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.

Nanostructured hydrotreating catalysts for electrochemical hydrogen evolution

“…In the time being, it is important to note that the Mo-edge sites that are active for HDS have been proposed as the active sites for HER by MoS 2 . [30][31][32] Two perspectives by our group and the group of Chorkendorff have summarized the chronological development of this area until the end of 2011. 9,10 Briefly, initial studies were done by Tribusch et al in 1970s on the electrochemistry and photochemistry of MoS 2 layered crystals, 33 but it was not until Nørskov, Chorkendorff, and co-workers showed in 2005 that the edge sites of MoS 2 have a good HER activity that interest in this type of materials as HER catalysts spurred.…”

One‐Dimensional Earth‐Abundant Nanomaterials for Water‐Splitting Electrocatalysts

“…The effect of different morphologies on their catalytic activities has also been studied for a variety of earth‐abundant HER electrocatalysts, such as MoS 2 ,41, 42, 43 amorphous MoS 2 ,44 WS 2 ,45, 46 Ni 2 P,47 CoP48 and Ni‐Mo alloys 49, 50. In 2014, Jin and coworkers reported the synthesis of metallic cobalt pyrite (cobalt disulfide, CoS 2 ) with different morphologies including films, microwires and nanowires, and showed their capabilities as a high‐activity candidate for HER 27.…”

Face the Edges: Catalytic Active Sites of Nanomaterials

“…More researches need to be done in designing new structures utilizing the convenience of edge properties and searching new catalytic reactions. Other transition metal dichalogenides (TMD) also experimentally showed promising activities for HER 60, 61. Meanwhile theoretical study suggests the edge sites of MoSe 2 and WSe 2 should be comparable or even better performance than MoS 2 for HER 62.…”