: R
authors.lastname: Silva
authors.forename: Diego C B
authors.initials: DC
authors.lastname: Alves
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujita
authors.forename: Mingwei
authors.initials: M
authors.lastname: Chen
authors.forename: Tewodros
authors.initials: T
authors.lastname: Asefa
authors.forename: Vivek B
authors.initials: VB
authors.lastname: Shenoy
authors.forename: Goki
authors.initials: G
authors.lastname: Eda
authors.forename: Manish
authors.initials: M
authors.lastname: Chhowalla
mesh_terms: D002384:Catalysis; D055664:Electrochemical Techniques; D006859:Hydrogen / Q000737:chemistry*; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry*; D017973:Tungsten Compounds / Q000737:chemistry*
chemical_list: D017973:Tungsten Compounds; D006859:Hydrogen