Solvent-Mediated Reconstruction of the Metal-Organic Framework HKUST-1 (Cu3(BTC)2)

The principle of integral metal-organic framework (MOF) reconstruction is demonstrated for differently degraded HKUST-1 via a facile, one-step, solvent-assisted treatment. Controlled MOF degradation by exposure to 77% humidity, liquid water, and diluted hydrochloric acid produces a mixture of non-porous crystalline hybrid materials containing protonated linker and copper-oxo species, which are then reconstructed back into high-quality HKUST-1 by contacting them with ethanol. X-ray diffraction and sorption kinetics reveal a true memory effect of the system from completely degraded materials. The reconstruction approach is consequently extrapolated to gas-and liquid-phase treatments in a fixed-bed reactor with ethanol and ethanol/water mixtures for use in CO2 capture from a simulated pre-combustion gas stream. Up to a maximum of 94% porosity and 85% CO2 sorption capacity can be recovered from a steamed material. A degradation-reconstruction model is put forward based on X-ray diffraction observations and structural analyses, microscopy, N-2 sorption, thermogravitry-mass spectrometry and IR spectroscopy observations, particularly elucidating the influence of various degradation pathways on the reconstruction.