ScholarWorks@성균관대학교

초록

Noble metal dichalcogenides (NTMDs), such as PtTe2, provide a platform in which noble metal centers are embedded within chalcogen-coordinated lattices, enabling modulation of the electronic structure of Pt while potentially maximizing noble metal utilization in ultrathin architectures. However, the strong interlayer coupling commonly observed in NTMDs makes the preparation of atomically thin structures challenging, limiting access to their coordination-dependent catalytic properties. In this work, a solvothermal strategy is given for the heteroepitaxial vertical growth of ultrathin PtTe2 nanosheets (NSs) on Te-substituted Cu1.81S nanorods. Surface anion exchange of Cu1.81S nanorods generates metastable Cu6-y Te4 and Cu7Te4 phases with abundant stacking faults, where the Cu6-y Te4 domains act as preferential nucleation sites for PtTe2 epitaxy, leading to vertically aligned NSs with a few-unit-cell thickness. Encouraged by this result, we further attempted the growth of ultrathin PtTe2 NSs on the peripheral facets of Cu1.81S nanoplates to fully exploit the catalytically active Pt sites while suppressing the agglomeration of PtTe2 NSs. Upon thermal treatment, the resulting structures undergo partial phase transformation to PtTe along with the formation of Te vacancies within the PtTe2 lattice, generating PtTe/Te-vacancy-rich PtTe2 heterostructures. The combination of ultrathin morphology, defect engineering, and Pt-Te coordination enables efficient exposure and electronic modulation of Pt active centers, resulting in enhanced oxygen reduction activity with a mass activity of 1.22 A mgPt -1 and excellent durability. Overall, this work demonstrates that lattice-mismatch-driven epitaxial growth provides an effective strategy for constructing ultrathin NTMD architectures and for enhancing noble metal utilization through coordination and defect engineering.

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