Sb-doped SnO2 Research Articles

Enhancing electrocatalytic performance of Sb-doped SnO2 electrode by compositing nitrogen-doped graphene nanosheets

An efficient Ti/Sb-SnO2 electrode modified with nitrogen-doped graphene nanosheets (NGNS) was successfully fabricated by the sol–gel and dip coating method. Compared with Ti/Sb-SnO2 electrode, the NGNS-modified electrode possesses smaller unite crystalline volume (71.11Å3 vs. 71.32Å3), smaller electrical resistivity (13Ωm vs. 34Ωm), and lower charge transfer resistance (10.91Ω vs. 21.01Ω). The accelerated lifetime of Ti/Sb-SnO2-NGNS electrode is prolonged significantly, which is 4.45 times as long as that of Ti/Sb-SnO2 electrode. The results of X-ray photoelectron spectroscopy measurement and voltammetric charge analysis indicate that introducing NGNS into the active coating can increase more reaction active sites to enhance the electrocatalytic efficiency. The electrochemical dye decolorization analysis demonstrates that Ti/Sb-SnO2-NGNS presents efficient electrocatalytic performance for methylene blue and orange II decolorization. And its pseudo-first order kinetic rate constants for methylene blue and orange II decolorization are 36.6 and 44.0min−1, respectively, which are 6.0 and 7.1 times as efficient as those of Ti/Sb-SnO2, respectively. Considering the significant electrocatalytic activity and low resistivity of Ti/Sb-SnO2-NGNS electrode, the cost of wastewater treatment can be expected to be reduced obviously and the application prospect is broad.

Thermophysical properties of SnO2-based transparent conductive films: Effect of dopant species and structure compared with In2O3-, ZnO-, and TiO2-based films

Abstract

Preparation of MnO2 electrodes coated by Sb-doped SnO2 and their effect on electrochemical performance for supercapacitor

To enhance the specific capacity and cycling stability of manganese binoxide (MnO2) for supercapacitor, antimony (Sb) doped tin dioxide (SnO2) is coated on MnO2 through a sol-gel method to prepare MnO2 electrodes, enhancing the electrochemical performance of MnO2 electrode in sodium sulfate electrolytes. The structure and composition of SS-MnO2 electrode are characterized by using scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-Ray diffraction spectroscopy (XRD). The electrochemical performances are evaluated and researched by galvanostatic charge-discharge test, cyclic voltammogram (CV) and electrochemical impedance spectroscopy (EIS). The results show that SS-MnO2 electrodes hold porous structure, displaying superior cycling stability at large current work condition in charge-discharge tests and good capacity performance at high scanning rate in CV tests. The results of EIS show that SS-MnO2 electrodes have small internal resistance. Therefore, the electrochemical performances of MnO2 electrodes are enhanced effectively by Sb-doped SnO2 coating.

Synthesis and Corrosion Studies of Sb-Doped SnO2 (ATO) Support for Electrolysis Systems

This work deals with the corrosion resistance evaluation in acidic medium and electrochemical stability in a wide range (0 - 1.8 V vs ENH) for two different supports based on Sb doped SnO2 (ATO), one with low surface area (85 m2g-1) and the second one with a high surface area (216 m2g-1). Both materials were synthesized by sol - gel method and characterized by XRD, BET and HR-TEM. Both supports were compared with commercial Carbon Vulcan XC-72. The results show good chemical stability when the ATO and the modified-ATO are subjected to these conditions, whereas Vulcan carbon corrodes easily. This indicates that Sb-doped SnO2 is a good candidate for electrocatalyst supports for energy-conversion systems such as electrolysers and unified regenerative fuel cells.

Electrochemical Characterization of Sb-Doped SnO2 as Electrocatalyst Support for Electrochemical Energy Conversion Systems

Electrochemical energy conversion systems, mainly Unitized Regenerative Fuel Cells (URFC) and Solid Polymer Electrolyzer (SPE), are considered to have a promising future due to the generation of hydrogen in a clean and sustainable way. However, the design of oxygen electrodes is the main limiting factor for an efficient performance. In this matter, most of the studies have been focused in the development of efficient electrocatalyst for the oxygen reduction and water electrolysis reactions, and the use of electrocatalysts supports different from conventional carbon-based materials, which is susceptible of corrosion at the URFC and SPE operation conditions. Corrosion resistance supports, with improved surface area and conductivity, would reduce the electrocatalyst loading,the membrane electrode assembly degradation rate, and the global construction cost of the systems. The present work deals with the synthesis and electrochemical characterization of a Sb – doped SnO2 (ATO) for their potential use as electrocatalyst support in the oxygen electrode in electrochemical energy conversion systems. The synthesis of the support was performed by the sol –gel technique with a surface area modification with dodecylamine as surfactant followed by a thermal treatment. Electrochemical stability was evaluated by cyclic voltammetry (CV) with 250, 400 and 500 cycles in a wide range (0 – 2.0 V vs ENH), while the chronoamperometry (CA) was evaluated at high anodic potential (1.8 V vs ENH) in a continuous period of time of 5 h and 8 h. The results revealed that the Sb doped SnO2 support, present good electrical properties and electrochemical stability at a higher potential of 1.8 V vs. NHE in the presence of O2, as compared to other carbon-based and commercial sub-stoichiometric titanium oxide (Ebonex ®) supports.

Effect of Surface Morphology and Pore Structure on the Water Electrolysis, O2 Evolution Activity of Sb-Doped SnO2 Supported IrO2

Nanoparticle IrO2 supported on Antimony doped Tin Oxide (ATO) is a very active electrocatalyst for the oxygen evolution in polymer electrolyte water electrolysis. Using the modified polyol method [A. Marshal and et al. /Material Chemistry and Physics, 94 (2005) 226] nanoparticles of IrO2 were synthesized and deposited on commercial antimony doped tin oxide (ATO). This synthesis involves the reduction of a metal precursors (IrCl2) in ethylene glycol containing a suspension of ATO. Nanoparticle catalysts were characterized by cyclic voltammetry (CV) and steady state polarization analysis in 0.5 M H2SO4 solution. The CV voltammograms for IrO2/ATO catalyst showed clear broad peaks for oxidation and reduction of IrO2, with peaks at 0.72 V and 0.82 V respectively. The catalyst morphology, surface area and the pore structure were studied using BET nitrogen physisorption, mercury porosimetry, Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM). The BET surface area was found to be 59.4 m2/gr and the total porosity (interparticle and intraparticle porosity) of the catalyst was found to be 4.45 %. A narrow particle size distribution for the IrO2 phase in the range of 1 to 3 nm was determined by examining and analyzing the TEM images. X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were also done to provide information on the crystal structure and thermal properties. Polarization curves for membrane electrode assemblies (MEAs) fabricated using this catalyst will be presented. The importance of the pore structure in providing good catalytic activity and mass transport in the two-phase flow process will be discussed.

Improving the oxidation potential of Sb-doped SnO2 electrode by Zn/Sb co-doping

Inorganic oxides are recognized as attractive materials for developing anodes for wastewater treatment, potentially offering a cost effective solution for electro-oxidation. A key parameter in measuring the effectiveness of different anode materials is the oxygen over potential. In this paper, we study the role of Zn and Sb co-doping of SnO2 thin films to achieve enhanced oxidation potentials, suitable for use in wastewater treatment. The morphology, chemical, and electrochemical properties of the films were characterized, and as a result of an optimization study, suitable anode materials for wastewater treatment are identified.

Preparation and Properties of Eu, Sb Doped SnO<sub>2</sub> and Quartz Compound Conductive Powders

Eu, Sb doped SnO2 and quartz compound conductive powders are prepared by the coprecipitation method with SnCl4·5H2O, SbCl3, Eu2O3 and quartz powders as the raw materials. The crystal phase and structure of the prepared conductive particles are characterized by FTIR and XRD techniques respectively. The resistivity of the prepared conductive powders are measured with four-point measurement method. The resistivity of Eu, Sb doped SnO2 and quartz compound condu-ctive powders is 0.37 Ωcm. FTIR spectrum of Eu, Sb doped SnO2 and quartz compound conductive powders shows that there are the vibration peaks in 546.14 cm-1, 489.95 cm-1, 466.71 cm-1, 430.34 cm-1 and 418.92 cm-1 respectively, and have intense absorption in 4000 cm-1 ~ 1100 cm-1. Eu, Sb doped SnO2 conductive powders have a structure of tetragonal rutile. The complex doping is achieved well by coprecipitation method and is recognized as replacement doping or caulking doping. The composition of compound conductive powders are Eu, Sb doped SnO2 conductive powders and quartz powders.

Improvement of Thermoelectric Performance for Sb-Doped SnO2 Ceramics Material by Addition of Cu as Sintering Additive

The thermoelectric properties, such as the Seebeck coefficient value, S, electrical conductivity, σ, and thermal conductivity, κ, of Sb- and Cu-doped SnO2, that is, (Sn1−x−y Cu x Sb y )O2, were investigated in detail. The addition of a small amount of CuO significantly improved the relative density of the SnO2 ceramics. However, the relative density slightly decreased with the excessive addition of CuO (more than x = 0.03). The addition of Sb2O5 should cause an increase in the number of charge carriers, resulting in an increased σ value, and the addition of both CuO and Sb2O5 caused an increase in σ and |S| at high temperature. The improvement of the sintering performance caused the enhancement of the thermoelectric performance. As the temperature region measured in this study (293–1073 K), the maximum ZT value was 0.29 at 1073 K for (Sn0.985Cu0.005Sb0.01)O2.

Advanced Cathode Materials for Polymer Electrolyte Fuel Cells Based on Pt/ Metal Oxides: From Model Electrodes to Catalyst Systems

The development of stable catalyst systems for application at the cathode side of polymer electrolyte fuel cells (PEFCs) requires the substitution of the state-of-the-art carbon supports with materials showing high corrosion resistance in a strongly oxidizing environment. Metal oxides in their highest oxidation state can represent viable support materials for the next generation PEFC cathodes. In the present work a multilevel approach has been adopted to investigate the kinetics and the activity of Pt nanoparticles supported on SnO2-based metal oxides. Particularly, model electrodes made of SnO2 thin films supporting Pt nanoparticles, and porous catalyst systems made of Pt nanoparticles supported on Sb-doped SnO2 high surface area powders have been investigated. The present results indicate that SnO2-based supports do not modify the oxygen reduction reaction mechanism on the Pt nanoparticle surface, but rather lead to catalysts with enhanced specific activity compared to Pt/carbon systems. Different reasons for the enhancement in the specific activity are considered and discussed.

The Effect of SnO2-Sb Interlayer on the Physicochemical Properties of Electrodeposited Ti/PbO2 Electrodes

Lead dioxide (PbO2) coated titanium (Ti) anodes have been extensively investigated owing to its well-proven advantages such as low cost compared to those based on precious metals, good electrical conductivity that is comparable to metals, ease of preparation, high oxygen evolution potential and good stability in corrosive media [1]. However, traditional PbO2 deposited Ti electrodes suffer from poor adhesion problem, due to the formation of an insulating TiO2 between the coating and Ti substrate during anodic polarization in aqueous media. SnO2, as an interlayer, has been recently applied on Ti substrate to prepare PbO2anodes to improve the stability and electro-catalytic activity. The application of such doped interlayer is reported to have increased electrode’s chemical stability, enhanced electro-catalytic activity and greatly prolonged service life of the electrodes [2, 3,4].In the present work, we explored the electro-deposition process of PbO2 on the Ti substrate with a Sb-doped SnO2 interlayer, from a traditional acidic nitrate solution. By varying electro-deposition temperature, time and current density, we are able to synthesise PbO2 coatings with various morphologies (as can be seen in Figure 1.), microstructures and crystallite sizes. The surface morphology and phase structure were characterized by SEM and XRD. Voltammetric studies were performed using a conventional three-electrode cell system and a CHI604D (Chenhua, Shanghai) electrochemical workstation. It is found that an interlayer SnO2-Sb on Ti substrate can significantly promote the electro-deposition of PbO2 coatings. The preliminary results revealed that the electrochemical performance of deposited PbO2 largely depends on their morphologies and microstructures. The deposition temperature, deposition time and current density affect the PbO2 coatings in a synergic manner.It is our purpose to establish a correlation between electrolyte temperature, deposition time, current density and phase structure, morphological features on the Ti/SnO2-Sb substrate. This information may shed light on a further understanding of electro-crystallisation and also provide a perspective on further possible improvement of the electrochemical performance of PbO2coatings in terms of service lifetime and electro-catalytic activity. Keywords: Lead dioxide; Electro-deposition; Surface characterisation; SnO2 interlayer References [1] X. Li, D. Pletcher, F.C. Walsh, Chem. Soc. Rev., 40 (2011) 3879.[2] S. Song, L. Zhan, Z. He, L. Lin, J. Tu, Z. Zhang, J. Chen, L. Xu, J. Hazard. Mater., 175 (2010) 614.[3] Y. Wang, B. Gu, W. Xu, L. Lu, Rare Metal Mat. Eng., 36 (2007) 874.[4] H. An, Q. Li, D. Tao, H. Cui, X. Xu, L. Ding, L. Sun, J. Zhai, 258 (2011) 218.

Evaluation of the corrosion of Sb-doped SnO2 supports for electrolysis systems

The corrosion behaviour and electrochemical stability of two different electrocatalyst supports based on Sb-doped SnO2 (ATO) were evaluated in an acidic medium over a wide potential range (0–1.8 V vs. NHE). The results were compared with those from a commercial Vulcan carbon XC-72 (254 m2 g−1) support. ATO (85 m2 g−1) and modified-ATO (216 m2 g−1) were synthesized by the sol–gel method and were then characterized by XRD, BET and TEM. The modification of the ATO consisted of adding dodecylamine as a surfactant to generate a surface area similar to that of Vulcan carbon. The electrochemical characterization conditions were chosen to match the operating conditions of a proton exchange membrane fuel cell (PEMFC) and a solid polymer electrolyser (SPE), where the oxygen-evolution reaction takes place at a potential near 1.6 V with respect to normal hydrogen electrode (NHE). The results show good chemical stability when the ATO and the modified-ATO are subjected to these conditions, whereas Vulcan carbon corrodes easily. This indicates that Sb-doped SnO2 is a good candidate for electrocatalyst supports for energy-conversion systems such as electrolysers and unified regenerative fuel cells.

Electrochemical & microstructural investigations of magnetron sputtered nanostructured ATO thin films for application in Li-ion battery

Nanostructured Sb-doped SnO2 (ATO) thin films were prepared by radio frequency magnetron sputtering, and their electrochemical properties were evaluated versus Li metal in Li/electrolyte/ATO cells. The ATO film electrodes show high specific capacity, stable cycling performance and good rate performance. Discharge capacities were 1482, 973, 636, and 447mAhg−1 for the first, second, 100th and 200th cycles, respectively. Electrochemical reaction products of ATO films in the cell were examined by analyzing the phase evolution of the ATO electrodes electrochemically induced at various stages using high resolution transmission electron microscopy. The results reveal the electrochemical reaction as follows: the decomposition of SnO2 and formation of metallic Sn and Li-Sn alloy during discharge process; reversible de-alloying of Li-Sn, reaction between Sn and Li2O, and even partial formation of SnO2 during charge process. Nano-structured characteristics were maintained during the charge-discharge processes, to which good electrochemical performance of the ATO thin films is mainly attributed.

Electrical and Optical Properties of Solution-Based Sb-Doped SnO2 Transparent Conductive Oxides Using Low-Temperature Process

Solution-based Sb-doped <TEX>$SnO_2$</TEX> (ATO) transparent conductive oxides using a low-temperature process were fabricated by an electrospray technique followed by spin coating. We demonstrated their structural, chemical, morphological, electrical, and optical properties by means of X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, atomic force microscopy, Hall effect measurement system, and UV-Vis spectrophotometry. In order to investigate optimum electrical and optical properties at low-temperature annealing, we systemically coated two layer, four layer, and six layers of ATO sol-solution using spin-coating on the electrosprayed ATO thin films. The resistivity and optical transmittance of the ATO thin films decreased as the thickness of ATO sol-layer increased. Then, the ATO thin films with two sol-layers exhibited superb figure of merit compared to the other samples. The performance improvement in a low temperature process (<TEX>$300^{\circ}C$</TEX>) can be explained by the effect of enhanced carrier concentration due to the improved densification of the ATO thin films causing the optimum sol-layer coating. Therefore, the solution-based ATO thin films prepared at <TEX>$300^{\circ}C$</TEX>C exhibited the superb electrical (<TEX>${\sim}7.25{\times}10^{-3}{\Omega}{\cdot}cm$</TEX>) and optical transmittance (~83.1 %) performances.

Electrical and Optical Properties of Sb-doped SnO2 Thin Films Fabricated by Pulsed Laser Deposition

Electrical and Optical Properties of Sb-doped SnO2 Thin Films Fabricated by Pulsed Laser Deposition

Enhanced Photoelectrochemical Water Splitting Efficiency of a Hematite–Ordered Sb:SnO2 Host–Guest System

Host-guest systems such as hematite/SnO2 have attracted a great deal of interest as photoanodes for photoelectrochemical water splitting. In the present work we form an ordered porous tin oxide layer formed by self-organizing anodization of Sn films on a FTO substrate. Subsequently the anodic tin oxide nanostructure is doped with antimony (ATO) by a simple impregnation and annealing treatment, and then decorated with hematite using anodic deposition. Photoelectrochemical water splitting experiments show that compared to conventional SnO2 nanostructures, using a Sb doped nanochannel SnO2 as a host leads to a drastic increase of the water splitting photocurrent response up to 1.5 mA cm(-2) at 1.6 V (vs. RHE) in 1 M KOH under AM 1.5 (100 mW cm(-2) ) conditions compared to 0.04 mA cm(-2) for the non-Sb doped SnO2 scaffold.

Computer Screening of Dopants for the Development of New SnO2-Based Transparent Conducting Oxides

Transparent conducting oxides (TCOs) are unique materials with high electrical conductivity and optical transparency and have been extensively used in optoelectronic devices. However, the prototype n-type TCO, Sn-doped In2O3 (ITO), is limited by the rarity and high cost of indium. In contrast, SnO2 is a promising alternative candidate, which is a low-cost and nontoxic material and also exhibits electrical and optical properties, compared to those of ITO. Here, we present a first-principles-based computer screening system to search for suitable dopants for monodoping or codoping SnO2 to develop new SnO2-based TCO materials. The screening is based on an efficient and reliable way of calculating the effective mass, the band gap, the formation energy, and the binding energy. The outcomes of the screening include all already known successful SnO2-based TCO materials (Sb-doped SnO2, ATO; F-doped SnO2, FTO) and also some new ones (P-doped SnO2, PTO; F and P codoped SnO2, FPTO), which would be hopeful materials of interest for further experimental validation.

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.

Pt nanoparticles supported on Sb-doped SnO2 porous structures: developments and issues

In this work, high surface area antimony doped tin oxide (Sb-SnO2) has been synthesized using a modified sol-gel synthesis method. The bulk and surface properties of the metal oxide support have been investigated as a function of the processing conditions. A change in the Sb-SnO2 processing conditions, while preserving an overall invariant bulk composition, led to substantial modification of the surface stoichiometry. Accelerated stability test protocols have shown that the surface composition represents a crucial parameter for the electrochemical stability of Sb-SnO2. Model Pt/Sb-SnO2 electrodes have been developed depositing Pt nanoparticles by magnetron sputtering on the optimized Sb-SnO2 porous surface. A significant enhancement in the corrosion stability upon 1000 potential cycles between 0.5 and 1.5 V (RHE) at 50 mV s(-1) has been observed for the Pt/Sb-SnO2 system compared to Pt/carbon.

Prediction of dopant atom distribution on nanocrystals using thermodynamic arguments

A theoretical approach aiming at the prediction of segregation of dopant atoms on nanocrystalline systems is discussed here. It considers the free energy minimization argument in order to provide the most likely dopant distribution as a function of the total doping level. For this, it requires as input (i) a fixed polyhedral geometry with defined facets, and (ii) a set of functions that describe the surface energy as a function of dopant content for different crystallographic planes. Two Sb-doped SnO2 nanocrystalline systems with different morphology and dopant content were selected as a case study, and the calculation of the dopant distributions expected for them is presented in detail. The obtained results were compared to previously reported characterization of this system by a combination of HRTEM and surface energy calculations, and both methods are shown to be equivalent. Considering its application pre-requisites, the present theoretical approach can provide a first estimation of doping atom distribution for a wide range of nanocrystalline systems. We expect that its use will support the reduction of experimental effort for the characterization of doped nanocrystals, and also provide a solution to the characterization of systems where even state-of-art analytical techniques are limited.