Fig. 5: Structure-sensitive conversion of formaldehyde (FA) over defect-engineered ZIF-8.
From: Structure sensitivity in gas sorption and conversion on metal-organic frameworks
a Contour plot of the crystal surface-averaged in situ infrared spectra of a defective ZIF-8 crystal, showing the formation of formate, di-/poly-oxymethylene (DOM/POM), and methoxy surface species (relevant bands indicated by dashed lines in the contour plot). b A plot showing plane-dependent response pressures for intermediate surface species, thus showing structure-sensitive FA conversion, as intermediates are observed at lower pressures on high-index planes (note: pyrrole-induced changes in crystal facet size ratios prevented the analysis of the {111} facets). Based on the observed species and in accordance with the literature32,48, we propose two possible mechanisms for FA conversion over defective ZIF-8: a methoxy-mediated (c) and formate-mediated (d) mechanism.
