Investigation of the Thermophysical Properties of AMPS-Based Aprotic Ionic Liquids for Potential Application in CO₂ Sorption Processes

The thermophysical properties such as density, refractive index, and viscosity of five aprotic ILs bearing imidazolium (1-ethyl-3-methylimidazolium [emim], 1-butyl-3-methylimidazolium [bmim], 1-benzyl-3-methylimidazolium [bnmim]), pyrrolidinium (1-butyl-1methylpyrrolidinium [bmpyr]), and pyridinium (<i>N</i>-butylpyridinium [bpyn]) cations with 2-acryloamido-2-methylpropanesulfonate [AMPS] anion were studied, and their effect on CO₂ solubility was explored. The density and viscosity were determined within the temperature range of (293.15 to 363.15) K at atmospheric pressure, while refractive indices were measured within the temperature range of (288.15 to 333.15) K. Among imidazolium cations, increasing the side chain length resulted in increased refractive index and viscosity with a corresponding decrease in density. In the presented ILs, [emim]­[AMPS] showed the highest density and least viscosity over the entire temperature range and an enhanced CO₂ dissolution of 0.40 mole fraction at 1 MPa was observed at 298.15 K. Moreover, the Henry’s constant of [emim]­[AMPS] was determined to be 1.957 MPa which was 49.5, 65.5, 21, and 53% less than [bmim]­[AMPS], [bnmim]­[AMPS], [bmpyr]­[AMPS], and [bpyn]­[AMPS], respectively. The present study provides a better understanding of the structure–activity relationship between CO₂ sorption and physicochemical properties of studied ILs

Core–Shell Vanadium Modified Titania@β-In₂S₃ Hybrid Nanorod Arrays for Superior Interface Stability and Photochemical Activity

Core–shell rutile TiO₂@β-In₂S₃ and modified V-TiO₂@β-In₂S₃ were synthesized to develop bilayer systems to uphold charge transport via an effective and stable interface. Morphological studies revealed that β-In₂S₃ was deposited homogeneously on V-TiO₂ as compared to unmodified TiO₂ nanorod arrays. X-ray photoelectron spectroscopy (XPS) and electron energy loss spectrometry studies verified the presence of various oxidation states of vanadium in rutile TiO₂ and the vanadium surface was utilized for broadening the charge collection centers in host substrate layer and hole quencher window. Subsequently, X-ray diffraction, high-resolution transmission electron microscopy, and Raman spectra confirmed the rutile phases of TiO₂ and modified V-TiO₂ along with the phases of crystalline β-In₂S₃. XPS valence band study explored the interaction of valence band quazi Fermi levels of β-In₂S₃ with the conduction band quazi Fermi levels of modified V-TiO₂ for enhanced charge collection at the interface. Photoelectrochemical studies show that the photocurrent density of V-TiO₂@β-In₂S₃ is 1.42 mA/cm² (1.5AM illumination). Also, the frequency window for TiO₂ was broadened by the vanadium modification in rutile TiO₂ nanorod arrays, and the lifetime of the charge carrier and stability of the interface in V-TiO₂@β-In₂S₃ were enhanced compared to the unmodified TiO₂@β-In₂S₃. These findings highlight the significance of modifications in host substrates and interfaces, which have profound implications on interphase stability, photocatalysis and solar-fuel-based devices