Within the most mesmerizing materials in the world of optoelectronics, mixed halide perovskites (MHP) have been distinguished due to the tunability of their optoelectronic properties, balancing both the light harvesting efficiency and charge extraction into highly efficient solar devices. This feature has drawn the attention of analogous hot-topics as photocatalysis for carrying out more efficiently the degradation of organic compounds. However, the photo-oxidation ability of perovskite does not only depend on its excellent light-harvesting properties, but also on the surface chemical environment provided during its synthesis. Accordingly, we studied the role of surface chemical states of MHP based nanocrystals (NCs) synthesized by hot-injection (H-I) and anion-exchange (A-E) approaches, on their photocatalytic (PC) activity for the oxidation of β-naphthol as a model system. We concluded that iodide vacancies are the main surface chemical states that facilitate the formation of superoxide ions, O 2 •─ , responsible for the PC activity in A-E-MHP. Conversely, the PC performance of H-I-MHP is related to the appropriate balance between band gap and a highly oxidizing valence band. This work offers new insights on the surface properties of MHP related to their catalytic activity in photochemical applications.

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Mean activity coefficient values for NaCl in the mixture (water + ionic liquid) (IL) as solvent (IL being 1-ethyl-3-methyl-imidazolium methanesulfonate, [Emim][MeSO 3 ] or 1-ethyl-3-methyl-imidazolium ethyl sulfate, [Emim][EtSO 4 ]) were determined from the electrode potential measurements of the cell: Na−(ISE) | NaCl (m A ), ILs (w), H 2 O (1 − w) | Cl−(ISE) (ISE means ion selective electrode) at total ionic strengths ranging from 0.10 to 3.20 mol•kg −1 and at 298.15 K. Different weight fractions (w) of ILs (w = 0.01, 0.05, 0.1, 0.2, 0.3 and 0.4) were used. Data were fitted to the Pitzer model and the ion interaction parameters β 0 , β 1 , and C γ were calculated. The osmotic coefficients of the solvent (water + IL), the solvent activity, the excess Gibbs free energy for the system were calculated. The negative sign in the excess free energy for the NaCl + IL+ H 2 O solvent mixture at 298.15 K suggests a spontaneous aggregation of {[Emim][MeSO 3 ] + H 2 O} or {[Emim][EtSO 4 ] + H 2 O}.

The aim of this work is to evaluate the separation of hydrocarbons (hexane and heptane) from their azeotropic mixtures with ethanol using protic ionic liquid (PIL) as extraction solvents. With this goal in mind, PILs were synthesized and their thermal and physical characterization were carried out. Experimental determination of the phase equilibrium for the ternary systems hydrocarbons + ethanol + PIL at 298.15 K and 101.2 kPa were also carried out in order to evaluate the feasibility of this application. The solute distribution ratio and the selectivity were also determined to compare the solvent capacity of these PILs. The NRTL equation was used to correlate the experimental data. Furthermore, this paper provides a comparison of the solvent capacity of these PILs with different extraction solvents (ionic liquids (ILs), ILs mixtures and deep eutectic solvents) available in the literature. Then, a critical review for the separation of these azeotropic mixtures was carried out using the extraction processes data obtained through the simulation using a conventional software.

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Density measurements have been made on aqueous solutions of t-BuEt3NI, s-BuEt3N1, i-BuEt3N1, BudNI and E 4 N 1 at 298,15K from 0,Ol to 0,05m. The apparent molal volumes V 4 calculated from the V2,v (m) plots for the salts show a decrease value: n-BuEt3NI > i-BuEt3NI > s-BuEt3NI > t-BuEt3NI. The data analysis may suggest that the cations with the butyl isomers perform two groups: n-BuEt3N 'and i-BuEt,N+with the highest V,O, and t-BuEt3N ' and s-BuEt3N ' similar to Et4N + one. The peculiarities of the experimental observation may be interpreted as a consequence of the structural effect over the intermolecular forces that affect the solute-water interactions deeply.

Osmotic coefficients of dilute aqueous solutions of ter-BuEt3NI, sec-BuEt3NI, iso-BuEt3NI, Bu2Me2NI, and Bu3EtNI are measured by the isopiestic method at 298.15 K. A branched isopiestic cell was used. The osmotic coefficients of tetraalkylammonium solutions were analyzed with the Debye–Hückel limiting law. The results show that the osmotic coefficient varies in the following way: Pr3EtNI11 > n-BuEt3NI11 > Me4NI12 > Et4NI11 > ter-BuEt3NI > sec-BuEt3NI > iso-BuEt3NI > Bu2Et2NI > Bu3EtNI. The set of Pitzer parameters b = 1.2, α1 = 2.0 was used. The results were fitted to the Pitzer model, and the parameters β0, β1, and Cγ were calculated. The results was interpreted in terms of solute–solvent interactions.