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Aminopolymer functionalization with fluoroalkyl chains and resulting void volume afford 4.1-fold increase in amine efficiency and 2.8-fold increase in CO 2 capture capacity in the fluorinated material.
A remarkably stable FLP-CO 2 adduct smoothly reacts with Tf 2 O to undergo C–O bond cleavage with the formation of the formal FLP adduct of the elusive dication C 2 O 3 2+ .
H x RuO 2 acts as a standalone catalyst exhibiting selective hydrogenation under mild conditions. Mobile protons embedded in the oxide lattice play an important role in stabilizing the distorted structure, and facile proton dynamics is key to improving catalytic properties.
Recent developments in CO 2 capture using porous organic polymers (POPs) have received accrescent attention due to their sorbent properties such as high CO 2 uptake capacity and selectivity, tunable chemical structure and permanent porosity. POPs are constructed using two and/or three-dimensional organic monomers (building blocks) linked to each other through covalent bonding, creating high porosity. The pore structure in POPs is exceptionally stable, which leads to their cyclable CO 2 adsorption performance. However, POPs generally suffer from low CO 2 uptake and selectivity due to their interaction with CO 2 in physisorption limits (20–40 kJ mol -1 ). Similar to that in other physisorbents, the CO 2 uptake capacity of POPs further decreases under humid conditions. Pursuant to these limitations, amine functionalization in POPs has resulted in enhanced CO 2 uptake performance with improved CO 2 selectivity over non-polar gases such as N 2 . More importantly, several types of amine-functionalized POPs showed that the CO 2 uptake could remain intact under humid conditions such as in post-combustion flue gas. This review article covers recent developments in amine-functionalized porous organic polymers. Three main categories of amine functionalization, such as direct amine synthesis, amine impregnation and amine grafting, were investigated in detail by considering the effect of amines on the sorbent properties and CO 2 capture performance of POPs. The recent findings in amine-functionalized POPs were investigated including porous polymeric networks (PPNs), covalent organic frameworks (COFs), amine linked POPs, hyper-crosslinked polymers (HCPs), conjugated microporous polymers (CMPs), benzimidazole linked polymers (BILPs), porous aromatic frameworks (PAFs) and polymers of intrinsic microporosity (PIMs).
We have developed a specialized microfluidic electrochemical cell that enables in situ investigation of the electrochemical corrosion of microgram quantities of redox active solids. The advantage of downscaling is the reduction of hazards, waste, expense, and greatly expanding data collection for hazardous materials, including radioactive samples. Cyclic voltammetry was used to monitor the oxidation–reduction cycle of minute quantities of micron-size uraninite (UO 2 ) particles, from the formation of hexavalent uranium (U(VI)), U 3 O 7 and reduction to UO 2+x . Reaction progress was also studied in situ with scanning electron microscopy. The electrochemical measurements matched those obtained at the bulk-scale and were consistent with ex situ characterization of the run products by X-ray photoelectron spectroscopy, scanning transmission electron microscopy, and atomic force microscopy; thus, demonstrating the utility of the microfluidic approach for studying radioactive materials.
Diamine-appended metal–organic frameworks can be optimized as adsorbents for pressure-swing purification of crude natural gas. A cooperative CO 2 binding mechanism enables high CO 2 swing capacities and enhanced performance under humid conditions.
The reaction rates of lanthanide and actinide cations with CO 2 are dictated by the crossing between the potential energy surface (PES) evolving from the ground state reactants (red) and the PES leading to the ground state products (green).
Microalgae could be sustainably used to sequester CO 2 and processed to fuels and chemicals.
The activity of co-electrocatalytic CO 2 reduction can be optimized when the redox mediator and metal complex are modified to minimize the difference in their reduction potentials.
Cobalt-doped forsterite carbonates to cobalt-rich magnesite in thin water films, but its carbonation rate is slower than that of pure forsterite.
Electrochemical reactors based on gas diffusion electrodes (GDE) enable high current densities for reactions such as CO 2 reduction. AutoGDE is a platform for automating GDE experiments to accelerate catalyst discovery and reaction engineering.
The minireview highlights recent developments in designing electrocatalysts for the co-reduction of CO 2 and nitrates into urea. It also discusses advanced detection methods for intermediates and final products, as well as future research prospects.
Carboxylating lignin and lignite fillers to sequester CO 2 in composite materials.
Doping transition metals in Cu 13 clusters enhance CO 2 reduction by altering electronic and magnetic properties, lowering overpotentials by ∼20%.
The functionalisation of organic linkers in metal–organic frameworks (MOFs) to improve gas uptake is well-documented. Although the positive role of free carboxylic acid sites in MOFs for binding gas molecules has been proposed in computational studies, relatively little experimental evidence has been reported in support of this. Primarily this is because of the inherent synthetic difficulty to prepare MOF materials bearing free, accessible –COOH moieties which would normally bind to metal ions within the framework structure. Here, we describe the direct binding of CO 2 and C 2 H 2 molecules to the free –COOH sites within the pores of MFM-303(Al). MFM-303(Al) exhibits highly selective adsorption of CO 2 and C 2 H 2 with a high selectivity for C 2 H 2 over C 2 H 4 . In situ synchrotron X-ray diffraction and inelastic neutron scattering, coupled with modelling, highlight the cooperative interactions of adsorbed CO 2 and C 2 H 2 molecules with free –COOH and –OH sites within MFM-303(Al), thus rationalising the observed high selectivity for gas separation.
A novel 4,8-c scu -type aluminum-based metal–organic framework shows a robust structure, reversible SO 2 adsorption with high capacity, and high SO 2 /N 2 , SO 2 /CO 2 , and SO 2 /CH 4 selectivities.
Metal–organic frameworks (MOFs) exhibit significant potential for mitigating carbon emissions due to their high porosity and tunability. Despite numerous reports on CO 2 capture by MOF sorbents, a common challenge is their poor selectivity for CO 2 over water. Moreover, in-depth studies are much needed to elucidate the relationships among the pore surface structure, hydrophobicity, and CO 2 uptake capacity/selectivity. In this work, we investigate the factors influencing CO 2 adsorption capacity and selectivity under humidity in a series of isoreticular pillar-layer structures, Ni 2 (L) 2 (dabco) (L = bdc, ndc, adc). Our study shows that increasing ligand conjugation not only results in increased hydrophobicity, decreased pore size and BET surface area, but also leads to the change of primary binding sites of water molecules and higher binding energy of CO 2 , all of which contribute to largely increased CO 2 uptake capacity under humid conditions. Additionally, increasing ligand conjugation and consequently hydrophobicity slow down and reduce competitive water adsorption drastically. Notably, the MOF made of ligand with the highest conjugation, Ni 2 (adc) 2 (dabco), exhibits significantly enhanced CO 2 adsorption in N 2 /CO 2 binary mixtures under relatively high humidity (50% RH), with an increase of ~31% and ~36% for the composition of 15/85 and 50/50, respectively, compared to dry conditions. An experimental FTIR study and DFT theoretical calculations confirm that H 2 O occupies different primary binding site in Ni 2 (bdc) 2 (dabco) and Ni 2 (adc) 2 (dabco), and under humid conditions a higher binding energy of CO 2 is achieved with preferential H 2 O/CO 2 co-adsorption in Ni 2 (adc) 2 (dabco), potentially creating additional adsorption sites for CO 2 .
In situ X-ray characterization and DFT calculations reveal that Ni configuration and N-coordination modulate the binding energies of *COOH and *H intermediates, with their difference being key to predicting CO 2 RR activity on Ni single atomic sites.