Interplay of Electronic and Steric Effects to Yield Low‐Temperature CO Oxidation at Metal Single Sites in Defect‐Engineered HKUST‐1
Wang, W. / Sharapa, D.I. / Chandresh, A. / Nefedov, A. / Heißler, S. / Heinke, L. / Studt, F. / Wang, Y. / Wöll, C. (2020)
Angewandte Chemie International Edition, 2020, 59, 26, 10514-10518
- Date: März 2020
In contrast to catalytically active metal single atoms deposited on oxide nanoparticles, the crystalline nature of metal‐organic frameworks (MOFs) allows for a thorough characterization of reaction mechanisms. Using defect‐free HKUST‐1 MOF thin films, we demonstrate that Cu+/Cu2+ dimer defects, created in a controlled fashion by reducing the pristine Cu2+/Cu2+ pairs of the intact framework, account for the high catalytic activity in low‐temperature CO oxidation. Combining advanced IR spectroscopy and density functional theory we propose a new reaction mechanism where the key intermediate is an uncharged O2 species, weakly bound to Cu+/Cu2+. Our results reveal a complex interplay between electronic and steric effects at defect sites in MOFs and provide important guidelines for tailoring and exploiting the catalytic activity of single metal atom sites.