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The steadily increasing concentration of carbon dioxide (CO2) gas in the atmosphere is a significant environmental problem in modern society. Henceforth, there is triggering interest in the new technological solutions for CO2 monitoring. This work reports the fabrication of a novel, low cost, chemiresistive carbon dioxide sensor based on the PVA/[EMIM][SCN] based ionogel membrane. Here, the lightweight transparent ionogel membrane with enhanced ionic conductivity is acted as the electrically conductive region of the sensor. The response rate of the CO2 sensor was monitored in terms of direct as well as alternating current resistance using a high-precision multimeter and an impedance spectroscopy, respectively. The CO2 desorption kinetics were also studied to check the reliability of the sensor using the conductometric approach. The selectivity of the sensor for CO2 gas was well evidently quantified by comparing the response rate of the sensor with both CO2 and N2 gases. The optical microscopic images were periodically taken before and after CO2 exposure in conjunction with the conductivity data revealed the physisorption mechanism of the sensor. The upshots presented herein will promote the development of an organic CO2 gas sensor, which will be worthwhile for numerous industrial and practical applications and for air quality control in the future. [ABSTRACT FROM AUTHOR]

Abstract: A new superionic conducting transparent phosphate glasses with composition Li(4+x)Ti x Nb1−x P3O12 (0 ≤ x ≤ 1.0) were prepared by rapid melt quenching. As quenched samples were characterized by X-ray powder diffraction, differential scanning calorimetric and Fourier transform infrared spectroscopy studies. These glasses were found to have high thermal stability parameter and Li4NbP3O12 has been found to have high glass forming ability. Electrical properties of the present glasses were studied by impedance and dielectric spectroscopy in the frequency range 10 Hz–3 MHz in the temperature range 323–523 K. Arrhenius behavior has been observed for all the glass in conductivity, dielectric loss and conductivity relaxation and their activation energies are explained and reported. [Copyright &y& Elsevier]

• Mixed ionic effect in (Li (1-x) Na x) 5 TiP 3 O 12 glass through thermal parameters, GFA, GS was spoted. • Stength of mixed ion in glass transition temperatures and dc conductivity was estimated. • Mixed alkali content in glassy phase plays a vital role in ionic transport and hopping relaxation. • Different conductivity spectra and electrical modulus scaling were exposed. • Dixon scaling is better in electrical modulus scaling. A NASICON based phosphate glass systems (Li (1-x) Na x) 5 TiP 3 O 12 with various composition x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0 were synthesized by melt quenching method. X-ray diffraction patterns substantiate the amorphous nature. The mixed alkali effect (MAE) was explicated in thermal studies as well as in dielectric spectroscopy. The thermal analysis demonstrates that the series exhibit a MAE in their characteristic thermal parameters also. The dynamics of the ions in mixed alkali glass illustrate miniaturization of dc conductivity and maximum in their respective activation energy at x = 0.6. This decrease in conductivity in the glass composition is observed in all temperature range 273 K to 473 K and follows the same manner as glass transition temperature. The frequency dependence ac conductivity, as well as the electric modulus espouse a few interesting aspects of scaling regarding MAE. [ABSTRACT FROM AUTHOR]

Highlights: [•] Solution combustion technique and preparation of nanocrystalline olivine materials. [•] Olivine type LiNiPO4 based nanocrystalline materials and characterization. [•] AC electrical studies on olivine type LiNi1−x M x PO4(M=Cu2+/Mg2+)based materials. [•] Enhancement of ionic conductivity in the nanocrystalline phase of LiNiPO4 material. [Copyright &y& Elsevier]

Abstract: A typical Ce0.85Gd0.15O2−δ (GDC15) composition of CeO2−Gd2O3 system is synthesized by modified sol−gel technique known as citrate-complexation. TG–DTA, XRD, FT-IR, Raman, FE-SEM/EDX and ac-impedance analysis are carried out for structural and electrical characterization. XRD pattern confirmed the well crystalline cubic fluorite structure of GDC15 after calcining at 873K. Raman spectral bands at 463, 550 and 600cm−1 are also in agreement with these structural features. FE-SEM image shows well-defined grains separated from grain boundary and good densification. Ac-impedance studies reveal that GDC15 has oxide ionic conductivity similar to that reported for Ce0.9Gd0.1O2−δ (GDC10) and Ce0.8Gd0.2O2−δ (GDC20). Ionic and electronic transference numbers at 673K are found to be 0.95 and 0.05, respectively. This indicates the possible application of GDC15 as a potential electrolyte for IT-SOFCs. [Copyright &y& Elsevier]

Highlights: [•] Ce1 − x Sr x O2 − δ (x =0.05–0.2) were synthesized by citrate-complexation method. [•] Pure solid solution was found for x =0.05 unlike other compositions. [•] Raman spectra confirms the existence SrCeO3 secondary phase for x >0.05. [•] Conductivity decreases with increase in x for Ce1 − x Sr x O2 − δ (x =0.05–0.2). [•] Sr-doped ceria here showed higher conductivity when compared to rare-earth doped ceria. [Copyright &y& Elsevier]

Highlights: [•] Ln doped CeO2 was successfully synthesized by citrate-complexation method. [•] Unit cell parameter increases with increase in dopant radius. [•] Densities based on oxygen vacancy model agreed with the experimental results. [•] Raman spectroscopy confirms the formation of Ce0.8Ln0.2O2−δ solid solutions. [•] Ce0.8Sm0.2O2−δ exhibits the highest oxygen ionic conductivity. [Copyright &y& Elsevier]