Flashcard library · Chemistry · PaperFren
Defect hydroxides in UiO-66 shuttle protons
Simulations of missing-linker UiO-66 put charge-balancing OH on under-coordinated Zr and show those sites swap between hydroxide and water by rapid proton transfer with extra-framework water.
Keep what you just learned
Save these 11 cards to your NoteFren library. Your first review starts right away, and each card links back to the study it came from.
What two open questions about UiO-66 missing linkers did the paper target?
The charge-balancing species after BDC2− loss, and the defect structure itself.
Source: Dynamic acidity in defective UiO-66 · DOI · quote verified
Where do charge-balancing hydroxides sit?
Bonded to under-coordinated Zr sites, creating potential acid centres.
Source: Dynamic acidity in defective UiO-66 · DOI · quote verified
What dynamic process involves those hydroxides and water?
Rapid proton transfer so Zr ligands alternate between OH− and H2O.
Source: Dynamic acidity in defective UiO-66 · DOI · quote verified
What mean Zr⋯O distance did 300 K AIMD give?
2.23 Å, matching Trickett’s 2.24(3) Å at 300 K.
Source: Dynamic acidity in defective UiO-66 · DOI · quote verified
How large is the direct O0–O1 proton-transfer barrier?
Only 6.5 kJ mol−1, 21.0 lower than the two-step O3-mediated path.
Source: Dynamic acidity in defective UiO-66 · DOI · quote verified
How much more strongly does NH3 bind at the defect?
110.1 versus 75.8 kJ mol−1 in the perfect region.
Source: Dynamic acidity in defective UiO-66 · DOI · quote verified
What double-transfer rate is seen at 300 K with water at O3?
About one event per 15 ps.
Source: Dynamic acidity in defective UiO-66 · DOI · quote verified
Does proton transfer appear at 100 K in 10 ps?
No—as expected from the 10–15 ps interval at 300 K.
Source: Dynamic acidity in defective UiO-66 · DOI · quote verified
What happens to water at 700 K?
It desorbs into the pore, leaving Zr–OH and a bare Zr site.
Source: Dynamic acidity in defective UiO-66 · DOI · quote verified
How long were 300 K AIMD production runs?
30 ps (60 000 steps, 0.5 fs timestep).
Source: Dynamic acidity in defective UiO-66 · DOI · quote verified
Water binding at Zr1 versus O3 in D0?
161.5 versus 86.9 kJ mol−1 per water.
Source: Dynamic acidity in defective UiO-66 · DOI · quote verified