Size‐Dependent Lattice Compression Drives Electronic Modulation of Pt Single‐Atom Sites in Thermally Constructed MOFs

ABSTRACT

Precise regulation of the electronic structure of single‐atom catalysts (SACs) remains challenging because conventional approaches rely on chemical perturbations that often disrupt structural uniformity and provide limited tunability. Here, we report a physical strategy for continuous, size‐dependent electronic modulation of Pt single atoms using lateral dimension as an experimentally accessible structural descriptor. Pt single atoms were pre‐coordinated in Pt–TCPP units and assembled with Co ²⁺ into two‐dimensional Co@Pt‐SAC nanosheets. Temperature‐programmed cooling enabled precise control of nanosheet lateral size while preserving the primary Pt─N coordination environment. Decreasing nanosheet size induced progressive lattice compression, evidenced by the shift of the apparent Pt─N scattering feature in FT‐EXAFS spectra from 1.64 to 1.57 Å. Meanwhile, the local electrostatic potential at Pt sites increased from −16.880 to −14.872 kcal mol ⁻¹ , indicating pronounced Pt‐centered electronic modulation. This modulation strengthened the interaction between Pt sites and triiodide species, accelerating interfacial charge transfer during the I ₃ ⁻ /I ⁻ redox process. These findings establish a direct correlation between lateral size‐dependent lattice evolution and the electronic structure of single‐atom active sites, offering a general physical route for continuous electronic tuning of SACs without altering their primary coordination chemistry.