In2O3 Nanospheres Research Articles

Trimethylamine detection of 3D rGO/mesoporous In2O3 nanocomposites at room temperature

Three-dimensional reduced graphene oxides aerogel-supporting In2O3 nanospheres (3D rGO/In2O3) nanocomposites with high performances were obtained via a hydrothermal method. The structure and morphology of as-obtained 3D rGO/In2O3 nanocomposites were characterized by various techniques. The results showed that the mesoporous In2O3 nanospheres were dispersed on the well-retained 3D rGO network with average diameters approximate of 115 nm, specific surface area of 108.2 m2/g and average pore size of 6 nm, which are beneficial for its detection of trimethylamine (TMA) at room temperature. And the good sensitivity to 100 ppm of TMA was 9.3% at room temperature with the well stability. Also, the sensing performances of TMA exhibited fast response and recovery property, which are 2 s and 11 s, respectively. Meanwhile, the possible improving gas sensing mechanism of as-obtained 3D rGO/In2O3 nanocomposites is illustrated. We believe that the strategy of compositing nanostructured-In2O3 with 3D rGO provides a new insight for the future development of room-temperature gas sensors.

Fabrication of aggregated In2O3 nanospheres for highly sensitive acetaldehyde gas sensors

The selective detection of dangerous and explosive gases with high sensitivity is serious problem to safety of humans and industrial processes. Small sized nanoparticles aggregated into a nanospheres offer plenty of advantages such as large specific area, greater mass transportation, and diffusion of gas molecules deep inside the material towards efficient gas sensing applications. Herein, In2O3 nanoparticles aggregated into nanospheres were synthesized successfully through one step microwave hydrothermal method. The structure, morphology and chemical states of prepared In2O3 nanospheres were studied by XRD, TEM and XPS measurements. Furthermore, obtained In2O3 nanospheres were applied as a gas sensing layer for acetaldehyde (CH3CHO) detection. Acetaldehyde is an important volatile organic compound which is highly reactive, toxic and carcinogenic agent. Gas sensor based on In2O3 nanospheres shows high sensitivity for a wide range of CH3CHO concentration (1–100 ppm). Concentration dependent resistances during the exposure and oxidation reaction of CH3CHO gas were investigated. The obtained results in this work indicate that In2O3 nanospheres are prospective candidates for the fabrication of CH3CHO gas sensors.

Enhanced room temperature gas sensor based on Au-loaded mesoporous In2O3 nanospheres@polyaniline core-shell nanohybrid assembled on flexible PET substrate for NH3 detection

The polyaniline (PANI) and Au-loaded mesoporous In2O3 nanospheres@PANI core-shell nanohybrid (PAInxAy) sensing materials with different amounts of mesoporous In2O3 and Au-loaded mesoporous In2O3 (2–50 mol%) nanospheres were synthesized through combination methods of facile hydrothermal and in-situ chemical oxidative polymerization. The loading amount of Au was varied from 0.5 at% to 2.0 at%. The sensing materials were performed on flexible polyethylene terephthalate (PET) substrate to fabricate the sensing device and investigate the gas sensing performances at room temperature. Various characterization techniques including FESEM, TEM, FTIR, XRD and XPS were performed to identify the morphology, structure and element information of the synthesized materials. The sensing performances demonstrated that the sensor utilizing 1 at% Au-loaded 20 mol% mesoporous In2O3 nanospheres@PANI core-shell nanohybrid (PAIn20A1) showed the highest response value (∼46) to 100 ppm NH3 at room temperature, which were about 14 times and 4 times higher than those of pure PANI and PAIn10. The sensor also exhibited excellent selectivity, good reproducibility and perfect response-concentration linearity to NH3 at room temperature. Besides, the effect of relative humidity on the sensing performance and the sensing mechanism for the sensitivity enhancement were discussed.

Template-free fabrication of hierarchical In2O3 hollow microspheres with superior HCHO-sensing properties

Hierarchical In2O3 hollow microspheres were successfully prepared via a facile and low-cost hydrothermal method. Their morphology and structure were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and the Brunauer-Emmett-Teller (BET) approach. The SEM and TEM results revealed that the as-obtained hollow In2O3 microspheres is composed of In2O3 nanospheres with 200–400 nm in diameter, and the size of In2O3 microspheres is about 2–4 μm. The specific surface area of the as-prepared In2O3 is about 40.94 m2/g. The sensor based on hierarchical In2O3 hollow microspheres displays excellent sensing properties to 10 ppm HCHO, and the optimum operating temperature is relatively low (200 °C). The response value of the as-fabricated sensor to 10 ppm HCHO is about 20. Due to the sensor based on hierarchical In2O3 hollow microspheres has many advantages, such as facile preparation and excellent gas-sensing properties, it has a wide range of prospects in practical applications.

Fabrication of mesoporous In2O3 nanospheres and their ultrasensitive NO2 sensing properties

Ultra-sensitive NO2 sensor based on hierarchical In2O3 nanospheres which are successfully fabricated via facile thermal processes. Such morphology evolution is investigated by the time-dependent experiment. Remarkable features of the mesoporous structure and, large specific area (82.1m2/g) and small sized nanoparticles result in the In2O3 nanospheres a high NO2 sensing efficiency. For the In2O3 based NO2 sensor, temperature of annealing process is an important factor to influence its sensing performance; the rather high sensitivity (360.1, 100ppb) and low detection limit (1ppb) are realized at 120°C for the sample that annealed at 500°C. Based on the preferable sensing performance, the novel In2O3 sensor is believed to be promising to be applied for practised NO2 detecting.

Facile synthesis of nanoparticle packed In2O3 nanospheres for highly sensitive NO2 sensing

Nanoparticle packed In2O3 nanospheres are successfully synthesized via a facile one-step solvothermal method followed by annealing.

Preparation, characterization and photocatalytic activity of juglans-like indium oxide (In2O3) nanospheres

Juglans-like In2O3 nanospheres were successfully synthesized by hydrothermal method and the post-thermal treatment. X-ray diffraction (XRD) revealed that the as-synthesized In2O3 nanospheres had body-centered cubic structure. The scanning electron microscope (SEM) showed In2O3 nanospheres under different experimental conditions. It was observed that both ethylene glycol and ethylenediamine played roles in the synthesis of juglans-like In2O3 nanospheres. The photocatalytic activity of the In2O3 nanospheres was appraised by photocatalytic degradation of Rhodamine B (Rh B) aqueous solution under visible light. The photocatalytic results showed that compared with other samples (sample 1, 2 and 3) in the paper, the juglans-like In2O3 nanospheres (sample 4) exhibited a better photocatalytic activity.

Promoting effects of Ag on In2O3 nanospheres of sub-ppb NO2 detection

Herein, high performance of sub-ppb NO2 sensors were fabricated based on Ag nanoparticles (NPs) decorated on hierarchical In2O3 nanospheres assembled by several nanocubes subunit via a facile hydrothermal route and the subsequent decoration process. The morphology evolution of the nanospheres is investigated, which revealed that the nanocubes of the nanospheres shared the same surface and self-assembled together according to the oriented attachment mechanism. When performing as sensors, such nanostructures possessed relatively good sensitivity to NO2. With respect to the decoration of Ag NPs, the sensing performances can be further remarkably promoted on account of the catalyst activation and spill-over effect.

Highly sensitive detection of acetone using mesoporous In2O3 nanospheres decorated with Au nanoparticles

Surface modification with noble metal is considered as an effective strategy to enhance sensing performance of metal oxide-based gas sensors. In this work, mesoporous In2O3 nanospheres decorated with gold nanoparticles (Au NPs) have been successfully synthesized by a two-step approach including a facile hydrothermal reaction and subsequent in situ reducing process. Various techniques were employed for the characterization of the structure and morphology of as-obtained Au/In2O3 nanocomposites. The results reveal that Au NPs with average diameters of 3–5nm are uniformly deposited on the surface of mesoporous In2O3 nanospheres with a size range of 100–200nm, specific surface area of 40.3m2/g, and average pore size of 5nm. Importantly, the mesoporous structure, large specific surface area, and catalytic effect of Au NPs endow the Au/In2O3 nanocomposites with highly sensitive performance for acetone detection. The response value to 10ppm acetone is about 53.08 at an operating temperature of 320°C, and the response and recovery time are 4 and 9s, respectively. The probable enhancing mechanism of as-prepared Au/In2O3 nanocomposites is discussed as well. It is expected that Au NPs-decorated mesoporous In2O3 nanosphere with excellent sensing performance is a promising functional material to actual application in monitoring and detecting acetone.

Rational Design of ZnFe2O4/In2O3 Nanoheterostructures: Efficient Photocatalyst for Gaseous 1,2-Dichlorobenzene Degradation and Mechanistic Insight

Novel ZnFe2O4/In2O3 hybrid nanoheterostructures with enhanced visible-light catalytic performance were fabricated by assembling ZnFe2O4 nanoparticles on the surface of monodispersed In2O3 nanospheres, and their photocatalytic performances were evaluated via the degradation of gaseous 1,2-dichlorobenzene (o-DCB). The catalytic activity of the resulting heterostructures for degradation of o-DCB was higher than that of either pure In2O3 or ZnFe2O4. The enhanced activity was mainly ascribed to the enhanced visible-light harvesting ability, efficient spatial separation, and prolonged lifetimes of photogenerated charges. Meanwhile, the main reaction intermediates including o-benzoquinone type species, phenolate species, formates, acetates, and maleates were verified with in situ FTIR spectroscopy. Additionally, a tentative catalytic reaction mechanism and the generation pathway of •OH over the ZnFe2O4/In2O3 nanoheterostructures were postulated. The present work provides some significative information for the er...

Facile synthesis of In2O3 nanospheres with excellent sensitivity to trace explosive nitro-compounds

In2O3 nanospheres with excellent sensing ability to explosive nitro-compounds have been successfully synthesized via a two-step method including a mild solvothermal process and calcination at elevated temperature in air. The as-synthesized In2O3 nanospheres are of 200–300nm in diameter and are composed of small nanoparticles with a size of around 5nm. The structure, morphology and thermal stability are investigated by XRD, SEM, TEM, HRTEM, TG and XPS. At 140°C, the responses of this sensor toward 100ppm nitromethane, nitroethane and nitropropane are 163, 220 and 375, respectively. And what’s more, the sensor also exhibits short response time of less than 1s, good long-term stability, and low detection limits. The good sensing performance should be attributed to the strong electron-withdrawing effect of nitro group and low working temperature.

Monodispersed In2O3 mesoporous nanospheres: One-step facile synthesis and the improved gas-sensing performance

Mesoporous In2O3 nanospheres were successfully synthesized by a simple solvothermal route, which was performed without the assistance of any additives or templates. The obtained mesoporous In2O3 nanospheres show high monodispersity with average size about 90nm and pore size about 2–4nm. The optical absorption property of the In2O3 mesoporous spheres was investigated by UV–vis spectroscopy, which indicates that the In2O3 mesoporous spheres are semiconducting with a direct band gap of 3.1eV. The gas sensing performance of the as-prepared In2O3 mesoporous nanospheres was investigated towards a series of typical organic solvents and fuels. For 100ppm of butanol and ethanol, the mesoporous In2O3 demonstrates sensing responses of 59.6 and 29.6, respectively. These values are much higher than those of the reported In2O3-based gas sensors and the In2O3 powder sample with similar size, indicating the highly enhanced gas sensing performance of In2O3 mesoporous nanospheres. The obtained In2O3 mesoporous nanospheres appear to be a promising sensing material for environmental detection application and would also find applications in catalyst, electrode, or related fields.

Enhanced methanol gas-sensing performance of Ce-doped In2O3 porous nanospheres prepared by hydrothermal method

In this work, novel Ce-doped In2O3 porous nanospheres have been prepared by calcining precursors obtained via a facile template-free hydrothermal method. The morphology and structure of the as-prepared samples were characterized by X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). FESEM and TEM images showed that as-prepared In2O3 samples were uniform and well-dispersed nanospheres with size of 200–300nm, which were composed of numerous small nanocrystallites. XRD, ICP, and XPS spectroscopy were used to identify the products structure and the peak shifts in spectroscopies confirmed that the Ce element was doped in cubic In2O3. Compared with pure In2O3 samples, Ce-doped In2O3 porous nanospheres showed excellent sensing performance toward methanol at the operating temperature of 320°C and had a response of about 35.2–100ppm methanol, which was much higher than that of the sensor based on pure In2O3 nanospheres. In addition, Ce-doped In2O3 porous nanospheres exhibited good selectivity and long-term stability.

Controlled Synthesis of Monodispersed Sub‐50 nm Nanoporous In2O3 Spheres and Their Photoelectrochemical Performance

AbstractUniform nanoporous In2O3 nanospheres with high surface areas were synthesized through a simple solvothermal route with ethylenediamine (en) as the solvent. The prepared In2O3 nanospheres with diameters about 50 nm are composed of many nanoparticles with average sizes of ca. 5 nm. The unique nanospheres inherit both the large surface areas of the nanoparticles and the high crystallinity of bulky materials. The introduction of water or some other solvents into the reaction solution results in the formation of InOOH and In(OH)3 particles indicating that en is indispensable for synthesis of In2O3 with a nanoporous nanosphere structure. UV/Vis spectroscopy reveals that the band‐gap of synthesized In2O3 nanospheres is about 2.95 eV, mostly close to that of the single‐crystalline bcc‐In2O3. The PL spectrum of the In2O3 nanospheres shows two emission peaks located at 470 nm and 483 nm. The photocurrent of the prepared In2O3 electrodes by electrophoretic deposition strongly depends on the calcination temperature. The highest photocurrent density up to 1.9 mA cm–2 at 0.65 V (vs. Ag/AgCl) in 0.1 M Na2SO4 aqueous solution was recorded in the sample annealed at 550 °C. The high photocatalytic activity of the In2O3 nanospheres can be attributed to the high surface area, and the large number of nanopores in the In2O3 nanospheres.

Structural and Acetone Sensing Properties of La-Doped Porous In<sub>2</sub>O<sub>3</sub> Nanospheres by Hydrothermal Synthesis

The La-doped porous In2O3 nanospheres were prepared by a simple hydrothermal method, and La3+ accounted for 3 mol% of the In3+. The La exists and has been doped in the lattice of In2O3 characterized respectively by the means of energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), the morphology of the samples with uniform nanospheres observed by field-emission scanning electron microscopy (FESEM). Moreover, the sensor exhibits higher response properties compared with pure porous In2O3 nanospheres towards different acetone concentration at operating temperature 300 °C. The response and recovery times is about 13 s and 8 s to 50 ppm acetone.

Hydrothermal synthesis of porous In2O3 nanospheres with superior ethanol sensing properties

Porous In2O3 nanospheres were synthesized by calcining the precipitates prepared through a facile one-step hydrothermal synthesis method. Techniques of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), and N2 adsorption–desorption analyses were used to characterize the structure and morphology of the products. The as-synthesized porous In2O3 nanospheres were composed of numerous tiny In2O3 nanoparticles and possess good size uniformity and large specific surface area. On the basis of experimental results, a possible mechanism for the formation of porous In2O3 nanospheres was speculated. Moreover, gas sensing investigation showed that the sensor based on porous In2O3 nanospheres exhibited higher response to ethanol gas compared with that of commercial bulk In2O3 particles. The enhancement in gas sensing properties was attributed to their unique structure, large surface areas, and more surface active sites.

Phase-controlled synthesis of monodispersed porous In2O3 nanospheres via an organic acid-assisted hydrothermal process

Phase-pure porous nanospheres, both In(OH)3 and InOOH, have been prepared through a facile hydrothermal method using different organic acids as the assistant agents. The organic acids play an important role in the phase change, and the phase composition of the precursors could be deliberately controlled by adjusting the organic acid (citric acid or tartaric acid). Cubic and hexagonal In2O3 monodispersed nanospheres with porosity can be obtained from In(OH)3 and InOOH, respectively, while size and morphology can be maintained to a certain extent. The as-synthesized porous In2O3 nanospheres are composed of numerous small nanocrystallites and possess good size uniformity. Influencing factors such as the reaction time and the type and amount of organic acids were systematically investigated. A possible ethylenediamine or tartaric acid coordinated mechanism of the phase-control synthesis of In2O3 was proposed based on the experimental results. Furthermore, the potentialities of the porous In2O3 nanospheres were also studied by room-temperature photoluminescence (PL) spectroscopy.

Template synthesis, organic gas-sensing and optical properties of hollow and porousIn2O3 nanospheres

Hollow and porous In2O3 nanospheres have been prepared by the hydrolysis ofInCl3 using carbonaceous spheres as templates in combination with calcination.Based on the observation of scanning electronic microscopy (SEM) andtransmission electron microscopy (TEM), it has been revealed that the as-preparedIn2O3 nanospheres have a uniform diameter of around 200 nm and hollow structures with thin shells of about30 nm consisting of numerous nanocrystals and nanopores. Owing to the hollow and porous structures,In2O3 nanospheres possessing more active surface area exhibit a good responseand reversibility to some organic gases such as methanol, alcohol, acetoneand ethyl ether. In addition, the response mechanism of hollow and porousIn2O3 nanospheres to organic gases has been proposed. Furthermore, these preparedIn2O3 spheres showed a UV–visible absorption peak centered at around 309 nm, and theirphotoluminescence spectra have also been investigated.