Antimony-doped Tin Dioxide Research Articles

Precisely regulated crystalline phase of TiO2@composite G doped with Al3+: For the preparation of highly conductive, corrosion resistant conductive coatings

The development of conductive materials is crucial to the upgrading of modern science and technology industries. In recent years, the research on conductive materials synthesized based on TiO2 has mainly focused on improving the conductivity and stability of the materials. And this study, based on the high conductivity of the material, innovatively proposes a method to precisely regulate the crystal phase and morphology of TiO2 by CH3COOH and temperature together. Meanwhile, the heterostructure was successfully built by doping Al3+ into the TiO2 lattice, and a new conductive pathway (Al-O-C) was constructed. Finally, the composite G was prepared as an Al3+-doped TiO2 composite G (Al-T/G) functional material, and it was verified by first-principles calculations (DFT). The experimental results show that the Al-T/G material not only has the low surface resistance and high whiteness of TiO2, but also is endowed with more excellent resistivity (0.203 Ω·cm) and protection efficiency (92.45 %). Meanwhile, compared with the conventional antimony-doped tin dioxide (ATO) conductive materials, the Al-T/G functional materials prepared in this paper are basically harmless to the environment in the experimental process while ensuring high conductivity. Most importantly, this paper explores the bonding mechanism of Al3+-doped TiO2 conductive materials, which provides new insights and ideas in the field of dopant-modified TiO2 conductive materials.

First Principles Study of Europium doped Gallium Nitride in Wurzite Structure

In the present work, we have successfully deposited Sb antimony doped tin dioxide (SnO2) thin films with Several advantages over well known LCD's including increased brightness and viewing angle. We are currently investigating Eu doped GaN as a potential red phosphor for TEFL display applications. Eu doped GaN films were grown by solid source molecular beam epitaxy on Si (111) substates. The material was optically characterized through temperature dependent emission spectroscopy using a He-Cd laser at 325 nm for above band gap excitation. A strong red emission was obtained at 622 nm, which corresponds to an Eu3+ inner 4f-shell transition from the 5D 0 to 7F2 state. Therefore, the observed thermal quenching of red Eu emission is assigned to a strongly temperature dependent pumping process.

Morphological Characterization of Sb-Doped SnO2 Thin Films Developed by Spray Pyrolysis

In the present work, we have successfully deposited Sb antimony doped tin dioxide (SnO2) thin films with different concentrations (0 at%, 1 at%, 3 at% and 5 at%) from a stannous (II) chloride dihydrate solution (SnCl2.2H2O), by the pyrolysis chemical spray deposition technique on ordinary microscope glass substrates preheated to a fixed temperature of 350 °C. After deposition, the films were annealed at temperatures 400 °C for 4h. The aim of this work is on the one hand to study the morphological properties of pure and doped tin dioxide thin films and to determine the different morphological parameters such as: the roughness Ra, Rq and on the other hand to study the effect of Sb doping on the morphological properties of SnO2 thin films. To achieve this purpose, the thickness of all the films was estimated by profilometer with standard scan type. The morphology of the films was examined by atomic force microscope (AFM) in contact mode at room temperature to visualize the surface of our samples (the structure, size and morphology of crystallites ... etc). The 2D and 3D AFM images confirm the formation of nanostructures on the surface, with shapes and dimensions influenced by the amount of antimony doping. All the samples show a polycrystalline morphology, and the grain size progressively decreases with the increase of the Sb concentration (1% and 3%). On the other hand, for high antimony doping (5% Sb) the grains are larger than those observed at 3% doping. The root mean square (RMS) surface roughness values for samples with Sb concentrations (5%) were found to be 8.334 nm.

Optoelectronic properties of fluorine and antimony-doped tin dioxide nanoparticles

Nano-sized tin dioxide SnO2 (TO) has garnered great potential for use in optoelectronic applications, gas sensors, and solar cell technology thanks to its unique properties. These properties can be further enhanced by altering dopants and crystallinity. To achieve these aims, we successfully synthesized nanoparticles of fluorine (F) and antimony (Sb) doped tin dioxide by using a modified sol-gel method. The synthesis process involved supercritical drying of ethyl alcohol. The effect of doping on TO sample microstructure, optical and electrical properties was studied, which is crucial to understanding its potential applications. The X-ray diffraction pattern reveals that the nanoparticles crystallized in the tetragonal rutile structure with a size varying from 22 to 25 nm depending on element doping. The structural analysis was further proved by Raman spectroscopy and FTIR investigations. The optical band gap energy decreases upon the doping, as evidenced by the Eg values of 3.88, 3.87, and 3.72 eV corresponding to, FTO, and ATO respectively. This result proves that our compounds are good candidates for optoelectronic applications. Further, the electrical properties proved the semiconductor behavior for all the samples. Its conductivity is thermally activated, with a decrease in activation energy observed upon the addition of dopants. Moreover, the temperature dependence of the exponents's’of the (ac) conductivity proves that the conduction mechanism varies with dopants. The decrease of s values for undoped and FTO samples revealed a dominant correlated barrier hopping, while the increase of ‘s’ for ATO confirmed the tunneling hopping mechanism. Furthermore, the representation of real and imaginary parts of impedance has also been analyzed. Thus, the obtained results open exciting opportunities for using these samples in many fields that foster the combination of optical and electrical properties.

Investigation on Sb-doped SnO2 as an efficient sensor for the detection of formaldehyde

The applicability of antimony-doped tin dioxide (Sb-doped SnO2) as a very precise sensor for detecting formaldehyde (HCHO) gas is investigated in this study. The sol-gel method was used to prepare pure SnO2 and Sb-doped SnO2 nanostructures, which resulted in better structural and morphological properties. The prepared samples were analyzed using several characterization techniques, including X-ray diffractometer (XRD), field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS). A structural investigation indicated the presence of a tetragonal SnO2 phase with a clear preference for the (110) orientation. Furthermore, the crystallite size reduced as the quantity of Sb doping rose. According to FE-SEM analysis, both the undoped (SnO2) and Sb-doped SnO2 samples had polyhedral structures. FTIR analysis verified the presence of organic functional groups in the prepared powder samples. The optical band gap (Eg) values decreased with an increasing concentration of Sb doping in the SnO2 nanostructures. XPS was used to determine the chemical elements of the prepared powder samples. In the gas sensing study, those based on 8 wt% Sb-doped SnO2 (referred to as ATO-8) outperformed the others. At room temperature, the ATO-8 sample demonstrated stronger sensor response, faster response and recovery durations (98 s/74 s), and linear behavior. These enhancements can be attributable to an increase in adsorbed oxygen species caused by Sb doping, highlighting ATO-8's potential as a substance for detecting HCHO. This study emphasizes the potential of ATO-8 as a significant resource for practical use in the detection of HCHO, with benefits such as improved indoor air quality, increased industrial safety, and advancements in environmental monitoring.

Pomegranate-like ATO/SiO2 microspheres for efficient microwave absorption in wide temperature spectrum

High-performance microwave-absorbing materials (MAMs) should meet both impedance matching and attenuation performance. Commonly, it is hard to maintain excellent microwave absorption (MA) performance at an elevated temperature because the reliance on impedance matching and dielectric loss about temperature mutually restricts. In this work, the pomegranate-like antimony-doped tin dioxide (ATO)/ silica dioxide (SiO2) spheres were fabricated via a simple spray drying process. When the spheres were used as functional units and dispersed in the matrix, the corresponding composites exhibit an outstanding anti-reflection effect on microwaves. Moreover, the unique pomegranate-like structure of the ATO/SiO2 spheres provides both the effective local eddy current and abundant heterogeneous interface, which therefore contribute harvest enhanced dielectric relaxation and improved absorption performance when compared with that of the corresponding ATO/SiO2 composition. As a result, the maximum reflection loss of the ATO/SiO2 spheres composites can reach –47.8 dB at 9.7 GHz with a thickness of 1.8 mm, while the reflection loss could reach –47.3 dB at 573 K and the effective absorption bandwidth is 2.4 GHz. This work reveals the importance of local eddy current loss in optimizing the electromagnetic wave (EMW) absorption performance and impedance matching, providing novel guidance on designing advanced high-temperature MAMs.

Antimony-doped tin dioxide ceramics used as standalone membrane electrodes in electrofiltration reactors enhance the oxidation of organic micropollutants

In the present work, microporous ceramics made of antimony-doped tin dioxide produced using a facile synthesis procedure were evaluated during the degradation of norfloxacin in a novel electrofiltration process. The antimony-doped tin dioxide ceramics were used as standalone electrodes accomplishing a dual function: as anodes and microfiltration membranes. The simultaneous generation of hydroxyl radicals and permeation of the electrolyte through the ceramic electrodes favors the effective utilization of their high active area in the degradation of organic compounds. The progress of the electrofiltration process was compared with that of a conventional flow electrolysis reactor using the ceramic electrodes and boron-doped diamond. By changing from a conventional flow reactor to an electrofiltration configuration, the effective utilization of the generated hydroxyl radicals is evidenced by the delayed transition from electrochemical-to mass transfer-controlled degradation rates. Evaluation of intermediate and by-product concentrations confirms the formation of acetate ions as a prior stage in the mineralization pathway using both types of electrodes. After 4 h of electrolysis, norfloxacin degradation rates of 98.3% and mineralization degrees of 82% were attained using the antimony-doped tin dioxide anodes at the highest permeate flow of 60 mL min −1 , approaching the outstanding performance of commercial boron-doped diamond electrodes. - Standalone Sb-doped SnO2 electrodes oxidize organic micropollutants - Microporous Sb-doped SnO2 plays a dual role as a membrane and as an electrode - Electrofiltration improves the effective use of • OH radicals in NOR oxidation. - Electrofiltration increases removal and mineralization of NOR - NOR removal degrees close to those achieved with BDD are obtained.

Theoretical prediction of transport coefficients of antimony doped tin dioxide

Doped Tin (IV) Oxide has excellent potential in high-temperature thermoelectrics because of its large bandgap. It has been thoroughly experimentally studied for high-temperature thermoelectric application. Low electron mobility limits the thermoelectric performance of oxides. Understanding the temperature dependence of mobility help increase thermoelectric performance. This is rarely performed. In this work, we study antimony doped tin dioxide. Combining the calculated transport properties and the existing experimental results, we obtain other transport properties. Unlike in bulk materials, the grain boundary scattering competes against the acoustic phonon scattering. The grain size, temperature, and carrier concentration determine the mobility. The small grain, low carrier concentration, and high temperature are beneficial to the mobility. Antimony doping also causes the Fermi level into the conduction band as deep as 0.59 eV, making the large bandgap SnO2 metallic. Furthermore, the conductivity effective mass demonstrates the doping effect. These findings might help design new oxide thermoelectric materials by decrease the grain size.

Efficient removal of refractory organics in landfill leachate concentrates by electrocoagulation in tandem with simultaneous electro-oxidation and in-situ peroxone

Leachate concentrates, an effluent produced from nanofiltration and/or reverse osmosis, contains a high amount of salts and dissolved organics especially refractory organics. Thus, the treatment of leachate concentrates would consume high energy or a large amount of chemicals. The present study is to develop an effective treatment method by using coupled electrochemical methods with the least possible energy consumption. The leachate concentrates was pretreated by electrocoagulation (EC), with aluminum or iron electrodes as anodes, to decrease the dissolved organic content. EC with Al electrode was found to be more efficient by consuming 1.25 kWh/m3 energy to remove 70% of total organic carbon (TOC). EC effluent was further subjected to a novel simultaneous electro-oxidation and in-situ peroxone process, which used a Ti-based nickel and antimony doped tin dioxide (NATO) as anode and a carbon nanotube coated carbon-polytetrafluoroethylene (CNT-C/PTFE) as cathode for oxygen reduction reaction (ORR). Compared with a traditional EO with cathode for hydrogen evolution reaction (HER-EO), ORR-EO obtained higher efficiency and an energy consumption of 26.25 kWh/m3, which was much lower than 35.5 kWh/m3 for HER-EO. Results showed that after ORR-EO, a final TOC of 57.3 mg/L was obtained. Thus, EC in tandem with ORR-EO process has an excellent capability and economic merit in the field of treating leachate concentrates.

Spray-grown highly oriented antimony-doped tin dioxide transparent conducting films

Undoped and Sb-doped tin dioxide films of varying thickness with a remarkable crystallographic orientation in the [200] direction were grown by spray-pyrolysis from tin(II) chloride solutions. Films grown on silica-coated glass substrates were completely crystalline and showed a higher degree of orientation with respect to films that were grown on uncoated glass. The presence of the silica barrier was seen to have increased the degree of orientation and to have enhanced the resulting electrical properties. Transmission electron microscopy revealed that the silica layer may have played the crucial role of a nucleation layer. Moreover, the developed microstructures were correlated with the optical and electrical behaviour of the films. Dense conducting films with thicknesses between 280–450 nm and visible transmittances of 80-70 % showed resistivities of about 10−3 Ωcm.

Atomic Layer Deposition (ALD) of Pt on Sb-SnO2 Nanoparticles Produces Ultra-Stable, Active Catalysts for PEMFC Application

Mixed-metal oxides (MMOs) are a promising class of oxidatively stable supports for proton exchange membrane fuel cell (PEMFC) catalysts.1-5 Further, some Pt/MMO catalysts exhibit strong-metal-support interactions (SMSI) that enable them to exceed the activity of Pt/C.1, 6 A significant remaining challenge with Pt/MMO systems is the relatively low surface area and porosity that limits Pt nanoparticle dispersion on the support surface. Herein we have synthesized a highly conductive (6.2 S/cm) and stable antimony doped tin dioxide (ATO) support by a xerogel method. Pt clusters with minimal size distribution were well-dispersed over ATO using atomic layer deposition (ALD) technique. The performance of ALD-Pt/ATO was compared with Pt/ATO synthesized using other deposition methods. ALD-Pt/ATO exhibited significantly higher ECSA (74 m2/g) and oxygen reduction reaction (ORR) catalytic activity (102 mA/mgPt at 0.9 V vs. RHE) compared to Pt/ATO synthesized using ethylene glycol (ECSA=41 m2·gPt -1, mass activity=55 mA/mgPt at 0.9 V vs. RHE) and formic acid reduction methods (ECSA=38 m2·gPt -1, mass activity=48 mA/mgPt at 0.9 V vs. RHE). Characterizing with TEM and XAS of the Pt/ATO catalysts using shows broader Pt particle size distributions for catalysts prepared using wet chemical methods. These catalysts exhibited the added disadvantage of chemical degradation of the support during Pt deposition as verified using XAS. Given the near-ideal Pt particle size distribution of the ALD-Pt/ATO, particle size growth and loss of ECSA was found to be minimal over the course of accelerated start-stop cycling using the DOE/FCCJ protocol. After 10,000 accelerated start-stop cycles, ALD-Pt/ATO and other Pt/ATOs synthesized by wet chemical deposition were found to retain 100% of their initial ECSA compared to 57.6% retention for Pt/C. Further, following 10,000 cycles of accelerated load cycling test, ALD-Pt/ATO exhibited excellent stability, retaining 80% of initial ECSA, Pt/ATO synthesized by ethylene glycol and formic acid methods retained 70% and 69% of their initial ECSAs, respectively, while benchmark Pt/C exhibited only 55% of its initial ECSA. The stability of ALD-Pt/ATO can be attributed to the stability of the ATO support and narrow Pt particle size distribution.

Antimony-doped SnO2 nanoparticles-decorated TiO2 composite with enhanced electrical properties

Antimony-doped tin dioxide (ATO)-coated TiO2 (TiO2@ATO) composite was synthesized by a polymeric precursor method with lactic acid as the chelating agent. The structural and morphological characterizations of the as-fabricatied TiO2@ATO composite were investigated by XRD, FTIR, SEM, TEM and XPS. The resistivity was also examined by electrical resistance measurements. The theoretical calculations were introduced for elucidating the change of bandgap from the microscopic level. The results showed that the lowest resistivity of TiO2@ATO composite they could be achieved was 1.69 [Formula: see text]. TiO2@ATO composite possessed a core–shell structure with the ATO shell thickness of 13–16[Formula: see text]nm. The as-prepared ATO nanoparticles were in rutile phase and with 4.3–7.0[Formula: see text]nm in diameter (calcinated at 550∘C). The ATO grain growth during the calcination process could be viewed as consisting of two stages: the activation energies were calculated to be [Formula: see text][Formula: see text]kJ/mol and [Formula: see text][Formula: see text]kJ/mol, respectively.

High quality optoelectronic properties of Sb-doped SnO2 by spray pyrolysis with less solution

The antimony-doped (0–4 at %) tin dioxide thin films are deposited by spray pyrolysis method with a less volume of solution. The x-ray diffraction, atomic force microscopy, Raman spectroscopy, optical transmittances and electrical conductivity measurements are taken at room temperature. The structural, morphological, optical and electronic characteristics are determined using these measurements. The effect of antimony doping ratio on the optoelectronic properties of the samples is analyzed via figure of merit. In this study, the obtained best values for highest optical transmittance is 87.46 % at 650 nm wavelength, the lowest resistivity is 1.48 × 10–3 Ωcm and the highest figure of merit is 7.31 × 10–3 Ω−1 for 2 at % antimony-doped tin dioxide thin film.

Conductive TiO2 nanorods via surface coating by antimony doped tin dioxide

Abstract Titanium dioxide (TiO2) has been widely used as the white pigment in paintings and coatings. It is of significance to endow TiO2 powders with the high conductivity to extend its application. In this research, rutile TiO2 nanorods were prepared as the substrate material. Further the surface coating by antimony doped tin dioxide (Sb SnO2) shell layers was achieved to obtain conductive TiO2 nanorods. The morphology and structure of TiO2@Sb SnO2 nanorods was mainly focused on to obtain high conductivity by optimizing the calcination temperature. When the temperature was properly applied at nearly 500 °C, the calcination led to the fusion and attachment of Sb SnO2 crystalline regions on the surface of TiO2 nanorods, forming a continuous intact coating layer and thus getting lower volume electrical resistivity of the composite nanopowder. However, after calcination at 600 °C or higher temperature, the integrity of Sb SnO2 shell layers would be destroyed, resulting in the increased electrical resistivity. The conductive TiO2 nanorods obtained at the optimized reaction condition showed a very low resistivity of 52 ± 1.6 Ω cm, in contrast to 105 Ω cm of the pure TiO2. The conductive TiO2 nanorods would be excellent candidate for antistatic or electromagnetic shielding applications in coatings.

Electrochemical oxidation of gaseous benzene on a Sb-SnO2/foam Ti nano-coating electrode in all-solid cell

An all-solid cell with a solid polymer electrolyte was applied to electrochemical oxidation of low-concentration indoor gaseous aromatic pollution. Antimony-doped tin dioxide nanocoatings deposited on a titanium foam substrate (Ti/Sb-SnO2) with different Sb/Sn ratios (4.8–14.0 mol%) and loading weight of Sb-SnO2 (4.4–7.7 mg cm-2) were used as dimensionally stable anodes. Sn and Sb were homogeneously dispersed on the substrate, and a crack-free nanocoating was built when the loading of nanocoating was increased to 6.3 mg cm-2. The activity tests for oxidation of benzene showed that 40 ppm gaseous benzene was converted to CO2 with high selectivity (85%) at the low cell voltage of 2.0 V in this all-solid cell. The conversion of benzene was greatly increased from 30% to 100% upon increasing the Sb/Sn ratio of the nanocoating from 4.7 mol% to 14.0 mol%. With the increase of nanocoating loading (Sb/Sn = 14.0 mol%) from 6.3 to 7.7 mg cm-2, the conversion of 100 ppm benzene was increased from 70% to 100%. Cyclic voltammetry revealed that high Sb content in the oxide nanocoating increased the overpotential and current intensity of the oxygen evolution reaction. The large outer charge qo∗ related to the electroactive surface of the SS-7.7/Ti3 electrode was up to 305.3 mC cm−2, which were responsible for its excellent electrochemical performance in the benzene oxidation process. Our studies provide a potential method for removal of indoor VOCs at ambient temperature.

Ambipolar transport in tin dioxide thin film transistors promoted by PCBM fullerene

In this article, the effect of phenyl-C61-butyric acid methyl ester (PCBM) layer on the electrical performance of field-effect transistors (FETs) based on antimony-doped tin dioxide (Sb:SnO2) is reported. PCBM is a soluble variety of fullerene, n-type organic semiconductor, known to promote the p-type doping of semiconducting materials such as diamond and graphene, via charge transfer. Sb:SnO2 is an emerging low-cost transparent oxide semiconductor material that exhibits strong unipolar behavior (n-type). Ambipolar character in tin dioxide normally is not observed, however in this study we find that the deposition of PCBM on top of Sb:SnO2 promotes ambipolar behavior in Sb:SnO2 FETs. At negative gate bias (VG 0, and enhances the current in inversion mode. Besides, PCBM deposition also results in an increase of hole mobility at VG < 0.

Degradation of IrOx Nanoparticles Supported Onto Sb-Doped SnO2 Aerogel Monitored By Dynamic Electrochemical Impedance Spectroscopy and Identical-Location TEM

Supporting metal nanoparticles is a common approach in heterogeneous gas-phase catalysis to decrease the metal loading, prevent agglomeration and thus minimize the cost of a catalytic conversion. This approach proved particularly successful in proton-exchange membrane fuel cells (PEMFC) where the replacement of Pt-blacks (used in early PEMFCs) by carbon-supported Pt nanoparticles has significantly improved the Pt specific power density. Using the same material’s concepts in proton-exchange membrane water electrolysers (PEMWE) could minimize the noble metal loading especially at the anode where the oxygen evolution reaction (OER) takes place. However, high-surface area carbon supports are rapidly degraded in the operating conditions of a PEMWE anode (E > 1.6 V vs. the reversible hydrogen electrode, T = 80 °C) calling for alternative support materials. In this contribution, IrOx nanoparticles were synthesized using the polyol method and deposited onto antimony doped tin dioxide aerogel (ATO) or Vulcan XC-72 (as a reference), and tested as OER electrocatalysts. By combining classical electrochemical techniques, dynamic Electrochemical Impedance Spectroscopy (dEIS) and Identical-Location Transmission Electron Microscopy (IL-TEM), we gained some insights into the mechanisms leading to loss of OER activity. IL-TEM images (Figure 1) provide strong evidence that the activation step was detrimental to the ATO support while no major degradation was observed at higher voltages (OER region). Approximately 73 % of the initial activity was lost for IrOx/ Vulcan XC-72 after 4,000 potential cycles between 1.2 and 1.6 V vs. the reversible hydrogen electrode (RHE) compared to 16 % for IrOx/ATO. The polarization resistance measured in the OER region by dEIS remains roughly the same for IrOx/ATO while a large increase was observed for IrOx/Vulcan XC-72. Figure 1

Sb-Doped SnO2 Aerogels Based Catalysts for Proton Exchange Membrane Fuel Cells: Pt Deposition Routes, Electrocatalytic Activity and Durability

Tin dioxide is a promising catalyst support to improve the stability of proton-exchange membrane fuel cells (PEMFC) cathodes at high voltages. However, optimizing the catalytic activity for the oxygen reduction reaction (ORR) of tin dioxide based electrocatalyst still remains challenging. In this study, an antimony doped tin dioxide (ATO) aerogel featuring suitable physico-chemical properties for application at a PEMFC cathode was successfully synthetized. Two platinum nanoparticles deposition methods were tested and compared. One is a chemical reduction route (using ethylene glycol, EG), the other uses ultraviolet (UV) irradiation followed by different thermal post-treatments. Electrocatalysts structure and morphology were analyzed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) experiments. The highest ORR mass activity measured in liquid electrolyte at 25°C was obtained for Pt/ATO from EG method (32 A gPt−1 versus 27 A gPt−1 for a reference Pt/HSAC 40 wt%). Pt/ATO turned out to be more stable than Pt/HSAC during an accelerated stress test composed of 5,000 potential cycles between 1.0 and 1.5 V vs. RHE at 80°C.

Aqueous tetracycline degradation by coal-based carbon electrocatalytic filtration membrane: Effect of nano antimony-doped tin dioxide coating

In this work, a novel electrocatalytic filtration membrane with high degradation efficiency and low cost was fabricated by coating nano antimony-doped tin dioxide (Sb-SnO2) on a porous coal-based carbon membrane (CM) through sol-gel method. The nano Sb-SnO2 is homogeneously distributed on the CM surface and is firmly attached to the CM via C-O-Sn chemical bond. Due to the positive effect of nano Sb-SnO2 coating, the Sb-SnO2/CM possesses excellent electrocatalytic activity and shows a much better tetracycline (TC) degradation performance than CM. The TC removal rate of Sb-SnO2/CM could be achieved 96.5% after 6h operation while that of CM was only 72.8%. Degradation pathway of TC was also explored using HPLC-MS. Furthermore, the effective TC degradation is attributed to the synergistic effects of direct and indirect electrochemical oxidation. During the indirect oxidation process, OH radicals rather than O2- play the dominant role.

Sb or Nb Doped Tin Dioxide Aerogels Based PEFC Cathode

Catalyst supports for Polymer Electrolyte Fuel Cells (PEFC) are currently made up of carbon blacks. This material is however not thermodynamically stable in fuel cell operating conditions and loss of performance is observed with time, especially at the cathode side. To improve PEFC durability and make this technology a credible alternative to conventional power sources, carbon free cathodes were prepared. With a remarkable morphology, aerogels have already proven their ability to efficiently support catalysts for PEFC application [1, 2]. In this study doped tin dioxide aerogels are proposed as alternative support presumably stable in PEFC operating conditions.Antimony and niobium doped tin dioxide aerogels were synthetized using sol-gel route in acidic media from alkoxide precursors. These materials have shown particularly adapted physico-chemical properties [3]. Platinum catalyst supported on doped SnO2 aerogels was prepared by two methods. Method A was based on the impregnation of a platinum salt followed by a reduction under UV and a heat treatment in oxidative or reducing atmosphere. Method EG is a conventional polyol method using ethylene glycol. Electrocatalysts structures and morphologies were investigated by X-ray diffraction and transmission electron spectroscopy. Active Electrochemical Surface Areas (ECSA) and catalytic activities for oxygen reduction reaction (ORR) were measured on Rotating Disk Electrode (RDE). Method A leads to the formation of particularly well dispersed Pt nanoparticles on aerogel surface (Figure 1), whereas filament form was observed after the use of Method EG. Heat treatments have shown direct influence on Pt structure and crystallinity. Highest ECSA was recorded after method A (45 m². mgPt -1) while highest ORR mass activity was measured after method EG (40 mA. mgPt -1). This value is even higher than that of the chosen carbon based electrocatalyst reference, TEC10E40E, measured in the same conditions (23.4 mA. mgPt -1). Half-cell and MEA singlecell test measurements will also be presented to complete the characterization panel. The work presented here is funded by the European Union's Seventh Framework Program for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement n325239 (FCH-JU project Nano-CAT) and the French National Research Agency PROGELEC programme, (ANR-12-PRGE-007 project SURICAT). It was supported by Capenergies and Tenerrdis. Figure 1. TEM image of a Pt/Sb doped (10 at%) SnO2 aerogel from method A REFERENCES 1. M. Ouattara-Brigaudet, , S. Berthon-Fabry, C. Beauger, M. Chatenet, N. Job, M. Sennour, Influence of the carbon texture of platinum/carbon aerogel electrocatalysts on their behavior in a proton exchange membrane fuel cell cathode. International Journal of Hydrogen Energy37, 9742-9757 (2012). 2. M. Ouattara-Brigaudet, C. Beauger, S. Berthon-Fabry, P. Achard, Carbon Aerogels as Catalyst Supports and First Insights on Their Durability in Proton Exchange Membrane Fuel Cells. Fuel Cells11, 726-734 (2011). 3. G. Ozouf, C. beauger, Niobium- and antimony-doped tin dioxide aerogels as new catalyst supports for PEM fuel cells, Journal of Materials Science 51, 11, 5305-5320, DOI 10.1007/s10853-016-9833-7 (2016) Figure 1