Sb-doped SnO2 Nanoparticles Research Articles

Ozone-Assisted Hydrothermal Synthesis Method of Sb-Doped SnO2 Conductive Nanoparticles for Carbon-Free Oxygen-Reduction-Reaction Catalysts of Proton-Exchange-Membrane Hydrogen Fuel Cells

Proton-exchange-membrane hydrogen fuel cells (PEMFCs) are an important energy device for achieving a sustainable hydrogen society. Carbon-based catalysts used in PEMFCs’ cathode can degrade significantly during operation-voltage shifts due to the carbon deterioration. The longer lifetime of the system is necessary for the further wide commercialization of PEMFCs. Therefore, carbon-free catalysts are required for PEMFCs. In this study, highly crystallized conducting Sb-doped SnO2 (Sb-SnO2) nanoparticles (smaller than 7 nm in size) were synthesized using an ozone-assisted hydrothermal synthesis. Pt nanoparticles were loaded on Sb-SnO2 supporting particles by polyol method to be “Pt/Sb-SnO2 catalyst”. The Pt/Sb-SnO2 catalyst showed a high oxygen reduction reaction (ORR) mass activity (178.3 A g-Pt−1 @ 0.9 V), compared to Pt/C (149.3 A g-Pt−1 @ 0.9 V). In addition, the retention ratio from the initial value of electrochemical surface area (ECSA) during 100,000-voltage cycles tests between 1.0 V and 1.5 V, Pt/SnO2 and Pt/Sb-SnO2 catalyst exhibited higher stability (90% and 80%), respectively, than that of Pt/C catalyst (47%). Therefore, the SnO2 and Sb-SnO2 nanoparticles synthesized using this new ozone-assisted hydrothermal method are promising as carbon-free catalyst supports for PEMFCs.

Structural and optical characteristics of Sb doped SnO2 nanoparticles and their boosted photocatalytic activity under visible light irradiation

Recent developments in nanomaterials have shown that multifunctionality in materials can be best achieved by using doping techniques. In this work, a simple sol-gel approach is employed to successfully prepare Sb-doped SnO2 nanoparticles. XRD, FESEM, UV–Vis spectra, Pl, and XPS were used to observe the imprints of Sb doping on the structural and optical features of SnO2 and the photocatalytic capabilities of prepared nanoparticles. The prepared SnO2 has a tetragonal rutile-type structure, and the crystallite size was found to decrease with an increase in Sb doping from ATO-0 to ATO-4 and then increase with further increment in Sb doping for ATO-6. Band gap energies of 3.5 eV, 3.67 eV, 3.71 eV, and 3.73 eV were observed for ATO-0, ATO-2, ATO-4, and ATO-6, respectively, using UV–Vis spectroscopy. Band gap changes, owing to Sb doping, in the prepared samples, which enhances the absorption in the visible light range. The inherent property of the sample to degrade the methylene orange solution was used to measure the higher photoactive response of the doped sample; this is ascribed to the enhanced efficiency with which photogenerated electron-hole pairs get separated. There is a pronounced effect on the photocatalytic activity of catalysts with antimony doping. Using a Sb–SnO2 catalyst, the photocatalytic degradation of methylene orange is studied in depth. The improved ability to catalyse a chemical reaction using light has been observed in materials that have been intentionally modified by the introduction of impurities or doping.

Effect of Cr/Sb doping and annealing on nonlinear absorption coefficients of SnO2 /PMMA nanocomposite films

Cr and Sb doped SnO2 nanoparticles were synthesized by hydrothermal method. The structural measurements of as-grown nanoparticles exhibited that the incorporation of the 3% wt. Cr and Sb dopant into the SnO2 crystal structure led to increasing crystallite size but further doping (7% wt. and 10% wt.) caused to decreasing crystallite size. On the other hand, the annealing processes caused to increasing of the crystallite size. SnO2/PMMA, SnO2:Cr/PMMA and SnO2:Sb/PMMA nanocomposite films were deposited on fused silica substrate by using spin coating method. The as-deposited nanocomposite films have wide band gap energy and the band gap energies decreased after annealing process due to the increase of the particle sizes. Annealed nanocomposite films have strong transmittance in the ultraviolet and visible region. In order to investigate the effect of doping and annealing on nonlinear absorption properties of the films, open aperture Z-scan experiments were performed. To derive the transmission in open aperture Z-scan data, a theoretical model incorporating one photon, two photon, and free carrier absorptions and their saturations were considered. Nonlinear absorption coefficients and saturation intensity thresholds were extracted from the fitting of the experimental results. Nonlinear absorption coefficients and saturation intensity thresholds increased with increasing of the doping concentration because of the increasing of the defect states in the band gaps and decreased due to the decreasing of the defect state density with annealing. Strong optical limiting behavior observed for %10 Cr and %10 Sb doped SnO2 nanocomposite films.

Sb-doped SnO2 nanoparticle-modified carbon paper as a superior electrode for a vanadium redox flow battery

Herein, we proposed a facile strategy for preparing well-distributed Sb-doped SnO2 nanoparticles on carbon paper (CP) via electrodeposition and in-situ oxidation as bifunctional electrodes for vanadium redox flow batteries. SnO2 and Sb-doped SnO2 modified carbon paper (CP-SnO2 and CP-SnO2/Sb) was respectively obtained by electrodepositing metals (Sn and Sn/Sb) nanoparticles, followed by a conversion to metal oxides with in-situ oxidation. CP-SnO2 exhibited better electrochemical performance toward V3+/V2+ and VO2+/VO2+ redox reactions than CP. This is because SnO2 increases active sites and hydrophilicity, which accelerates electrochemical kinetic and mass transfer for vanadium redox reactions. CP-SnO2/Sb had better electrochemical activity than CP-SnO2, because smaller Sb-doped SnO2 nanoparticles more effectively disperse through carbon fibers, producing more active sites. Furthermore, Sb doping improved conductivity of SnO2. Briefly, CP-SnO2/Sb exhibited excellent hydrophilicity, abundant active sites, and good conductivity, resulting in superior electrochemical activity. We next employed CP-SnO2/Sb as bifunctional electrodes in cell. The cell using CP-SnO2/Sb had better cycling stability and more capacity retention during a 50-cycle charge–discharge test at 50 mA cm−2. CP-SnO2/Sb reduced the electrochemical polarization of cell at higher current density. Overall, the cell using CP-SnO2/Sb showed a 9% increase in energy efficiency compared to pristine cell (64.5%) at 150 mA cm−2.

In Situ Resistance Monitoring during Flame-Aerosol Deposition of Metal Oxide Gas Sensing Layers

Introduction Chemo-resistive sensors are highly promising for the detection of trace-level compounds in medical diagnostics[1] or indoor air monitoring[2]. In particular, gas sensors made by direct flame-aerosol synthesis are attractive due to their highly porous and crack-free sensing films[3]. They are composed of high-surface area nanoparticles with diverse composition tuned for ppb-level sensitivity and high selectivity towards key analytes such as Si-doped WO3 for acetone[1] or Ti-doped ZnO for isoprene[4]. Fabrication development has also led to the ability to process flame-made sensors by techniques compatible with standard silicon-wafer micromachining[5]. This enables the preparation of low power sensors that are attractive for portable handheld devices. So far, the development of such sensors has been focused mostly on material composition and, to a lesser extent, on film morphology and design. However, optimizing the latter could improve the sensor sensitivity as well as response and recovery times. Measuring the resistance during flame-deposition of nanostructured films in situ offers fabrication control by providing immediate feedback when an interconnected film is created[6]. This ultimately allows the fabrication of sensing films of minimal thickness and optimal resistance in a reproducible and economical manner. In situ resistance monitoring This work focuses on in situ monitoring the resistance of nanostructured films fabricated by direct deposition of flame-made Sb-doped SnO2 nanoparticles[6]. The sensing film morphology was tuned by a substrate-impinging particle flame, fed by a precursor solution containing varying metal ion concentrations. In situ resistance monitoring enabled control over final film resistance as well as direct insight into network formation and nanoparticle growth, necking and coalescence. The performance of these films as ethanol vapor sensors was assessed and related to their in situ resistance and nanoparticle film characteristics. Method Gas sensing nanoparticle films were prepared by direct deposition of flame-made Sb-doped (12 at%) SnO2 onto alumina substrates with interdigitated platinum electrodes. Deposition was carried-out for up to 6 min. Substrate preheating, film deposition and cooling to room temperature was closely monitored by the in situ resistance (Ri) between the interdigitated electrodes with a multimeter (Tektronix DMM4050). Nanoparticle sensing films were imaged by scanning electron microscopy (Hitachi S-4800 FE-SEM) after particle deposition for 2 min. Results and Conclusions Figure 1a shows the formation of Sb-doped SnO2 nanoparticles in a flame, followed by direct deposition onto the sensor substrate and in situ film resistance (Ri) read out. Figure 1b shows the in situ film resistance as a function of deposition duration using 1 (red squares), 10 (blue circles) or 100 (green triangles) mM FSP precursor solution concentrations (PSC). At low PSC (1 mM), the Ri remains at first (up to ca. 1 min) rather indifferent to nanoparticle deposition as it takes some time to build the interconnected particle bridges. But as deposition is prolonged (t >1.5 min), the Ri starts to drop. This clearly indicates the formation of an interconnected network of nanoparticles. Also quite notable is the strong oscillation of Ri by more than an order of magnitude during network formation. This stems from the constant formation (by deposition) and break-up of necked nanoparticles (by coalescence) on the substrate (i.e., repeatedly from lace-like to cauliflower-like structures) during flame-deposition. Increasing the PSC from 1 to 10 mM or 100 mM leads naturally to a higher generation rate of nanoparticles and, therefore, faster drop in resistance. This is confirmed by SEM imaging after 2 minute deposition time for 1, 10 and 100 mM (Figure 2 a-c). As expected, nanoparticles are assembled more densely at higher PSC. As a result, the film formation and morphology of Sb-doped SnO2 can be monitored during direct flame-deposition. This monitored Ri is correlated to its evolving particle size and necking, enabling the ability to optimize material quantity, fabrication time and the final film resistance. This leads to the ability to rapidly synthesize thin flame-made gas sensors with improved sensitivity and reduced response/recovery times.

Ultra-Tiny Sb-Doped SnO2 Nanoparticles as a Superior Catalyst for Vanadium Redox Reactions

Herein, ultra-tiny Sb-doped SnO2 nanoparticles were prepared using co-precipitation as superior catalyst for vanadium redox reactions. Different concentrations of Sb in range of 2%, 5%, and 10% were doped in lattice structure of SnO2. The size of nanoparticles decreased, as doping concentration increased. Sb doping also decreased the crystallinity of SnO2, producing structural defects. It is notable that Sb-doped SnO2 showed greatly improved conductivity. However, excessive Sb doping reduced conductivity of SnO2. Sb-doped SnO2 exhibited better electrocatalysis for V3+/V2+ and VO2+/VO2+ reactions. It benefits from Sb-doped SnO2 with smaller size, more structural defects, and higher conductivity, increasing active sites and electron transfer rate for vanadium redox reactions. SnO2/Sb-5% showed the best electrocatalysis. SnO2/Sb-5% was used to modify graphite felt, such that it had better electrochemical performance for vanadium redox reactions. A cell using SnO2/Sb-5% improved electrolyte usage and discharge capacity retention at 50 mA cm−2 for 50 cycles. SnO2/Sb-5% also efficiently reduced electrochemical polarization of cell. The cell using SnO2/Sb-5% had higher energy efficiency compared to pristine cell. At 150 mA cm−2, the energy efficiency of modified cell increased by 9.2% compared with pristine cell (57.3%). Therefore, Sb-doped SnO2 can be used as a promising catalyst for vanadium redox reactions.

Preparation and characterization of Sb-doped SnO2 (ATO) nanoparticles with NIR shielding by an oxidation coprecipitation hydrothermal method

ATO nanoparticles with different doping amounts of antimony were synthesized by an oxidation coprecipitation hydrothermal method. The obtained ATO nanoparticles were characterized by XRD, FTIR, HRTEM, EDS, XPS and UV-Vis-NIR Spectroscopy. The results show that ATO nanoparticles have been successfully prepared. The transmittance spectra of the sample films coated on the glasses in IR band wavelength demonstrates excellent NIR shielding performance, which means prepared ATO films could be used as thermal insulating coating on the surface of building glass.

Exceptional anodic performance of Sb-doped SnO2 nanoparticles on electrochemically exfoliated graphene for lithium-ion batteries

Metal oxides such as SnO2 are widely studied as anode materials for next-generation lithium-ion batteries because of their high theoretical capacities. However, the lithium storage capability of SnO2 is suppressed by its poor electrical conductivity and serious volume change during the charge and discharge processes. In this work, SnO2 nanoparticles are directly grown on the surface of electrochemically exfoliated graphene, followed by doping Sb into SnO2 nanoparticles. As a high quality of graphene, electrochemically exfoliated graphene possesses high electrical conductivity and strong mechanical strength, which is beneficial to the charge transfer from graphene to SnO2 nanoparticles. Moreover, the doping of Sb into SnO2 nanoparticles inhibits the agglomeration and growth of SnO2 nanoparticles, and further improves the electron conductivity of SnO2 by changing the electronic structure of SnO2. As a result, electrochemically exfoliated graphene-based SnO2 with Sb doping exhibits superior electrochemical performance including high reversible capacity, excellent cycling stability and remarkable rate capability. Modifying the electronic structure of metal oxides by doping with appropriate metals may provide an avenue to realize the demand of high-performance electrodes for secondary batteries.

Enhanced visible light photocatalytic activity for g-C3N4/SnO2:Sb composites induced by Sb doping

In this paper, g-C3N4/SnO2:Sb composite photocatalysts were fabricated by in situ loading Sb-doped SnO2 (SnO2:Sb) nanoparticles on graphitic carbon nitride (g-C3N4) nanosheets via a facile hydrothermal method. The synthesized g-C3N4/SnO2:Sb composites delivered enhanced visible light photocatalytic performance for degradation of rhodamine B in comparison with g-C3N4/SnO2 composites without doping Sb. Various techniques including XRD, SEM, TEM, FTIR, XPS, PL and electrochemical method were employed to demonstrate the successful fabrication of g-C3N4/SnO2:Sb composite and to investigate the enhanced mechanism of photocatalytic activity. The improvement of visible light absorption and the promotion of separation efficiency and interfacial transfer of photogenerated carriers induced by Sb doping were responsible for the enhancement of photocatalytic activity. This study provides a simple and convenient method to synthesize a visible light responsive catalyst with promising performance for the potential application in environmental protection.

Dopant-dependent crystallization and photothermal effect of Sb-doped SnO2 nanoparticles as stable theranostic nanoagents for tumor ablation.

Ideal theranostic nanoagents should be "all-in-one" type nanocrystals that have a single-semiconductor component and all-required properties (such as imaging and photothermal effects), but most semiconductor nanocrystals do not have these required properties. With SnO2 as a model of a typical wide-band semiconductor, we report the tuning from UV-responsive SnO2 to blue SnO2 nanocrystals with imaging ability and a Sb-doping-dependent photothermal effect. Sb-Doped SnO2 nanocrystals were prepared by heating SbCl3 and SnCl4 in benzyl alcohol solution through a facile solvothermal route. When the SbCl3/SnCl4 molar ratio increases from 0 to 0.2/1, the obtained samples exhibit an increased photothermal effect under the irradiation of a 1064 nm laser, accompanied by gradually decreased size and crystallinity. With a further increase of the molar ratio from 0.3/1.0 to 1.0/1.0, the resulting samples demonstrate the tetragonal SnO2 phase with amorphous-like compounds and they show no obvious enhancement of a photothermal effect. After a surface modification with biological molecules, the optimized Sb0.2-SnO2 nanocrystals demonstrated good stability and a high photothermal conversion efficiency of 48.3% as well as low cytotoxicity. When Sb0.2-SnO2 was injected into a tumor of mice, the tumor could be simultaneously detected by X-ray computed tomography (CT) and photoacoustic (PA) imaging, and then thermally ablated when exposed to a 1064 nm laser. Therefore, these nanocrystals can be used as "all-in-one" type nanoagents for imaging guided photothermal ablation of tumors under the irradiation of a laser in the second bio-transparent window.

A comparative investigation on humidity sensing and photocatalytic applications of Sb doped SnO2 by microwave combustion route

This work highlights the high sensitivity humidity sensor and photocatalytic activity of pure and Sb doped SnO2 nanoparticles by microwave combustion route. The role of Sb dopant on structural, morphological and optical properties were systematically investigated by powder X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Raman spectra, UV–Vis absorption spectra and Photoluminescence spectra analysis. PXRD and Raman results reveal that SnO2 is nanocrystalline with tetragonal structure. The structure of SnO2 does not change with Sb doping but the shape of the nanoparticles changes from spherical to needle like morphology by Sb doped SnO2, which is confirmed through FESEM micrographs. Tuning of band gap and enhanced absorption edge was found to be UV and PL spectra analysis. The Sb doped SnO2 sample showed high performance humidity sensing such as high sensitivity, fast response (40 s) and recovery time (35 s). The photocatalytic activities of the samples were evaluated by photocatalytic degradation of Methylene blue and Crystal violet and the results showed that Sb doped SnO2 could enhance photocatalytic activity compared to the undoped SnO2 nanoparticles. The most probable photocatalytic mechanism is also proposed in detail.

Sb-doped SnO2/graphene-CNT aerogels for high performance Li-ion and Na-ion battery anodes

SnO2 has been extensively explored as a potential anode material for both Li-ion (LIBs) and Na-ion batteries (SIBs). It possesses however an extremely poor electrical conductivity, making it difficult to be used as the standalone electrode. Herein, Sb-doped SnO2 (ATO) nanoparticles are in situ grown on N-doped graphene-CNT aerogels (N-GCAs) based on a facile hydrothermal self-assembly route for the first time. The ATO/N-GCA composite presents a highly porous structure along with an electrical conductivity enhanced by over two orders of magnitude through the in situ Sb doping. The composite electrode delivers an outstanding rate capability of 659mAhg−1 at 10Ag−1 with capacity retention of 73% after 1000 cycles at 1Ag−1 in LIBs. The same electrode also maintains 74% of its capacity after 500 cycles in SIBs, confirming a promising anode for both rechargeable batteries. We reveal distinct reaction kinetics and phase transition behaviors of ATO electrodes in different rechargeable batteries. The lithiation of ATO ensues consecutive conversion and alloying reactions while only the conversion reaction takes place during sodiation. Furthermore, the diffusion coefficient of Na+ ion in ATO is nine orders of magnitude lower than that of Li+ ions. The enhanced electrical conductivity of SnO2 by Sb doping dominates the capacity enhancements in LIBs whereas the mesoporous structure of hybrid aerogel plays a more important role in enhancing the Na+ ion storage performance. These new findings may offer insights into the relatively poor performance of SIBs and will help proper structural design of high performance bi-functional anodes for alkali metal ion batteries.

Electronically Conductive Sb-doped SnO2 Nanoparticles Coated LiNi0.8Co0.15Al0.05O2 Cathode Material with Enhanced Electrochemical Properties for Li-ion Batteries

The LiNi0.8Co0.15Al0.05O2 (NCA) cathode material is modified by electronically conductive antimony-doped tin oxide (ATO) nanoparticles via a facile wet chemical process. As observed by scanning and transmission electron microscopy, the ATO nanoparticles are homogeneously coated on the surface of NCA material. Thus-obtained ATO-coated NCA (ATO-NCA) material delivers a high discharge capacity of 145mAhg−1 at the current rate of 5C, which is significantly higher than that of pristine NCA material (135mAhg−1). Moreover, the capacity retention of ATO-NCA material is 91.70% after 200 cycles at the current rate of 1C and 60°C. In contrast, the pristine NCA only maintains 70.89% of its initial capacity after the same cycles. The substantially improved cyclability and rate capability are mainly attributed to the ATO coating layer, which can not only enhance the electron transport but also effectively restrain the side reactions between the NCA material and the electrolyte. More specifically, X-ray diffraction and photoelectron spectroscopy reveal that the ATO coating layer can restrain the Li+/Ni2+ disordering and the growth of SEI layer of NCA material, which are responsible for the improved cycling stability, especially at elevated temperatures.

Ultrafast Lithium Storage Using Antimony-Doped Tin Oxide Nanoparticles Sandwiched between Carbon Nanofibers and a Carbon Skin

Metal oxides as anode materials for Li-ion batteries (LIBs) are of significant interest to many potential technologies because of their high theoretical capacity value, low price, and environmentally friendly features. In spite of these considerable benefits and ongoing progress in the field, momentous challenges exist, related with structural disintegration due to volume expansion of electrode materials. This leads to rapid capacity decline and must be resolved in order to progress for realistic utilization of LIBs with ultrafast cycling stability. This article proposes a novel architecture of Sb-doped SnO2 nanoparticles sandwiched between carbon nanofiber and carbon skin (CNF/ATO/C) using electrospinning and hydrothermal methods. The CNF/ATO/C exhibits superb electrochemical behavior such as high specific capacity and outstanding cycling stability (705 mA h g-1 after 100 cycles), outstanding high-rate performance (411 mA h g-1 at 2000 mA g-1), and ultrafast cycling stability (347 mA h g-1 at 2000 mA g-1 after 100 cycles), which is high compared to any reported value using SnO2-based anode materials. Thus, this unique architecture furnishes profitable effects, including electroactive sites, structural stability, and electrical conductivity, which can potentially be realizes for ultrafast LIBs.

Efficient photocatalytic degradation of phenol in aqueous solution by SnO2:Sb nanoparticles

Photodegradation of phenol in the presence of tin dioxide (SnO2) nanoparticles under UV light irradiation is known to be an effective photocatalytic process. However, phenol degradation under solar light is less effective due to the large band gap of SnO2. In this study antimony (Sb) doped tin dioxide (SnO2) nanoparticles were prepared at a low temperature (80°C) by a sol–gel method and studied for its photocatalytic activity with phenol as a test contaminant. The catalytic degradation of phenol in aqueous media was studied using high performance liquid chromatography and total organic carbon measurements. The change in the concentration of phenol affects the pH of the solution due to the by-products formed during the photo-oxidation of phenol. The photoactivity of SnO2:Sb was found to be a maximum for 0.6wt.% Sb doped SnO2 nanoparticles with 10mgL−1 phenol in water. Within 2h of photodegradation, more than 95% of phenol could be removed under solar light irradiation.

Enhanced Near-IR Cutting Performance in the Mixture of Cs(x)WO3 and Sb:SnO2 Nanoparticles.

The Cs(x)WO3 nanoparticles were synthesized at 800 degrees C under a reducing ambient, and then milled up to nanoscale by a high-energy ball planetary miller. They showed a single phase, and a mean particle size of 80 nm. The Cs contents (x) in Cs(x)WO3 nanoparticles were optimized to be x = 0.32 to maximize the shielding performance around the wavelength of 1200 nm. To compensate still lower absorption above the wavelength of 1200 nm, they were mixed with Sb-doped SnO2 nanoparticles. Thus we achieved the visible transmittance of 70% at 540 nm and the near-infrared absorption of 80% at 1000 nm and 94% at 1400 nm.

Preparation of Sb Doped Nano SnO2/Porous Ti Electrode and Its Degradation of Methylene Orange

Sb doped nano SnO2 coating electrode was prepared on the porous Ti by a simple thermal decomposition method and then its electrochemical property for degradation of methylene orange was also investigated. SEM and XRD measurements results show that an integrative and crackless coating layer on porous Ti substrate can be obtained. The crackless coating surface is composed of Sb doped SnO2 nanoparticles with a size range from 80 nm indicates to 230 nm. HRTEM test suggests that these SnO2 nanoparticles consist of coating grains with 5∼6 nm. Intensified life time test indicates that SnO2/porous Ti electrode has a longer service life time than the coatings on dense titanium plate. Moreover, the as-prepared Sb doped SnO2/porous Ti electrode can degrade the methylene orange with 100 mg/L concentration into that with 8 mg/L, which reveals that the electrode has a strong electrochemical ability to degrade organic pollutants. A simple surface treatment of porous Ti for organic pollutants degradation was presented in the paper, showing its great application potential in the area of pollutants degradation.

Optical Property of Sb-Doped SnO<sub>2</sub> Nanoparticle Thin Films by Sparking Process

Undoped and Sb doped SnO2 nanoparticle thin films were synthesized by sparking process. The nanoparticles were continuously deposited onto the substrate by varying the number of sparking cycles ranging from 10-30 and the deposited film were subsequently annealed at 500 °C in tube furnace under air atmosphere for 1 h. The effect of Sb doped SnO2 nanoparticles thin film on their structure and optical characteristics were investigated. The optical properties of the nanoparticles thin films have been studied from transmission spectra. An average transmittance of the thin films decrease from 70% to 50% when the doping level increased from 0 to 7 %Sb doped SnO2. Opitical band gap energy of thin films were found to vary in range of 3.85-3.89 eV which the energy band gap decrease with the increasing Sb doping concentration. From the experimental data, the reduction of optical transmittance spectra in the antimony doped SnO2 thin films make it suitable for generation of window layer coating and prevent unwanted absorption in UV range.

Sb-Doped SnO2 Nanoparticles Synthesized by Sonochemical-Assisted Precipitation Process.

Sb-doped SnO2 nanopowders were synthesized by sonochemical-assisted precipitation process using stannic chloride pentahydrate (SnCl4.5H2O) and antimony chloride (SbC3) as starting precursors. Effect of sonication and Sb doping concentrations on physical structures and electrical properties of Sb-doped SnO2 nanoparticles were investigated by X-ray diffraction, transmission electron microscope, X-ray photoelectron spectroscopy, Raman spectroscopy and two-point probe method. The results indicated that the good dispersion with less agglomeration of particles in SnO2 phase can be obtained by single step sonochemical-assisted process. Moreover, XRD results indicated that the crystallinity of Sb-doped SnO2 nanopowders deteriorated with increasing Sb content, suggesting that Sb dopant significantly prevent SnO2 crystallite growth. The XPS spectra of Sb-doped SnO2 obviously confirmed the existence of Sb ion incorporated into SnO2 matrix. These results revealed that incorporation of Sb ions into SnO2 lattice with specific concentration has significant influence on formation and crystallization and can dramatically enhance the conductivity of tin oxide.

Sb-Doped SnO2 Supported Platinum Catalyst with High Stability for Proton Exchange Membrane Fuel Cells

Sb-doped SnO2 (ATO) nanoparticles were prepared and used as highly stable catalyst support for proton exchange membrane fuel cells. The results of the electrochemical analysis reveal that Pt/ATO has a comparable oxygen reduction reaction (ORR) activity to commercial Pt/C, and demonstrates significantly improved durability than Pt/C. After 800 cycles between 0.6 and 1.2 V vs. NHE, the ORR mass activity of Pt/ATO dropped by 35.1%, which was much lower than that of Pt/C (78.4%). The enhanced electrochemical stability of Pt/ATO is attributed to the high stability of ATO support and the strong interaction between Pt and ATO.