Phase-Transition Mo1–xVxSe2 Alloy Nanosheets with Rich V–Se Vacancies and Their Enhanced Catalytic Performance of Hydrogen Evolution Reaction
| Autor: | In Hye Kwak, Hong Seok Kang, Ju Yeon Kim, Ik Seon Kwon, Jin-Gyu Kim, Tekalign Terfa Debela, Jeunghee Park, Seung Jo Yoo |
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| Rok vydání: | 2021 |
| Předmět: |
Phase transition
Materials science Alloy General Engineering General Physics and Astronomy engineering.material Gibbs free energy Catalysis Metal symbols.namesake Crystallography Vacancy defect Phase (matter) visual_art symbols engineering visual_art.visual_art_medium General Materials Science Density functional theory |
| Zdroj: | ACS Nano. 15:14672-14682 |
| ISSN: | 1936-086X 1936-0851 |
| Popis: | Alloys of transition-metal dichalcogenide can display distinctive phase evolution because of their two-dimensional structures. Herein, we report the colloidal synthesis of Mo1-xVxSe2 alloy nanosheets with full composition tuning. Alloying led to a phase transition at x = 0.7 from the semiconducting 2H phase MoSe2 to the metallic 1T phase VSe2. It also produced significant V and Se vacancies, which became the richest in the 2H phase at x = 0.3-0.5. Extensive spin-polarized density functional theory calculations consistently predicted the 2H-1T phase transition at x = 0.7, in agreement with the experimental results. The vacancy formation energy also supports the formation of V and Se vacancies. Alloying in the 2H phase enhanced the electrocatalytic performance toward hydrogen evolution reaction (HER) at x = 0.3 (in 0.5 M H2SO4) or 0.4 (in 1 M KOH). The Gibbs free energy along the HER pathway indicates that this maximum performance is due to the highest concentration of active V and Se vacancy sites. |
| Databáze: | OpenAIRE |
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