Abstract
The ability to control the active edge sites of transition metal dichalcogenides (TMDs) is crucial for modulating their chemical activity for various electrochemical applications, including hydrogen evolution reactions. In this study, we demonstrate a colloidal synthetic method to prepare core-shell-like heterostructures composed of MoSe2 and WSe2 via a two-step sequential growth. By overgrowing WSe2 on the surface of preexisting MoSe2 nanosheet edges, MoSe2-core/WSe2-shell heterostructures were successfully obtained. Systematic comparisons of the secondary growth time and sequential order of growth suggest that the low synthetic temperature conditions allow the stable overgrowth of shells rich in WSe2 on top of the core of MoSe2 with low Gibbs formation energy. The electrochemical analysis confirms that the catalytic activity correlates to the core-shell composition variation. Our results propose a new strategy to control the edge site activity of TMD materials prepared by colloidal synthesis, which is applicable to diverse electrochemical applications.
Highlights
Transition metal dichalcogenides (TMDs) have attracted tremendous attention owing to their interesting properties originating from their two-dimensional (2D) structures, which generally consist of a central transition metal layer sandwiched between chalcogen atomic layers
MoSe2 and WSe2 nanosheets were grown using a colloidal hot-injection method. 108 mg (0.4 mmol) of Mo(CO)6 or 141 mg (0.4 mmol) of W(CO)6 were added into a 100 mL three-neck flask which was pre-loaded with 78.5 mg (0.28 mmol) of TDPA dissolved into 6 g of OA. 250 mg Ph2Se2, the selenium precursor, was dissolved in 4 g of OA in a separate vial
We presented core-shell heterostructures of MoSe2/WSe2 TMDs obtained via a twostep colloidal synthesis
Summary
Transition metal dichalcogenides (TMDs) have attracted tremendous attention owing to their interesting properties originating from their two-dimensional (2D) structures, which generally consist of a central transition metal layer sandwiched between chalcogen atomic layers. A diverse selection of constituents (metals and chalcogens), crystal phases (e.g., trigonal prismatic and octahedral), and a number of layers impart characteristic physical properties, depending on the TMD structures. The phase transition between metallic 1T and semiconducting 2H-phases occurs via chemical intercalation [3,4] or laser excitation [5], without changing the TMD layer constituents. The optical bandgap of semiconducting TMD layers exhibits a direct-to-indirect transition depending on the number of layers. The dangling bond-free van der Waals (vdW) interactions, together with the analogous crystal structures, allow the preparation of TMD heterostructures with diverse compositions and geometries. Numerous preparation techniques, including mechanical exfoliation or physical/chemical vapor deposition, have been employed to prepare TMD-based heterostructures [10,11,12,13]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
