Mixed Ion and Electron Conducting Ceramics for Gas Sensors

A conventional solid-state synthetic route was used to prepare a mixed conducting double perovskite-type Ba2Ca0.66Nb0.68Fe0.66O6-δ (BCNF66). FTIR study was performed to confirm the chemical stability under 1% CO2, whereas the cross-sectional SEM image was employed to investigate the morphology of the sensor. A comparative study on BCNF66 with and without CO2 in dry synthetic air along with O2 effect was carried out. The significant effect of O2 was observed when CO2 was passed through the sensor in N2. The O2 in dry synthetic air was found to stabilize the CO2 sensor response (current). Furthermore, the addition of ppm level of CO2 in dry synthetic air increased the response

Magnetically Aligned Iron Oxide/Au Nanoparticles Decorated Carbon Nanotube Hybrid Structure as Humidity Sensor

Ye

Correction: Synthesis and characterization of novel Li-stuffed garnet-like Li5+2xLa3Ta2?xGdxO12 (0 ? x ? 0.55): structure–property relationships

Correction for ‘Synthesis and characterization of novel Li-stuffed garnet-like Li5+2xLa3Ta2?xGdxO12 (0 ? x ? 0.55): structure–property relationships’ by Dalia M. Abdel Basset, et al., Dalton Trans., 2017, 46, 933–946

Magnetically Aligned Iron Oxide/Gold Nanoparticle-Decorated Carbon Nanotube Hybrid Structure as a Humidity Sensor

Functionalized carbon nanotubes (f-CNTs), particularly CNTs decorated with nanoparticles (NPs), are of great interest because of their synergic effects, such as surface-enhanced Raman scattering, plasmonic resonance energy transfer, magnetoplasmonic, magnetoelectric, and magnetooptical effects. In general, research has focused on a single type of NP, such as a metal or metal oxide, that has been modified on a CNT surface. In this study, however, a new strategy is introduced for the decoration of two different NP types on CNTs. In order to improve the functionality of modified CNTs, we successfully prepared binary NP-decorated CNTs, namely, iron oxide/gold (Au) NP-decorated CNTs (IA-CNTs), which were created through two simple reactions in deionized water, without high temperature, high pressure, or harsh reducing agents. The physicochemical properties of IA-CNTs were characterized by ultraviolet/visible spectroscopy, Fourier transform infrared spectroscopy, a superconducting quantum interference device, scanning electron microscopy, and transmission electron microscopy. In this study, IA-CNTs were utilized to detect humidity. Magnetic IA-CNTs were aligned on interdigitated platinum electrodes under external magnetic fields to create a humidity-sensing channel, and its electrical conductivity was monitored. As the humidity increased, the electrical resistance of the sensor also increased. In comparison with various gases, for example, H₂, O₂, CO, CO₂, SO₂, and dry air, the IA-CNT-based humidity sensor exhibited high-selectivity performances. IA-CNTs also responded to heavy water (D₂O), and it was established that the humidity detection mechanism had D₂O-sensing capabilities. Further, the humidity from human out-breathing was also successfully detected by this system. In conclusion, these unique IA-CNTs exhibited potential application as gas detection materials

Thermochemical CO2 splitting using double perovskite-type Ba2Ca0.66Nb1.34-xFexO6-δ

A carbon-neutral fuel is desired when it comes to solving the issues associated with climate change. A smart approach would be to develop new materials to produce such fuels, which could be integrated with renewables to improve the efficiency (e.g., solid oxide fuel cells (SOFCs) in smart grid and concentrated solar fuel technologies). In this study, we report the utilization of nonstoichiometric perovskite oxides, BaCaNbFeO (BCNF) (0 ≤ x ≤ 1), to split CO into carbon, carbon monoxide, and oxygen at elevated temperatures. Powder X-ray diffraction shows the chemical stability of double perovskite-type BCNF after being exposed to 2000 ppm CO in Ar at 700 °C. Furthermore, all x ≤ 0.66 BCNF members exhibit high chemical stability even under pure CO at 700 °C. Scanning electron microscopy coupled with energy dispersive X-ray, Raman spectroscopy, temperature programmed oxidation (TPO) and mass spectroscopy (MS), and DFT analyses confirm the formation of solid carbon upon CO exposure, which increases with increasing Fe in BCNF. Mössbauer spectroscopy of the as-prepared BCNF shows the presence of Fe, Fe and Fe. Upon Ar exposure, the higher valent Fe component is reduced to Fe and subsequent oxidation of Fe seems to promote the CO reduction. Overall, these promising results of BCNFs, displaying redox activity at significantly lower temperatures compared to state-of-the-art ceria for CO reduction, show great potential for their use in renewable-driven fuel technologies.Peer Reviewe