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Herein, to enhance selective detection of NO2 and SO2 using a single device, an ultraviolet (UV) light activated gas sensor has been reported based on reduced graphene oxide (rGO) functionalized with hollow SnO2 nanofibers (NFs) at room temperature. The porous hollow SnO2 NFs are synthesized using electrospinning and calcination treatment, then different contents of SnO2 are introduced to rGO for preparation of rGO/SnO2 nanocomposites by facile magnetic stirring and ultrasonic treatment. The rGO/SnO2 samples reveal obvious sensing response, great reversibility and good humidity resistance to target gases at ppm level. Under different intensities of UV light illumination, gas sensing properties of rGO/SnO2 are studied to explore the photoexcited sensing behaviors. The greatly enhanced selective detection to NO2 (102%) and SO2 (11%) is achieved with a response ratio of 9.3 by using UV light illumination. The results show sensor response and selectivity can be improved using appropriate intensity of excitation light, demonstrating significant modulation effect of UV light assistance on gas detection. The mechanism may be attributed to light motivated electron-hole pairs due to built-in electric fields under UV light illumination, which can be captured by target gases and lead to UV controlled gas sensing performance.

Aurivillius phase BaBi4Ti4O15 micro-sized powders were produced by solid-state reaction and their photocatalytic properties were reported for the first time. X-ray diffraction revealed the ...

Single phase Bi3Nb1.125Fe0.0625Co0.0625Ti0.75O9 ceramics with grain-oriented microstructure were prepared using spark plasma sintering. The ferroelectricity was confirmed by the piezoelectric activity of the ceramics measured at room temperature (d33 = 5.6 pC/N). The magnetic measurements evidenced an antiferromagnetic behaviour which can be ascribed to the superexchange interaction of Fe3+-O-Fe3+ and Co3+-O-Co3+. The ferroelectric Curie point and the antiferromagnetic Neel temperature of the ceramic were identified at 1155 K and 153 K, respectively. The material shows multiferroic behaviour below 153 K.

To improve dielectric, piezoelectric and ferroelectric properties of Sr2Bi4Ti5O18 ceramics, highly textured, dense ceramics are required. Highly grain-oriented Sr2Bi4Ti5O18 textured ceramics were prepared by pressure-assisted spark plasma sintering. The textured ceramics exhibited crystallographic anisotropy with c-axis oriented grains (Lotgering factor of 71%). The dielectric permittivity, piezoelectric constant and ferroelectric remnant polarization measured on the ceramics in the direction perpendicular to the pressure applied during sintering are higher than those along the parallel direction. These improved properties are related to the preferred polarization rotation in the textured microstructures prepared during spark plasma sintering.

This study proposes a new process to synthesize zero-valent iron/biochar (Fe0-BC) by carbothermal reduction using wood waste and iron mud as raw materials under different temperature. The characterization results showed that the Fe0-BC synthesized at 1200ºC (Fe0-BC-1200) possessed favorable adsorption capacity with the specific surface area of 103.18 m2/g, and that the zero-valent iron (Fe0) particles were uniformly dispersed on the biochar surface. The removal efficiency of rhodamine B (RB) was determined to evaluate the performance of the prepared Fe0-BC. Fe0-BC-1200 presented the best performance on RB removal, which mainly ascribe to that more Fe0 particles generated at higher temperature. The equilibrium adsorption capacity reached 49.93 mg/g when the initial RB concentration and the Fe0-BC-1200 dosage were 100 mg/L and 2g/L, respectively, and the pseudo-second-order model was suitable to fit the removal experimental data. LCMC and XRD analyses revealed that the removal mechanism included the physical adsorption of biochar and the redox reaction of Fe0. Moreover, copper existed in the iron mud was also reduced to Cu0, which was beneficial to catalyze the oxidation of iron, the degradation of RB was promoted at the same time.

E-textiles are gaining growing popularity recently due to low cost, light weight, and conformable compatibility with clothes in wearable and portable smart electronics. Here, an easy-handing, low cost, and scalable fabricating strategy is reported to fabricate conductive, highly flexible, and mechanically stretchable/twisted fiber gas sensor with great wearability and knittability. The proposed gas sensor is built using commercially available cotton/elastic threads as flexible/stretchable templates and reduced graphene oxide/mesoporous zinc oxide nanosheets as sensing layers to form conducting fibers. The as-prepared fiber demonstrates sensitive sensing response, excellent long-term stability (84 days), low theoretical detection limit (43.5 ppb NO

Room-temperature NO

Room-temperature NO2 gas sensors are fabricated by employing tin oxide (SnO2) nanofibers (NFs) as sensing layers and low-dimension carbon nanomaterials, including single-walled carbon nanotubes (SWCNTs) and reduced graphene oxide (rGO), as conductive interdigital electrodes (IDEs). The morphology characteristics and gas sensing performance of rGO IDEs-SnO2 and SWCNTs IDEs-SnO2 gas sensors have been investigated. The results demonstrate that the response of rGO IDEs based sensors achieves 90.0% after been exposed to 12 ppm NO2, which is superior to the responses of Ti/Au and SWCNTs IDEs based sensors (55.1% and 16.7%, respectively). The rGO IDEs-SnO2 sensor exhibits excellent sensitivity, large recovery capability and repeatability, and high selectivity at room temperature. The sensing mechanism of such prominent performance has also been analyzed, revealing that the outstanding properties could be attributed to a large number of active adsorption sites, the formation of a p-n heterojunction and a large effective contact area between the two-dimensional rGO nanosheets and the tube-shaped SnO2 NFs. This work helps to build up a potential platform to explore effective electrodes for future novel NO2 gas sensors in practical gas sensing applications.