CO2 capture enhancement for InOF-1: confinement of 2-propanol.

The 2-propanol (i-PrOH) adsorption properties of InOF-1 are investigated along with the confinement of small amounts of this alcohol to enhance the CO2 capture for i-PrOH@InOF-1 (1.25-fold improvement compared to pristine InOF-1). InOF-1 exhibited a high affinity towards i-PrOH, experimentally quantified by ΔHads (-55 kJ mol-1), and DFT geometry optimisations showed strong hydrogen bonding between O(i-PrOH) and H(µ2-OH). Quantum chemical models demonstrated that the CO2 capture increase for i-PrOH@InOF-1 was due to a decrease in the void surface of InOF-1 (bottleneck effect), and the formation of essential hydrogen bonds of CO2 with i-PrOH and with the hydroxo functional group (µ2-OH) of InOF-1.

Outstanding reversible H2S capture by an Al(iii)-based MOF.

The MOF-type MIL-53(Al)-TDC was demonstrated to be an optimal adsorbent for H2S capture combining an unprecedented uptake at room temperature, excellent cyclability and low-temperature regeneration.

Humidity-induced CO2 capture enhancement in Mg-CUK-1.

Kinetic CO2 adsorption measurements in the water-stable and permanently microporous Metal-organic framework material, Mg-CUK-1, reveal a 1.8-fold increase in CO2 capture from 4.6 wt% to 8.5 wt% in the presence of 18% relative humidity. Thermodynamic CO2 uptake experiments corroborate this enhancement effect, while grand canonical Monte Carlo simulations also support the phenomenon of a humidity-induced increase in the CO2 sorption capacity in Mg-CUK-1. Molecular simulations were implemented to gain insight into the microscopic adsorption mechanism responsible for the observed CO2 sorption enhancement. These simulations indicate that the cause of increasing CO2 adsorption enthalpy in the presence of H2O is due to favorable intermolecular interactions between the co-adsorbates confined within the micropores of Mg-CUK-1.

Confinement of H2O and EtOH to enhance CO2 capture in MIL-53(Al)-TDC.

EtOH sorption properties were investigated in MIL-53(Al)-TDC and found a strong interaction between EtOH and the MOF material (ΔHads = 69.6 kJ mol-1). CO2 capture was enhanced upon confining small amounts of H2O. Upon confining small amounts of EtOH however, the CO2 uptake was not improved. The difference in CO2 uptake with EtOH and H2O was rationalised using computational calculations. The analysis of the quantum theory of atoms in molecules (QTAIM) showed a covalent interaction between a MOF model and confined molecules (EtOH and H2O), and no difference in the hydrogen bonds between confined molecules and CO2.

Greener synthesis of Cu-MOF-74 and its catalytic use for the generation of vanillin.

A greener synthesis of Cu-MOF-74 was obtained, for the first time, in methanol as the unique solvent and at room temperature. Full characterisation of the MOF material showed its purity and also its nanocrystalline nature. Complete activation (150 °C for 1 h and 10-3 bar) of Cu-MOF-74 afforded unsaturated Cu metal sites and this was corroborated by in situ DRIFT spectroscopy. The access to these Cu open metal sites was tested for the catalytic transformation of trans-ferulic acid to vanillin (yield of 71% and 97% selectivity) and a plausible catalytic reaction mechanism was postulated based on quantum chemical calculations.