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[Display omitted] • Decreasing Ce/Zr molar ratio improves the thermal stability and catalytic activity. • Increasing Ce/Zr molar ratio within 0.89 ∼ 1.44 clearly inhibits the growth of Pt particles. • The main factor affecting catalyst activity is the valence state of Pt. The synthesis of Pt-supported catalysts with high stability faces an enormous challenge, especially for applications in high-temperature environments. Here we attempt to improve the catalytic activity and thermal stability of Pt-supported catalyst via modulating Ce/Zr molar ratio. The crystalline structure, texture and metal dispersion of the Pt/Ce x Zr 1-x samples were studied by XRD, Raman, XPS, HRTEM and H 2 -TPR. The results indicate that decreasing Ce/Zr molar ratio can improve the thermal stability, the reducibility of surface lattice oxygen of the catalyst, and enhance the oxygen vacancy content. On the contrary, a higher Ce/Zr molar ratio facilitates the interaction between Pt and CeO 2 and inhibits the growth of Pt particles thereby maintaining high Pt dispersion. The Pt/Ce x Zr 1-x catalysts with Ce/Zr molar ratio of ∼1.0 might exhibited the best overall catalytic performance within long-term use. The effect of the valence state of Pt on catalytic activity is greater than that of the Pt dispersion. Our findings contribute to a depth understanding of Pt/CeZr catalysts and provide insights into the design of more efficient and durable catalysts for automotive exhaust purification. [ABSTRACT FROM AUTHOR]

Development of high performance room temperature sensors remains a grand challenge for high demand of practical application. Metal oxide semiconductors (MOSs) have many advantages over others due to their easy functionalization, high surface area, and low cost. However, they typically need a high work temperature during sensing process. Here, p-type sensing layer is reported, consisting of pore-rich dumbbell-like Co 3 O 4 particles (DP-Co 3 O 4 ) with intrinsic high catalytic activity. The gas sensor (GS) based DP-Co 3 O 4 catalyst exhibits ultrahigh NH 3 sensing activity along with excellent stability over other structure based NH 3 GSs in room temperature work environment. In addition, the unique structure of DP-Co 3 O 4 with pore-rich and high catalytic activity endows fast gas diffusion rate and high sensitivity at room temperature. Taken together, the findings in this work highlight the merit of integrating highly active materials in p-type materials, offering a framework to develop high-sensitivity room temperature sensing platforms. [ABSTRACT FROM AUTHOR]

Abstract: A multifunctional heterojunctioned K-OMS-2/TiO2/Fe3O4 (KTF) nanocomposite was successfully synthesized using a combination of hydrothermal and co-precipitation techniques. The resultant sample was characterized by XRD, FESEM, TEM, N2 adsorption, XPS and VSM. Its photocatalytic activity was demonstrated in the photocatalytic degradation of humic acid (HA). Morphology characterization showed the hierarchical structure of the synthesized material, and XRD results revealed that both the rutile and anatase TiO2 structures are present in the sample. The average pore diameters and BET surface area of the synthesized KTF heterojunctions were 40nm and 134.42m2/g, respectively. XPS spectra confirmed the presence of Fe3O4 and TiO2 in the synthesized material, and the valences of Mn were kept at +3 and +4 after the grafting of Fe3O4 and TiO2. The synthesized material showed good magnetic response and photocatalytic activity under simulated solar light irradiation, and 85.7% of HA was decomposed after 120min in the presence of KTF nanocomposites. The reusability study suggested that the magnetic recovered material was stable enough for multiple recycling usages, verifying its potential application in water purification. [Copyright &y& Elsevier]

Abstract: A novel hybrid process combining β-MnO2 nanowires oxidation and microfiltration was adopted to remove bisphenol A (BPA), an endocrine disrupting chemical (EDC) in the aquatic environment. The β-MnO2 nanowires synthesized via a facile hydrothermal method were characterized by X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscope, and nitrogen sorption. It was demonstrated that β-MnO2 nanowires can degrade BPA effectively. Investigation on operation parameters indicated that oxidation of BPA using β-MnO2 nanowires was evidently dependent on pH, while humic acid and coexisting metal ions such as Ca2+, Mg2+, and Mn2+ induced suppressive effects. After oxidation, a crossflow microfiltration process was conducted to efficiently separate and recover the β-MnO2 nanowires from treated water. Membrane fouling study showed that the as-synthesized β-MnO2 nanowires possess excellent mechanical stability and was able to retain the 1D structure with high aspect ratios after reaction, thus significantly reducing membrane pore blocking in the microfiltration process. [Copyright &y& Elsevier]

Abstract: N-type Fe2O3 nanobelts and P-type LaFeO3 nanobelts were prepared by electrospinning. The structure and micro-morphology of the materials were characterized by X-ray diffraction (XRD) and scanning of electron microscopy (SEM). The gas sensing properties of the materials were investigated. The results show that the optimum operating temperature of the gas sensors fabricated from Fe2O3 nanobelts is 285°C, whereas that from LaFeO3 nanobelts is 170°C. Under optimum operating temperatures at 500ppm ethanol, the response of the gas sensors based on these two materials is 4.9 and 8.9, respectively. The response of LaFeO3-based gas sensors behaves linearly with the ethanol concentration at 10–200ppm. Sensitivities to different gases were examined, and the results show that LaFeO3 nanobelts exhibit good selectivity to ethanol, making them promising candidates as practical detectors of ethanol. [Copyright &y& Elsevier]

Abstract: Large-scale uniform nutlike ZnO microcrystals are successfully synthesized via a facile hydrothermal process at low temperature (95 °C). The structure and morphology of the ZnO products are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results reveal that the as-prepared ZnO products have average length of 2.2 µm and diameter of 1.8 µm, possessing a single crystal wurtzite structure. The possible formation mechanism of nutlike microcrystals is proposed. The samples exhibit excellent ethanol sensing properties at the operating temperature of 250 °C detecting ethanol as low as 1 ppm. [Copyright &y& Elsevier]

Abstract: KCl-doped ZnO nanofibers are synthesized via an electrospinning method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The humidity sensing properties of these nanofibers are investigated by screen-printing them on a ceramic substrate with a pair of Ag–Pd interdigitated electrodes. The experimental results show that the 5.7wt% KCl-doped ZnO nanofibers hold super-rapid response and recovery, high response value, good reproducibility, linearity, selectivity, and stability at 100Hz. Especially, the response time and recovery time is only about 2 and 1s, respectively. These results demonstrate the potential application of KCl-doped ZnO nanofibers for fabricating high performance humidity sensors. [Copyright &y& Elsevier]

Abstract: Cu–Zn/ZnO nanocomposites with a novel core-shell structure have been prepared by a surface precipitation process in aqueous solution. X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy are employed to analyze the structure and morphology of the present products. The influence of the annealing temperature on the core-shell structure of the nanocomposites is investigated, and a possible growth model is proposed. Furthermore, the gas sensors based on the Cu–Zn/ZnO nanocomposites are fabricated and tested, which exhibits high sensitivity and fast response to CO. The best results are obtained for the sensor based on the film annealed at 350°C, which shows that the sensitivity is about 6.3 when the sensor is exposed to 100ppm CO at the operating temperature of 240°C. The possible sensing mechanism of the Cu–Zn/ZnO sensing film has also been discussed. [Copyright &y& Elsevier]

Abstract: Dumbbell-like ZnO microcrystals have been obtained through a facile solution method. The structure, morphology and optical properties of the as-prepared ZnO microcrystals have been characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy and photoluminescence. The as-prepared ZnO microcrystals exhibit excellent sensing properties against acetone at an operating temperature of 300°C. The response and recovery times are found to be 1.5 and 3s, respectively. Moreover, the sensor holds the successful discrimination between acetone and ethanol, which makes our product a good candidate in fabricating highly selective sensors in practice. [Copyright &y& Elsevier]

Abstract: Pure and Sm2O3-doped SnO2 are prepared through a sol–gel method and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The sensor based on 6wt% Sm2O3-doped SnO2 displays superior response at an operating temperature of 180°C, and the response magnitude to 1000ppm C2H2 can reach 63.8, which is 16.8 times larger than that of pure SnO2. This sensor also shows high sensitivity under various humidity conditions. These results make our product be a good candidate in fabricating C2H2 sensors. [Copyright &y& Elsevier]

Eleven alkaloids including four previously undescribed oxoisoaporphine alkaloids, menisoxoisoaporphines A-D (1 – 4), four known analogues (5 – 8), and three aporphine alkaloids (9 – 11), were isolated and identified from the rhizomes of Menispermum dauricum. Their structures were elucidated by extensive spectroscopic data and single-crystal X-ray diffraction analyses. Among them, compounds 1 and 4 were the first samples of oxoisoaporphine with C-6 isopentylamino moiety, and 2 was a rare C-4 methylation product of oxoisoaporphine alkaloid. The in vitro anti-inflammatory activity of compounds 1 – 11 was performed by evaluating the inhibition of NO level in LPS-induced RAW264.7 macrophages. Among them, compound 4 exhibited the most potent NO inhibition activity with an IC 50 value of 1.95 ± 0.33 μ M. The key structure-activity relationships of those oxoisoaporphine alkaloids for anti-inflammatory effects have been summarized. Four undescribed oxoisoaporphine alkaloids, together with seven known analogues were isolated from the rhizomes of Menispermum dauricum DC., which were evaluated for their their inhibitory activity towards the LPS-induced NO production in RAW 264.7 cells. Menisoxoisoaporphine D exhibited the most potent NO inhibition activity with an IC 50 value of 1.95 ± 0.33 μM. [Display omitted] • Four undescribed alkaloids were isolated from the rhizomes of Menispermum dauricum. • Menisoxoisoaporphine A was the first sample of oxoisoaporphine with C-6 isopentylamino moiety. • Menisoxoisoaporphine B was a rare C-4 methylation product of oxoisoaporphine alkaloid. • Menisoxoisoaporphine D showed the most potent NO inhibition activity (IC 50 1.95 ± 0.33 μM). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • In this work, the obtained Zn 2 SnO 4 -RGO hybrids exhibited outstanding sensing performance for detecting oxidizing gases (NO 2 and O 3) with very low cross sensitivities to reducing gases, such as C 2 H 5 OH, CH 3 COCH 3 and CO. • The Zn 2 SnO 4 -RGO based sensors exhibited high response values of up to 3.50 for 500 ppb NO 2 , which is higher than that for detection of 500 ppb O 3 (1.78) at 30 °C under 50% relative humidity (RH). • The surface reaction between Zn 2 SnO 4 -RGO hybrids and NO 2 can be concluded from Operando diffuse reflectance infrared Fourier transformed spectroscopy (Operando DRIFT). Abstract Highly selective oxidizing gas sensors are of great importance for environmental pollution monitoring. In this work, a hybrid material containing Zn 2 SnO 4 nanoparticles (NPs) and immobilized reduced graphene oxide (Zn 2 SnO 4 -RGO) was developed as a high performance gas sensing material for the detection of ppb-levels of oxidizing gases (NO 2 and O 3). The structural, morphological and compositional properties of the Zn 2 SnO 4 -RGO hybrids were systematically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), which demonstrated the successful anchoring of Zn 2 SnO 4 NPs on RGO nanosheets. The obtained Zn 2 SnO 4 -RGO hybrids exhibited outstanding sensing performance for detecting oxidizing gases (NO 2 and O 3) with very low cross sensitivities to reducing gases, such as C 2 H 5 OH, CH 3 COCH 3 and CO. The Zn 2 SnO 4 -RGO based sensors exhibited high response values of up to 3.50 for 500 ppb NO 2 , which is higher than that for detection of 500 ppb O 3 (1.78) at 30 °C under 50% relative humidity (RH). Moreover, the NO 2 sensing performances of Zn 2 SnO 4 -RGO-based sensors were investigated under various RH. In all cases, the sensors based on RGO and Zn 2 SnO 4 -RGO hybrids presented p-type behavior. The sensors based on Zn 2 SnO 4 -RGO hybrids also exhibited high response values of up to 3.62 for 1 ppm NO 2 at 50 °C in 80% RH, which is much higher than that of pure RGO (1.31). The excellent sensing performances are mainly ascribed to the synergetic effect of Zn 2 SnO 4 NPs and RGO. Furthermore, the surface reaction between Zn 2 SnO 4 -RGO hybrids and NO 2 can be concluded from Operando diffuse reflectance infrared Fourier transformed spectroscopy (Operando DRIFT). [ABSTRACT FROM AUTHOR]

Doping and high specific area are essential to the performance of supercapacitor electrode materials. However, the conventional single doping in two dimensional electrode materials is still unable to get high supercapacitive performance. Here we report a facile hydrothermal process using ammonia as a source of nitrogen (N) and thiourea as a sulfur (S) source to prepare N/S co-doped three dimensional (3D) graphene hydrogel (N/S-3DGH) for supercapacitor electrode application. The as-prepared N/S-3DGH is uniform and stable. The N/S co-doped 3DGH electrode material exhibits a high specific capacity of 1063 Cg -1 at a current density of 1 Ag -1 . Even at a density of 20 Ag -1 , it can still hold an excellent charge and discharge cycling stability, and with 76% of initial capacity retained after 6000 charge and discharge cycles at a density of 10 Ag -1 . Moreover, the all-symmetric solid-state supercapacitor fabricated by N/S-3DGH without any binders owned an energy density of 6.25 Wh kg −1 at a power density of 500 W kg −1 showing very promising applications for portable power and flexible energy storage devices. [ABSTRACT FROM AUTHOR]

In this work, core-shell WO 3 -SnO 2 (CS-WS) nanofibers (NFs) have been successfully synthesized via a coaxial electrospinning approach. The structure and morphology characteristics of the resultant products were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectra (XPS). To investigate the sensing mechanism of the CS-WS NFs, sensors based on SnO 2 NFs, WO 3 NFs, and SnO 2 -WO 3 composite NFs were fabricated respectively, and their gas sensing properties were investigated by using CO, ethanol, toluene, acetone, and ammonia as the test gas. The results indicated that the CS-WS NFs exhibited a good response to ethanol (5.09 at 10 ppm) and short response/recovery time (18.5 s and 282 s) compared with the other test gases. The enhanced ethanol sensing properties of CS-WS NFs compared with those of SnO 2 NFs were closely associated with the CS structure and its derivative effect due to the different work function of SnO 2 and WO 3 . The approach proposed in this study may contribute to the realization of more sensitive metal oxide semiconductor (MOS) core-shell heterostructure sensors. [ABSTRACT FROM AUTHOR]

Transition metal oxides have attracted considerable attention as anode materials of lithium-ion batteries (LIBs). However, poor electrical conductivity and huge volume change hinder their practical application. Porous nanostructure is vital to attain high-performance lithium-ion batteries. Herein, we have designed and fabricated regularly porous ZnFe 2 O 4 nanospheres consisted of small primary nanoparticles via a facile hydrothermal method followed by calcination. The structural properties and morphology of the sample are characterized by powder X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The composite is then evaluated as anode for Li-ion battery and shows excellent electrochemical properties. The reversible capacity of 868.9 mAh g −1 can be obtained at 200 mA g −1 over 80 cycles. Furthermore, the discharge capacity can still retain 456 mAh g −1 after 600 cycles at a high charge rate of 2 A g −1 . Our findings reveal that ZnFe 2 O 4 sample is a promising anode material for LIBs due to its superior rate capability and long cycle life. [ABSTRACT FROM AUTHOR]

A reticular 3D energetic metal-organic framework, sodium 1,1′-dinitramino-5,5′-bistetrazolate was first synthesized and fully characterized by crystal X-ray diffraction, elemental analysis, mass spectrometry, IR spectroscopy, differential scanning calorimetry (DSC) and sensitivity test. It shows a density of 1.892 g·cm −3 , a positive oxygen balance and a high decomposition temperature of 250 °C. The promising energetic properties were also investigated by using theoretical calculation methods. Its calculated heat of formation (529.5 kJ·mol −1 ) combined with impressive heat of detonation (5080 kJ·kg −1 ), good thermal stabilities and clean detonation products make it a competitive replacement as a green energetic material. [ABSTRACT FROM AUTHOR]

Pt-loaded mesoporous WO 3 was fabricated by nanocasting method. Mesoporous structure provided ordered tunnel which was convenient for gas diffusion and the large specific surface area which could offer more active sites. The noble metal (Pt) improved the catalytic efficiency which played crucial role in enhancing the performance of the gas sensor. The obtained materials were characterized by X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Characterization indicated that the synthesized materials had ordered mesoporous structure with excellent crystallinity and the pore size was about 10.6 nm. Static test system was employed to measure ammonia sensing properties for the as-prepared samples. The sensor based on Pt-loaded WO 3 presented higher sensitivity, quicker response-recovery rates, excellent repeatability and selectivity. It indicated that the Pt-loaded mesoporous WO 3 was a potential ammonia gas sensor material. [ABSTRACT FROM AUTHOR]

The development of graphene-based room temperature gas sensors has drawn massive attention due to their unique advantage of gas sensing at room temperature. In this paper, in pursuit of developing high-performance graphene-based gas sensors, a NO 2 gas sensor has been successfully fabricated using sulfonated reduced graphene oxide (S-rGO) anchoring with SnO 2 nanoparticles as sensing materials. The SnO 2 nanoparticles modified S-rGO (SnO 2 /S-rGO) hybrids were prepared by deposition of SnO 2 nanoparticles on the surface of S-rGO through hydrothermal synthesis method. The combined characterizations of X-ray diffraction, UV–vis spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, energy-dispersive spectroscopy, as well as N 2 sorption isotherm indicate the successful preparation of SnO 2 /S-rGO hybrids with porous structure. Most importantly, SnO 2 /S-rGO hybrids exhibit good sensing performances for detection of NO 2 at room temperature, such as high response, fast response and recovery rate, and good selectivity. The sensor based on SnO 2 /S-rGO hybrids exhibits better sensing performances than the previously reported rGO-based gas sensors. Furthermore, the excellent sensing performances of sensor based on SnO 2 /S-rGO also render it suitable for development of high performance gas sensors operated at room temperature. [ABSTRACT FROM AUTHOR]

Lithium chloride (LiCl)-loaded 3D cubic mesoporous silica KIT-6 (LiCl-KIT-6) composites were prepared as resistance-type humidity-sensitive materials. The structures of the resultant composites were characterized by X-ray diffraction, N 2 adsorption–desorption, and transmission electron microscopy. The humidity sensors based on LiCl-KIT-6 composites were fabricated and the sensing properties were investigated. Results indicate the uniform pore distribution of KIT-6 contributes to the rapid hydrone transport in mesoporous channels. The impedance of optimized 3 wt% LiCl-KIT-6 sensor changed by more than three orders of magnitude over the relative humidity range of 11–95%. The response and recovery times of the sensor were 15 s and 28 s, respectively. Finally, the complex impedance method was used to analyze the humidity sensing mechanism of the sensor based on LiCl-KIT-6. [ABSTRACT FROM AUTHOR]

A facile and effective strategy has been successfully developed to synthesize reduced graphene oxide-multiwalled carbon nanotubes-tin oxide nanoparticles (rGO-CNT-SnO 2 ) hybrids by hydrothermal method. The combined characterizations of X-ray diffraction, Raman spectrum and Transmission electron microscopy were used to characterize the samples thus obtained, indicating the successful preparation of rGO-CNT-SnO 2 hybrids. A room temperature NO 2 sensor was fabricated by dropping the dispersion of rGO-CNT-SnO 2 hybrids on the surface of ceramic substrate previously printed Au electrodes. Most importantly, the sensor based on rGO-CNT-SnO 2 hybrids shows high response, fast response and recovery rate, high selectivity and good stability, which are much better than NO 2 sensors based on pure rGO and rGO-SnO 2 hybrids. [ABSTRACT FROM AUTHOR]

Highly sensitive and selective toluene sensors based on ordered mesoporous Co3O4 have been successfully developed. The combined characterizations of X-ray diffraction (XRD) patterns, nitrogen adsorption–desorption isothermal, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) indicate that mesoporous Co3O4 with ordered mesoporous structure and high surface area has been successfully prepared by the nanocasting method using mesoporous silica (SBA-15) as hard template and Co(NO3)2·6H2O as cobalt source. It is also found that mesoporous Co3O4 thus obtained shows good response toward toluene with the concentrations ranging from 1ppm to 1000ppm. Furthermore, mesoporous Co3O4 also exhibits high selectivity for detection of toluene, compared to other interferences, such as ethanol, formaldehyde, ethanol, acetone, methanol and ammonia. Most importantly, mesoporous Co3O4 exhibits better sensing performance than that of non-porous Co3O4 obtained by direct calcination of Co(NO3)2·6H2O in the absence of any templates, which can be attributed to unique properties of mesopotous Co3O4, such as high surface area, open mesoporous structure as well as relatively small crystal size. [ABSTRACT FROM AUTHOR]

Abstract: Mesoporous LaFeO3 with high surface area and pore volume was prepared through a nanocasting route by using mesoporous silica SBA-15 as a hard template. The structure and chemical composition of the sample were characterized by X-ray diffraction (XRD), nitrogen adsorption–desorption, transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS). The humidity sensing properties of the mesoporous LaFeO3 were investigated. Impedance greatly changes by more than five orders magnitude (1.7×106 to 4.5kΩ) when the relative humidity varies from 11% to 98% at 10Hz, and it also exhibits the satisfactory response time, hysteresis and stability. The sensor utilizing mesoporous LaFeO3 via nanocasting method displays superior humidity performance compared to that using bulk LaFeO3 via sol–gel technique. Such sensing behavior of the mesoporous LaFeO3 can be attributed to the high surface area (83.2m2/g) and porosity, which lead to highly effective interaction between the water molecules and the surface active sites. A possible mechanism is discussed to explain the excellent performance of the humidity sensing device using the mesoporous LaFeO3. [Copyright &y& Elsevier]

Abstract: La x Sr1− x FeO3 nanofibers were synthesized via electrospinning and characterized by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The diameters of the La x Sr1− x FeO3 nanofibers produced were in the range of 30–80nm. When the La/Sr ratio was 0.7:0.3, La0.7Sr0.3FeO3 nanofibers showed high and rapid response and good repeatability to 500ppm ethanol. At 185°C, the response and recovery time of La0.7Sr0.3FeO3 nanofiber were 11s and 21s, respectively. The La0.7Sr0.3FeO3 nanofibers are promising sensitive materials for ethanol detecting. [Copyright &y& Elsevier]

Abstract: Uniaxially aligned Ba0.8Sr0.2TiO3 (BST) nanofiber arrays were fabricated via electrospinning combined with annealing. A specially designed collector composed of two paralleled aluminum electrodes and an insulative substrate were used in the electrospinning process. The morphology and structure of the resultant arrays were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The SEM shows well uniaxial arrangement and the diameters before (300–500nm) and after (100nm) calcination. XRD shows well-defined perovskite crystal structure of the as-synthesized arrays. The humidity sensor based on the as-synthesized arrays exhibited a rapid response-recovery property at room temperature. The possible sensing mechanism was proposed. [Copyright &y& Elsevier]

Abstract: SnO2 nanosheets were synthesized by a hydrothermal method at 200°C using stannic chloride hydrate and sodium hydroxide as starting materials. The as-synthesized nanoparticles and nanosheets are characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The gas response, selectivity, and response speed were optimized by varying the morphology of the sensing materials and operation temperature. Most importantly, the SnO2 nanosheets sensor exhibits high response, low detection limit and fast response to ethanol. The gas response of the SnO2 nanosheets to 100ppm ethanol was 39.6 at 300°C, which was 3.6 and 6.1 times higher than that of the nanospheres-like and the nanoparticles, respectively. Response and recovery times were 1 and 9s when the sensor was exposed to 20ppm ethanol at an operating temperature of 300°C. [Copyright &y& Elsevier]

Abstract: Hollow ZnSnO3 microspheres were successfully prepared by hydrothermal method at 160°C for 12h. The prepared material was characterized by field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and X-ray diffraction measurements (XRD). The average diameter of the hollow ZnSnO3 microspheres was in the range of 400–600nm. Compared with solid ZnSnO3 microspheres structure, the hollow ZnSnO3 microspheres showed better response (S) to butane. To 500ppm butane, the sensor response (S) of the hollow ZnSnO3 microspheres was 5.79 at the optimum operating temperature of 380°C, and the response and recovery time were 0.3s and 0.65s, respectively. The sensitivities of sensors based on this material were linear with the concentration of butane in the range of 100–1000ppm. [Copyright &y& Elsevier]

Abstract: K2CO3-SBA-15 with different K2CO3 content was prepared by thermal dispersion. The structures of resultant powders were characterized by XRD, N2 adsorption and IR. The humidity sensing properties of the powders were also investigated. Compared with pure SBA-15, K2CO3-SBA-15 shows improved humidity sensing properties and the introducing level of K2CO3 has a great influence on the humid sensitivity of K2CO3-SBA-15 composites. The optimal mixing ratio was K2CO3-SBA-15 (0.8g/g), which exhibited excellent linearity in the whole range of 11–95%RH, a resistance variation of about five orders of magnitude, and a rapid response time and recovery time about 15 and 50s, respectively. The mechanism of the humidity sensitive properties was also discussed. [Copyright &y& Elsevier]