title: Growth and Tunable Surface Wettability of Vertical MoS2 Layers for Improved Hydrogen Evolution Reactions.
abstract: Layered materials, especially the transition metal dichalcogenides (TMDs), are of interest for a broad range of applications. Among the class of TMDs, molybdenum disulfide (MoS2) is perhaps the most studied because of its natural abundance and use in optoelectronics, energy storage and energy conversion applications. Understanding the fundamental structure-property relations is key for tailoring the enhancement in the above-mentioned applications. Here, we report a controlled powder vaporization synthesis of MoS2 flower-like structures consisting of vertically grown layers of MoS2 exhibiting exposed edges. This growth is readily achievable on multiple substrates, such as graphite, silicon, and silicon dioxide. The resulting MoS2 flowers are highly crystalline and stoichiometric. Further observations using contact angle indicate that MoS2 flowers exhibit the highest reported contact angle of ∼160 ± 10°, making the material super hydrophobic. This surface wettability was further tuned by changing the edge chemistry of the MoS2 flowers using an ozone etching treatment. Hydrogen evolution reaction (HER) measurements indicate that the surface treated with UV-ozone showed a reduction in the Tafel slope from 185 to 54 mV/dec, suggesting an increase in the amount of reactive surface to generate hydrogen.
authors: The Department of Material Science and Engineering, Center for 2-Dimensional Layered Materials, and NSF I/UCRC Center for Atomically Thin Multifunctional Coatings, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors: Ganesh R
authors: GR
authors: Bhimanapati
authors: The Department of Material Science and Engineering, Center for 2-Dimensional Layered Materials, and NSF I/UCRC Center for Atomically Thin Multifunctional Coatings, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors: Trevor
authors: T
authors: Hankins
authors: The Department of Material Science and Engineering, Center for 2-Dimensional Layered Materials, and NSF I/UCRC Center for Atomically Thin Multifunctional Coatings, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors: Yu
authors: Y
authors: Lei
authors: The Department of Material Science and Engineering, Center for 2-Dimensional Layered Materials, and NSF I/UCRC Center for Atomically Thin Multifunctional Coatings, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors: Rafael A
authors: RA
authors: Vilá
authors: Angstron Materials, Inc. ,1240 McCook Avenur, Dayton, Ohio 45404, United States.
authors: Ian
authors: I
authors: Fuller
authors: The Department of Material Science and Engineering, Center for 2-Dimensional Layered Materials, and NSF I/UCRC Center for Atomically Thin Multifunctional Coatings, Pennsylvania State University , University Park, Pennsylvania 16802, United States.|Department of Physics and Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors: Mauricio
authors: M
authors: Terrones
authors: The Department of Material Science and Engineering, Center for 2-Dimensional Layered Materials, and NSF I/UCRC Center for Atomically Thin Multifunctional Coatings, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors: Joshua A
authors: JA
authors: Robinson
keywords: HERs; MoS2; contact angle; nano flowers; transition metal dichalcogenides