The capture of CO 2 from flue gases derived from fossil-fueled power plants and the absorption of CO 2 /H 2 S for natural gas sweetening purposes are two relevant industrial problems closely related to very important environmental, economical, and technological problems that need to be solved. Amine-based technologies are widely used in the industry for these purposes, but they lead to several problems that have led many researchers to pose new alternatives. Ionic liquids (ILs) have emerged in the last few years as promising new acid gas absorbents, and thus, this remarkable interest, in both industry and academia, has led to a large collection of experimental and theoretical studies in which the most important aspects of the absorption process are analyzed. In this review, we show the most relevant conclusions obtained from the analysis of the literature, analyzing the state-of-the-art results, trying to infer the viability of ILs as an alternative to the available amine-based absorption processes, and showing the possible future directions of research.

The large collection of thermophysical properties data for liquids available in the open literature is analyzed, describing its importance for industrial purposes. Although there has been a boom of thermophysical properties measurements for these fluids in the past decade, the reported analysis shows that studies have been centered on a limited number of fluids, whereas data collection for the new family ionic liquids is lacking. Measurements have been performed for limited temperature ranges, and pressure effects on the properties are extremely scarce in the literature; remarkable differences among data from different literature sources are reported. The need of sample purity quantification is analyzed together with the strong effect of these impurities on thermophysical properties. Available predictive models for the studied properties are analyzed together with the quality of their predictions. The main conclusion of this review is to point out the need of further systematic thermophysical studies, including for new environmentally friendly ionic liquids, carried out with interlaboratory comparisons, which allow the development of reference data sets.

Efficient CO 2 scrubbing without a significant energy penalty remains an outstanding challenge for the fossil fuel-burning industry where aqueous amine solutions are still widely used. Porous materials have long been evaluated for next generation CO 2 adsorbents. Porous polymers, robust and inexpensive, show promise as feasible materials for the capture of CO 2 from warm exhaust fumes. We report the syntheses of porous covalent organic polymers (COPs) with CO 2 adsorption capacities of up to 5616 mg g À1 (measured at high pressures, i.e. 200 bar) and industrially relevant temperatures (as warm as 65 C). COPs are stable in boiling water for at least one week and near infinite CO 2 /H 2 selectivity is observed.

Although several Prussian Blue analogues (PBAs) have been investigated as water oxidation catalysts, the field lacks a comprehensive study that focuses on the design of the ideal PBA for this purpose. Here, members of a series of PBAs with different cyanide precursors have been investigated to study the effect of hexacyanometal groups on their electrocatalytic water oxidation activities. Cyclic voltammetric, chronoamperometric, and chronopotentiometric measurements have revealed a close relationship between the electron density of electroactive cobalt sites and electrocatalytic activity, which has also been confirmed by infrared and XPS studies. Furthermore, pH-dependent cyclic voltammetry and computational studies have been performed to gain insight into the catalytic mechanism and electronic structure of cyanide-based systems to identify possible intermediates and to assign the rate-determining step of the target process.

Carbon dioxide capture and separation requires robust solids that can stand harsh environments where a hot mixture of gases is often found. Herein, the fi rst and comprehensive syntheses of porous sulfur-bridged covalent organic polymers (COPs) and their application for carbon dioxide capture in warm conditions and a wide range of pressures (0-200 bar) are reported. These COPs can store up to 3294 mg g − 1 of carbon dioxide at 318 K and 200 bar while being highly stable against heating up to 400 ° C. The carbon dioxide capacity of the COPs is also not hindered upon boiling in water for at least one week. Physisorptive binding is prevalent with isosteric heat of adsorptions around 24 kJ mol − 1 . M06-2X and RIMP2 calculations yield the same relative trend of binding energies, where, interestingly, the dimer of triazine and benzene play a cooperative role for a stronger binding of CO 2 (19.2 kJ mol − 1 ) as compared to a separate binding with triazine (13.3 kJ mol − 1 ) or benzene (11.8 kJ mol − 1 ).

Co/Fe Prussian Blue coordination networks have recently been investigated for heterogeneous water oxidation catalysis. Despite their robustness and stability in both acidic and neutral media, the relatively low current density obtained is their main drawback as a result of their low surface concentration. A novel synthetic approach was employed using a pentacyanometalate-based metallopolymer for the preparation of amorphous Co/Fe coordination polymers to overcome this problem. The surface concentration was improved approximately 7-fold, which also resulted in an increase in the catalytic activity. A current density of 1 mA·cm(-2) was obtained only at η = 510 mV, while the same current density could be obtained at higher overpotentials (>600 mV) with conventional Prussian Blue analogues. IR, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy studies were performed to investigate the stability of electrodes before and after the electrocatalytic process. The results of this study indicate that the rich and diverse chemistry of pentacyanometalates makes them potential candidates for application in heterogeneous water oxidation catalysis.

A series of structurally related pseudocubic metal cyanide clusters of Re(II) and 3d metal ions [{MX}4{Re(triphos)(CN)3}4] (M = Mn, Fe, Co, Ni, Zn; X = Cl, I, -OCH3) have been prepared, and their magnetic and electrochemical properties have been probed to evaluate the effect of changing the identity of the 3d metal ion. Electrochemistry of the clusters reveals several rhenium-based oxidation and reduction processes, some of which result in cluster fragmentation. The richest electrochemistry was observed for the iron congener, which exists as the Re(I)/Fe(III) cluster at the resting potential and exhibits six clear one-electron reversible redox couples and two, closely spaced one-electron quasi-reversible processes. The [{MnIICl}4{ReII(triphos)(CN)3}4] complex exhibits single molecule magnetism with a fast tunneling relaxation process observed at H = 0 determined by micro-SQUID magnetization measurements. A comparative evaluation of the magnetic properties across the series reveals that the compounds exhibit antiferromagnetic coupling between the metal ions, except for [{NiIICl}4{ReII(triphos)(CN)3}4] that shows ferromagnetic behavior. Despite the large ground-state spin value of [{NiIICl}4{ReII(triphos)(CN)3}4] (S = 6), only manganese congeners exhibit SMM behavior to 1.8 K.

The Si2p binding and the Si KLL kinetic energy difference between the SiO 2 layer and Si substrate is shown to be influenced by application of external voltage bias to the sample holder due to the differential charging as was already reported earlier (Ulgut, B.; Suzer, S. J. Phys. Chem. B 2003, 107, 2939). The cause of this bias induced (physical)-shift is now proven to be mostly due to partial neutralization by the stray electrons within the vacuum system by (i) introducing additional stray electrons via a filament and following their influence on the measured binding energy as a function of the applied voltage, (ii) measuring the Auger parameter. It is also shown that citrate-capped gold nanoclusters deposited on the SiO 2 /Si system experience differential charging similar to that of the oxide layer rather than the silicon substrate.