Results for “SmOF” | Engineering Papers

DOE OSTI2020

Materials Data on SmOF by Materials Project

SmOF crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Sm3+ is bonded in a body-centered cubic geometry to four equivalent O2- and four equivalent F1- atoms. All Sm–O bond lengths are 2.34 Å. There are three shorter (2.51 Å) and one longer (2.53 Å) Sm–F bond lengths. O2- is bonded to four equivalent Sm3+ atoms to form distorted OSm4 tetrahedra that share corners with six equivalent OSm4 tetrahedra, corners with ten equivalent FSm4 tetrahedra, edges with three equivalent OSm4 tetrahedra, and edges with three equivalent FSm4 tetrahedra. F1- is bonded to four equivalent Sm3+ atoms to form distorted FSm4 tetrahedra that share corners with six equivalent FSm4 tetrahedra, corners with ten equivalent OSm4 tetrahedra, edges with three equivalent OSm4 tetrahedra, and edges with three equivalent FSm4 tetrahedra.

36 MATERIALS SCIENCE↗

DOE OSTI2026

Supramolecular Metal‐Organic Framework Electrocatalysts With Hydration‐Adaptive Gallery Expansion and Linker‐Mediated Distal Ni‐Co Cooperation Enable Framework‐Retentive Oxygen Evolution

Atomic‑level tailoring of electronic communication between spatially separated metal sites offers a route to accelerate multielectron electrocatalysis. We report Ni-TPTC, Co-TPTC, and heterobimetallic Ni-Co-TPTC supramolecular metal-organic frameworks (SMOFs) for the oxygen evolution reaction (OER) built from a terphenyl‑tetracarboxylate (TPTC) linker. Single-crystal X-ray diffraction of heterobimetallic Ni–Co–TPTC reveals trans-bis-aqua octahedral chains assembled into a π-stacked, hydrogen-bonded lattice and confirms retention of the parent architecture, while powder X-ray diffraction supports an isostructural Co analog. In 1.0 M KOH, Ni-Co-TPTC reaches 20 mA cm −2 at 350 mV and maintains operation at ∼60 mA cm −2 for 45 h with modest decay of the initial current. Time‑dependent ex situ diffraction shows dominant framework reflections with low‑angle shifts consistent with gallery dilation (d‑spacing ∼7.7 → ∼9.2 Å) during early operation, while Co K‑edge X‑ray absorption and microscopy reveal Co‑rich oxide/oxyhydroxide‑like domains at longer times that correlate with decay. X‑ray photoelectron spectroscopy, quantified by the Remote Binding‑Energy Differential, tracks composition‑dependent Ni-Co polarization, and DFT free‑energy analysis suggests that a model Ni-Co environment lowers the Co‑centered potential‑limiting step by ∼0.24 eV relative to the Co‑only framework. Furthermore, these results suggest that framework‑retentive expansion and distal Ni-Co coupling can drive OER activity before gradual deligation and oxide formation mark longer‑time degradation.

Supramolecular metal-organic frameworks (SMOFs)↗