Antimony-doped Tin Oxide Research Articles

Oxide-on-Oxide Porous Electrodes Revealing Superior Reversible Li+-Coupled Electron-Transfer Properties by Unconventional Heterojunction Effects.

Internal spacing of electrodes is a key point for controlling electron-transfer (ET)-related phenomena. However, their disordered porous structures often prevent the observation of microscopic effects. It hampers the development of modern electrochemical theories. The development of model porous electrodes therefore provides an ideal platform to discover intriguing fundamental principles of electrode processes. We developed a new synthetic strategy for all-oxide monolithic ruthenium dioxide (RuO2)/antimony-doped tin oxide (ATO) electrodes with a controlled hierarchically porous structure and oxide-oxide heterojunction. The use of the obtained RuO2/ATO electrodes as model electrodes suppressed influences related to different mass diffusion efficiencies between electrodes with heterojunctions of different types. Then, we showed unconventional oxide-oxide heterojunction effects, improving reversible Li+-coupled electron-transfer properties using model electrodes constituted of various nanostructured (nano-) RuO2 on porous ATO. In addition to the superior electrochemical properties of the nano-RuO2/ATO heterojunction, the quasi-two-dimensional (2D) RuO2/ATO heterojunction led to improved specific capacity at a high rate and longer cycle life. We anticipate that this oxide-oxide heterojunction effect and developed all-oxide model porous electrodes can provide a path to develop advanced reversible energy storage devices.

Cover Feature: Photothermal Oxidation of Cinnamyl Alcohol with Hydrogen Peroxide Catalyzed by Gold Nanoparticle/Antimony‐Doped Tin Oxide Nanocrystals (Chem. Eur. J. 46/2022)

Gold nanoparticle-loaded, antimony-doped tin oxide nanocrystals (Au/ATO NCs) show thermally activated catalytic activity for the oxidation of cinnamyl alcohol to cinnamaldehyde by hydrogen peroxide. Light irradiation (λex>660 nm, ∼0.5 sun) of Au/ATO NCs gives rise to a more than twofold increase in the rate of reaction with ∼95 % selectivity. Kinetic analyses indicated that the striking enhancement of the reaction stems from the rise in the temperature near the catalyst surface of ∼30 K due to the photothermal effect of the ATO NCs. More information can be found in the Research Article by H. Tada and co-workers (DOI: 10.1002/chem.202201653).

Efficient solar-driven interfacial water evaporation enabled wastewater remediation by carbonized sugarcane

Solar-driven interfacial water evaporation has great potential in wastewater remediation. Carbonized biomass materials emerged as attractive solar evaporators due to their excellent solar harvesting, solar-thermal converting, and water delivering capabilities. In this study, antimony doped tin oxide (ATO) was loaded to sugarcane that was then carbonized to obtain composite solar evaporator CS@ATO which delivered a solar absorption of 99 %, a solar evaporation rate of 1.43 kg m−2 h−1 and an efficiency of 95.3 %. Treated with CS@ATO, the concentrations of heavy metal ions in wastewater were reduced by 3–4 orders, and dyes in wastewater were removed almost completely. For seawater desalination with CS@ATO, the contents of the main cations in the collected fresh water were lower than the levels in drinking water defined by WHO. CS@ATO also exhibited long-term service capability in both wastewater remediation and seawater desalination. These results suggested great potential of CS@ATO in the aforementioned environment related applications.

(Digital Presentation) Improved Nanocatalysts, Supported IrOx and IrRuOx, for Enhanced Oxygen Evolution Reaction

The production of hydrogen via acidic electrochemical water splitting is an important pillar towards more sustainability. The overall water electrolysis is hindered by the slow kinetics of the oxygen evolution reaction (OER). Therefore, the catalyst material for the anode still requires optimization. Hereby, we present two highly active OER catalysts, IrOx and Ir0.4Ru0.6Ox nanoparticles (NPs), prepared by a straightforward, surfactant-free, colloidal synthetic route.1 The metallic NPs are ~1.5 nm in diameter and were deposited on carbon Ketjen Black (CKB) as well as on antimony doped tin oxide (ATO) to investigate the active phase as well as potential influences of the support material. After the colloidal synthesis and supporting, the catalysts were activated, thus undergoing a particle growth of ~1 nm. Their performance was benchmarked in terms of activity and stability using our recently developed electrochemical flow cell called gas diffusion electrode (GDE) setup.2 This novel approach allows closing the experimental gap between the two most common methods, namely the rotating disk electrode (RDE) and the membrane electrode assembly (MEA). Independently from the support, Ir0.4Ru0.6Ox shows a higher activity towards OER than IrOx at three tested temperatures, i.e. 30, 40, 60 °C. The two different support materials were also compared, and it was found that independently from the material, NPs deposited on CKB showed slightly higher activity at low current densities (up to 40 mA mgIr -1). As expected, accelerated potentiostatic stability test reveals a rapid degradation of the IrOx/CKB, while IrOx/ATO and Ir0.4Ru0.6Ox/ATO exhibit similar stability than commercially available Ir black.[1] Francesco Bizzotto, Jonathan Quinson, Alessandro Zana, Jacob J. K. Kirkensgaard, Alexandre Dworzak, Mehtap Oezaslan, Matthias Arenz, Catal. Sci. Technol., 2019, 9, 6345-6356.[2] Johanna Schröder, Vladislav A. Mints, Aline Bornet, Etienne Berner, Mohammad Fathi Tovini, Jonathan Quinson, Gustav K. H. Wiberg, Francesco Bizzotto, Hany A. El-Sayed, Matthias Arenz, JACS Au, 2021, 1, 247-251. Figure 1

Electrochemistry on the Edge: Advancing High Oxidation Power Materials for Applications at Strongly Oxidizing Potentials

High oxidation power (HOP) materials such as lead(IV) oxide (PbO2), antimony-doped tin(IV) oxide (ATO), Magnéli phase titanium oxides (MPTOs), and boron-doped diamond (BDD) are important for advancing electrochemical technologies for clean water and energy applications. Specifically, these include electrocatalytic materials for electrolyzers for water treatment applications and electrosynthesis applications, supports for electrocatalysts for fuel cells and electrolyzers for hydrogen production and electrosyntheses, and electrically-conductive filler in batteries. However, issues of toxicity (PbO2), stability (ATO, MPTOs), and cost (BDD) must be addressed if HOPs are to be more-broadly used as alternatives to carbon-based materials. The Wilkinson group at the University of British Columbia has recently prepared transition metal doped Ti4O7, a MPTO, which exhibits improved characteristics as an electrode material [1,2]. Specifically, thermogravimetric analysis and electrochemical accelerated life testing (Figs. a & b, respectively), illustrate its superior resistance to oxidation while use of the 4-point probes method reveals greater electrical conductivity relative to pristine Ti4O7. The preparation of these materials and their characterization as well as their eventual incorporation into electrochemical devices for clean water and energy applications will be discussed. Figure 1

Antimony-Doped Tin Oxide Catalysts for Green and Sustainable Chemistry

Antimony-Doped Tin Oxide Catalysts for Green and Sustainable Chemistry

Noble Metal-Free Inorganic Photocatalyst Consisting of Antimony-Doped Tin Oxide Nanorod and Titanium oxide for Two-Electron Oxygen Reduction Reaction.

This study reports a noble metal-free robust inorganic photocatalyst for H2 O2 synthesis via two-electron oxygen reduction reaction (ORR). Antimony-doped tin oxide nanorods were heteroepitaxially grown from rutile TiO2 seed crystals with an orientation of (001)ATO //(001)TiO2 (ATO-NR//TiO2 ,//denotes heteroepitaxial junction) by a hydrothermal method. UV-light irradiation of ATO-NR//TiO2 particles stably and continuously produces H2 O2 from aerated aqueous solution of ethanol. Electrochemical measurements using rotating electrodes show that Sb-doping into SnO2 greatly enhances the electrocatalytic activity for two-electron ORR. The striking photocatalytic activity of ATO-NR//TiO2 stems from the effective charge separation, electrocatalytic activity for two-electron ORR, low catalytic activity for H2 O2 decomposition, and extraordinary robustness.

High-performance non-fullerene acceptor inverted organic photovoltaics incorporating solution processed doped metal oxide hole selective contact

Inverted organic photovoltaics (OPVs) allow flexibility on designing a roll-to-roll production process of OPVs, providing technological opportunities. The OPV roll-to-roll production process demands thick and high-performance solution-based hole selective contacts. Here, we show that a solution processed antimony-doped tin oxide (ATO) hole selective contact produced by spray pyrolysis route exhibits exceptional optoelectronic properties and functionality within non-fullerene acceptor PM6:Y6:PC70BM inverted OPVs. The corresponding solution processed inverted OPVs provide high power conversion efficiency values when a thick hole selective contact of solution processed doped ATO is incorporated within the inverted OPV device structure and similar light stability to that achieved with the commonly used thermally evaporated MoO3 hole selective contact.

Highly transparent and super-wettable nanocoatings hybridized with isocyanate-silane modified surfactant for multifunctional applications

Highly transparent and super-wettable nanocoatings for multifunctional applications with outstanding physical properties are in high demanded. However, such nanocoatings resistant to water invasion and Ultraviolet (UV) weathering remain a significant challenge. In this work, physically durable coatings based on inorganic nanoparticles (NPs) and an organic segment (isocyanate-silane modified surfactant) have been synthesized via a sol-gel approach. It is noteworthy the isocyanate-silane with –NH–CO- functional group creates a strong bonding between the highly hydrophilic surfactant and the inorganic NPs. This in-house synthesized organic segment can render the coating long-lasting wetting properties and resist to be washed away by water, while the inorganic NPs can form sturdy covalent bonds with the nano-scale hierarchical structure on the glazing substrate to improve the durability. This nanocoating demonstrates high transparency with superwetting property (water contact angle, WCA ​= ​4.4 ​± ​0.3°), effective de-frosting performance. Water invasion or UV accelerated weathering tests do not significantly affect the self-cleaning performance of nanocoating. Physical properties, including coating adhesion, hardness, Young's modulus, and abrasion resistance are systematically investigated. Interestingly, this clear coating shows prominent infrared shielding property attributed to Antimony-doped tin oxide (Sb-doped SnO2) NPs. The developed nanocoating process is easy to scale up for larger areas that require multipurpose self-cleaning functions.

Insight into the role of the channel in photothermal materials for solar interfacial water evaporation

The porous solar-driven interfacial evaporator has attracted substantial interest because of its high performance in converting solar energy into heat for water evaporation. However, the effect mechanism of porous structure (e.g., pore size and porosity) on water evaporation efficiency remains controversial and unclear, which largely restricts the design of high-performance solar evaporators. Herein, a porous solar interfacial evaporator with controllable porous structure was presented by integrating carbonized carboxymethyl cellulose with antimony doped tin oxide (ATO) powder (ATO-C). The experimental results revealed that reducing the porosity of ATO-C could reduce heat loss for heating the water inside channels, thereby improving the evaporation efficiency. Moreover, the synergistic light absorption of carbonized cellulose (in the visible region) and ATO (in the near-infrared light region) enable ATO-C to harvest a large fraction of sunlight (more than 98%) for water evaporation. On the basis, the ATO-C exhibited a water evaporation rate up to 1.44 kg m−2 h−1 under one solar irradiation with an evaporation efficiency of 90.38%, outperforming most previously reported solar evaporators. The current work clarifies the effect mechanism of porosity on evaporation efficiency, which helps to develop high-performance solar interfacial water evaporators.

Carbon-Free Reversible Air Electrodes based on Perovskite Oxide and Conductive Oxide for Rechargeable Zinc-Air Batteries

Reversible air electrodes with high activity and durability during the discharge/charge processes are required for rechargeable zinc-air batteries. Although carbon materials are widely used as catalyst supports and conductive additives for metal oxide catalysts in the catalyst layer (CL) and as the main active constituent in the gas-diffusion layer (GDL), the carbon is oxidized during the charge step, causing degradation of the air electrode. In this study, carbon-free air electrodes were prepared using electro-conductive oxides, namely, indium tin oxide or antimony-doped tin oxide, as an alternative to carbon materials in both the CL and GDL to achieve reversibility and durability of the air electrode in zinc-air batteries. While the initial performance of the carbon-free air electrodes was inferior to that of the carbon-based air electrodes, the lifetime of the carbon-free air electrodes was remarkably longer. These results indicate a critical role of electro-conductive oxides in both the CL and GDL for durable air electrodes.

Highly Active and Renewable Catalytic Electrodes for Two-Electron Oxygen Reduction Reaction.

This study has shown that antimony-doped tin oxide (ATO) works as a robust "renewable catalyst" for the electrochemical synthesis of hydrogen peroxide (H2O2) from water and oxygen. Antimony doping into SnO2 gives rise to remarkable electrocatalytic activity for two-electron oxygen reduction reaction (2e--ORR) by water with a volcano-type relation between the activity and doping levels (xSb). Density functional theory simulations highlight the importance of an isolated Sb atom of ATO inducing the high activity and selectivity for 2e--ORR due to the effects of O2 adsorption enhancement, decrease in the activation energy, and lowering the adsorptivity of H2O2. Electrolysis by a normal three-electrode cell using ATO (xSb = 10.2 mol %) at -0.22 V (vs reversible hydrogen electrode) stably and continuously produces H2O2 with a turnover frequency of 6.6 s-1. This remarkable activity can be maintained even after removing the surface layer of ATO by argon-ion sputtering.

Performance analysis of aqueous Al-ion electrolyte based dye sensitized solar cell

Photovoltaic performance of the aqueous Al-ion electrolyte-based dye-sensitized solar cells (DSSCs) was investigated by varying the aluminium nitrate concentration, ranging from 0.02 to 0.1 M and using Eosin-Y (EY) sensitized antimony-doped tin oxide (ATO) photoanode with platinum (Pt) as counter electrode. Photoconversion efficiency (PCE) peaks for 0.1 M using the source of 100 mW cm−2 with AM 1.5G (standard) solar simulator under ambient condition, photocurrent density (JSC) reaches 3.76 mA/cm2 and efficiency (PCE, η) 3.17%. Most of the work that exist in literature with (K, Na, Co, Li, etc. based) aqueous electrolyte quoted the maximum efficiency 1.55% whereas, the present work with pure aqueous Al-ion electrolyte gives 50% of higher efficiency over the quoted value. Moreover compared to the undoped tin oxide photoanode, this work with Sb doped tin oxide shows an enhancement of efficiency about 80%.

Electrochemical activation of peroxydisulfate by Ti/ATO electrode: Performance and mechanism

Antimony-doped tin oxide electrode (Ti/ATO) has received much attention in electrochemical water treatment owing to its high oxygen evolution potential (OEP) and low cost. This study mainly focuses on the electrochemical activation behaviour of peroxydisulfate (PDS) using a Ti/ATO electrode. The catalytic performance of the Ti/ATO-electro-activated PDS system was systematically investigated. The effects of different operating conditions on the RhB degradation rate, including electrolyte pH, PDS concentration, current density, and coexisting anions, were experimentally analysed. Quenching experiments, EPR, and electrochemical methods were used to identify the dominant reactive oxygen species (ROS) induced in the Ti/ATO electro-activated PDS system. Diverse radical and non-radical oxidations were verified to exist in the Ti/ATO electro-activated PDS system. We simulated the proposed reaction pathways of persulfate ion on the SnO2 surface using first-principles calculations. Computational results imply that persulfate ions are more easily activated into SO4− when adsorbing on the surface of SnO2. Furthermore, all the feasible oxidation processes which had made contribution to the RhB removal in Ti/ATO electro-activated PDS system were discussed. This work offers a new and effective strategy for electrochemical PDS activation and a viable technique for wastewater treatment.

VO2/ATO nanocomposite thin films with enhanced solar modulation and high luminous transmittance for smart windows

Developing an economic, facile strategy to prepare high-efficiency VO2-based thin films is critical to thermochromic smart windows. It is still challenging to simultaneously achieve high luminous transmittance (Tlum) and large solar modulation (ΔTsol). In this paper, the composites of VO2 nanoparticles and antimony-doped tin oxide (ATO) nanoparticles are prepared to significantly boost the overall performances of the films. As compared with pristine VO2, the Tlum value of the composite films is substantially increased from 30.91% to 84.35% by 170%, while a suitable ΔTsol value of 11.57% is almost maintained. Furthermore, an optimized overall performance of Tlum (60.14%) and ΔTsol (20%) is achieved. The excellent optical properties are closely related with the dispersive small particles and widened optical band gap. The results provide an effective strategy for enhanced performances of smart windows.

Green synthesis of tin oxide based nanoparticles using Terminalia bellirica seed extract: impact of operating temperature and antimony dopant on sensitivity for carbon dioxide gas sensing application

ABSTRACT Green synthesis of undoped tin oxide (SnO2) and 2 wt% antimony doped tin oxide (Sb:SnO2) for carbon dioxide (CO2) gas sensing application is reported. The structural, morphological and optical properties of nanoparticles were investigated using XRD, SEM, EDX, HRTEM, FTIR and UV-Vis characterisation techniques. CO2 gas sensing studies were carried out by using calibration setup on pellets of nanoparticles. From XRD, SEM and HRTEM analysis, the average size of Sb:SnO2 nanoparticles were found decreased than the SnO2 nanoparticles. EDX analysis indicated the presence of tin, antimony and oxygen elements in the structure of nanoparticles. The presence of functional groups responsible for the formation of nanoparticles was identified by FTIR spectra. Bandgap of SnO2 and Sb:SnO2 nanoparticles was found to be 3.67 eV and 3.47 eV respectively. The sensitivity of SnO2 and Sb:SnO2 nanoparticles at the optimized operating temperature was found as 18.32% and 35% at 1000 ppm CO2 gas concentration.

Highly sensitive, direction-aware, and transparent strain sensor based on oriented electrospun nanofibers for wearable electronic applications

Wearable strain sensors have made great progress in sensing performance, stretchability and durability. However, practical applications of these sensors are still quite challenging because they are incapable of detecting multi-degree-of-freedom strains due to the interference of multidirectional strains. Herein, a high-sensing-performance, direction-aware and transparent strain sensor is reported based on antimony-doped tin oxide oriented nanofiber (ATO-ONF) films prepared by electrospinning. The monolayer ATO-ONF strain sensor shows remarkable anisotropic sensing performance, namely GFs of 250 and 1.2 for the nanofiber orientation and its transverse directions, suggesting the realization of the unidirectional sensing capability of the strain sensor, i.e., only responding to strains along the nanofiber direction. In addition, this strain sensor also exhibits high transparency with a light transmittance of ∼ 80%, and excellent sensing performance including high sensitivity, high linearity, low hysteresis, good repeatability and durability (>2000 cycles). Based on these superior sensing properties, the direction-aware biaxial strain sensor is designed by orthogonally stacking ATO-ONF films, by which the predicted magnitude and direction of the tensile strains agree well with those of the actual strains. Furthermore, the multi-degree-of-freedom applications of direction-aware strain sensors in human motion monitoring and human–machine interaction are demonstrated, showing a great application potential in next-generation wearable electronics.

Development of ATO as an alternative catalyst support for PEM fuel cells

Proton exchange membrane (PEM) fuel cells demonstrated to be feasible energy converters that convert chemical energy of fuels to electrical energy. The technology has proven to be competitive with conventional energy converters such as batteries and internal combustion engines. However; several challenges influence the commercialization of this technology which includes high costs, durability, and stability, which are contributed by the PEM fuel cell catalysts. Currently, the carbon-supported platinum electro-catalyst is being used. Unfortunately, carbon supports are not stable enough for fuel cell durability due to carbon corrosion on the cathode. Therefore it is necessary to replace carbon support materials to improve the durability of PEM fuel cells. In this study, antimony doped tin oxide (ATO) metal oxides are synthesized as alternative platinum catalyst support via co-precipitation with different antimony doping levels of 5, 7, and 10 %. The preliminary results of the acid resistance test show that the support is relatively acid-resistant with minor loss of dopant in acidic conditions. Surface area measurements, XRD, TEM, ICP characterization will be performed on the ATO before and after the addition of 40 wt. % of Pt particles. The mass and specific activity measurements for oxygen reduction reaction (ORR) and durability via ex-situ thin-fil rotating disc electrode (RDE) of Pt/ATO catalyst and the traditionally used Pt/C catalyst will be compared.

Cellulose-derived solid-solid phase change thermal energy storage membrane with switchable optical transparency

Switchable optical transparency is an intrinsic property for solid–liquid phase change materials (PCMs) during phase change processes. However, due to non-transparent porous confinement materials and core-shell structures, the synthesis of shape-stabled PCMs typically sacrifices their switchable optical transparency. Here, we present a copolymerization-induced shape-stabilization strategy that uses cellulose 10-undecenoyl ester (CUE) as a polymer-based crosslinker and a variety of alkyl acrylates (AAs) as phase change monomers to produce solid–solid phase change membranes (CUE-AAs) with high efficient thermal energy storage and excellent thermo-reversible optical transparency. These as-prepared CUE-AAs membranes present excellent switchable optical transparency from approximately below 5% to over 90% during phase change processes, and the responsive temperature of the transparency could be tailored in the range of 23–67 °C by using different AAs. Furthermore, three kinds of n-alkanes including hexadecane, octadecane, and docosane were physically entrapped in the CUE-AAs cross-linked networks to enhance the thermal energy storage performance, leading to a maximum melting enthalpy of up to 166.5 J/g. Moreover, the introduction of surface modified antimony-doped tin oxide nanoparticles significantly improved the light-to-thermal conversion effect, endowing the resulted membranes with high potential in application as thermal management material. Thus, the diverse properties of these CUE-AAs based PCMs, such as excellent thermo-reversible optical transparency, high thermal energy storage performance, remarkable photo-thermal storage efficiency, and high thermal stability, made them suitable for a wide range of applications, including intelligent optical devices and solar energy storage devices.

Optoelectronic Properties of Antimony Doped Tin Oxide Thin Films Obtained by Spray Pyrolysis

Antimony doped tin oxide (ATO) thin films are deposited on corning glass substrate using the spray pyrolysis technique. The experimental parameters such as distance between the substrate and source (10-30 cm), substrate temperature (350-450°C) and atmospheres (Nitrogen and Forming gas) are varied to study their effect on the properties of ATO thin films. The ATO thin film annealed at 425°C exhibits the lowest electrical resistivity of 2.23×10-2 Ω-cm. Besides, the film annealed in the nitrogen atmosphere showed a less resistivity value of 9.06×10-3 (Ω-cm) than the forming gas atmosphere. The film doped with 3 at% of Sb revealed the highest figure of merit value of 11.45x10-2 Ω-1. The preferential orientation is observed at the (200) diffraction plane in all the cases from the structural studies. Furthermore, the intensity of the diffraction planes decreases as the temperature increases. The average transmittance of 75% is obtained for ATO thin films.