Sb-doped SnO2 Research Articles

Ni- and Sb-Doped SnO2 Electrocatalysts with High Current Efficiency for Ozone Production via Electrodeposited Nanostructures

Ozone is a powerful disinfectant in water treatment, and electrochemical ozone production (EOP) is desirable because it can be safer than current production methods. The greatest challenge for electrochemical ozone production is the lack of catalysts with high selectivity for ozone evolution. Nickel- and antimony- doped tin oxide electrodes synthesized from sol-gels and nanoparticles have been reported to reach ozone current efficiencies up to 50% for electrochemical ozone production. In this study, we present a novel electrodeposition synthesis method that results in current efficiencies up to 63%. The optimal temperature of the post-deposition oxidation treatment is determined by the tradeoff between catalyst stability and crystallinity. Analysis via microscopy and X-ray diffraction suggests that electrodeposited films provide sufficient Ni concentration, surface area, and morphology to support a solution-mediated ozone production reaction.

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.

Evaluation of new ceramic electrodes based on Sb-doped SnO2 for the removal of emerging compounds present in wastewater

The properties of the ceramic electrodes make them interesting for electrochemical advanced oxidation processes (EAOPs), destined to the elimination of emergent or refractory contaminants, as an alternative to boron-doped-diamond (BDD) electrodes. For this purpose, new ceramic electrodes based on Sb-doped SnO2 have been developed. Sb-doped tin oxide electrodes have been obtained through mechanical mixing of raw materials and sintering of dry-pressed specimens. Different sintering temperatures (1050°C to 1250°C) were considered. The electrochemical behavior of the resulting electrodes has been compared to that exhibited by Pt and BDDs electrodes. The oxygen discharge potential (EO2) for the ceramic electrodes decreases as the sintering temperature increases, being these values higher than that observed for the Pt electrode and smaller than that for the BDD electrode. This result in a highest rate of COD removal for the electrode sintered at 1050°C comparing with the rest of ceramic electrodes under potentiostatic operation. On the other hand, in galvanostatic mode, the performance of the different ceramic electrodes in terms of the degradation of Norfloxacin, used as tested antibiotic, was similar.Comparing the behavior of the ceramic electrode sintered at 1250°C and that of the BDD electrode at an applied potential of 3V, it is inferred that although both present similar values in terms of the degradation of Norfloxacin, the rate of removal of the chemical oxygen demand is higher in the case of the BDD.

Single-Atom Catalysts of Precious Metals for Electrochemical Reactions.

Single-atom catalysts (SACs), in which metal atoms are dispersed on the support without forming nanoparticles, have been used for various heterogeneous reactions and most recently for electrochemical reactions. In this Minireview, recent examples of single-atom electrocatalysts used for the oxygen reduction reaction (ORR), hydrogen oxidation reaction (HOR), hydrogen evolution reaction (HER), formic acid oxidation reaction (FAOR), and methanol oxidation reaction (MOR) are introduced. Many density functional theory (DFT) simulations have predicted that SACs may be effective for CO2 reduction to methane or methanol production while suppressing H2 evolution, and those cases are introduced here as well. Single atoms, mainly Pt single atoms, have been deposited on TiN or TiC nanoparticles, defective graphene nanosheets, N-doped covalent triazine frameworks, graphitic carbon nitride, S-doped zeolite-templated carbon, and Sb-doped SnO2 surfaces. Scanning transmission electron microscopy, extended X-ray absorption fine structure measurement, and in situ infrared spectroscopy have been used to detect the single-atom structure and confirm the absence of nanoparticles. SACs have shown high mass activity, minimizing the use of precious metal, and unique selectivity distinct from nanoparticle catalysts owing to the absence of ensemble sites. Additional features that SACs should possess for effective electrochemical applications were also suggested.

Stable Electrocatalysts Based on Potential-Dependent Switching of Metal Oxide Support Conductivity

Metal oxides are gaining increasing interest in electrocatalysis research as alternative to commonly used high surface area carbon supports for electrocatalyst nanoparticles. On the one hand, metal oxide supports can offer improved corrosion resistance in electrocatalytic processes occurring at high electrode potentials where carbon supports suffer from severe oxidation. On the other hand, intrinsic catalytic properties of the supported catalyst nanoparticles can be influenced by interactions between catalyst and metal oxide support. Thus, metal oxides open a wide field for optimization of supported electrocatalysts similar to the situation in heterogeneous catalysis. However, in electrocatalysis applications, electronic conductivity of the support material is necessary, a requirement which is difficult to be met by metal oxides. Whereas few metal oxides possess intrinsic metallic conductivity, a wider selection of semiconducting materials is achieved by generating defects, such as dopant atoms or oxygen vacancies, inside the lattice of an intrinsically isolating metal oxide. Our research on semiconducting Sb-doped SnO2 (ATO) support for Pt nanoparticles in the context of oxygen reduction reaction (ORR) electrocatalysis revealed a fundamental descriptor for the choice of suitable metal oxide support materials [1]: Well-known from the theory of the semiconductor–electrolyte interface, the metal oxide flat-band potential separates the potential range where the oxide surface is enriched with mobile charge carriers from the potential range of charge carrier depletion leading to a drastically reduced support conductivity at certain electrode potentials. This potential-dependent in situ conductivity switching can be seen as direct electrochemical analog of a field-effect transistor. On the one hand, this electrochemical transistor effect can limit metal oxide support conductivity and, therefore, electrocatalyst performance if the conductivity switching potential, i.e. the metal oxide flat-band potential, overlaps with the potential range of application. On the other hand, as shown for Pt/ATO ORR catalyst, the electrochemical transistor switching of ATO conductivity has a highly beneficial effect on the stability of supported Pt nanoparticles by limiting electrochemical dissolution and Ostwald ripening at high electrode potentials. Therefore, the electrochemical transistor effect of metal oxide supports offers a way for the development of ORR catalysts combining high performance with strongly improved stability. Acknowledgement This work was supported by CCEM Switzerland and Umicore AG & Co KG within the project DuraCat. The authors thank the BESSY II synchrotron at Helmholtz-Zentrum Berlin, Germany, for providing beamtime at the 7T MPW SAXS beamline.

Perylene Diimide Aggregates on Sb-Doped SnO2: Charge Transfer Dynamics Relevant to Solar Fuel Generation

The deposition of perylene diimide-based aggregates (PDI) onto wide band gap n-type Sb-doped SnO2 (ATO) was investigated with the aim of finding efficient and versatile dye-sensitized platforms for photoelectrochemical solar fuel generation. These ATO-PDI photoanodes displayed hydrolytic stability in a wide range of pH (from 1 to 13) and revealed superior performances (up to 1 mA/cm2 net photocurrent at 1 V vs SCE) compared to both WO3-PDI and undoped SnO2-PDI when used in a photoelectrochemical setup for HBr splitting. Although ATO, SnO2, and WO3 are endowed with similar conduction band edge energetics, in ATO the presence of a significant density of intrabandgap states, whose occupancy varies with the applied potential, plays a substantial role in tuning the efficiency of photoinduced charge separation and collection. Furthermore, the investigation of the charge injection kinetics confirmed that, even in the absence of applied bias, ATO and WO3 are the best substrates for the oxidative quenching of poor...

An efficient Sb-SnO2-supported IrO2 electrocatalyst for the oxygen evolution reaction in acidic medium

Polymer (acidic) electrolyte membrane water electrolysis suffers from insufficient catalyst activity, high cost of noble metal, and unsatisfactory durability, due to the sluggish reaction kinetics of oxygen evolution reaction and poor stability of catalysts under harsh operating environments. Aiming to enhance the utilization and durability of noble metals, a mesoporous Sb-doped SnO2 material with high surface area and conductivity was synthesized via soft-template method to support IrO2 catalyst. Physical characterization reveals that the as-prepared composite exhibits a rough morphology with the weak crystallinity IrO2 upper layer covering the rutile SnO2 crystalline phase. Electrochemical test for the IrO2-loading-dependant activity finds that both the area-free activity and mass-specific current on the 31 wt% sample are the optimal, meaning the excellent dispersion effect coming from the mesoporous Sb-SnO2 support and the synergy between the catalytic particles and Sb dopant. In addition, the enhancement in mass transfer efficiency and conductivity coming from the porous, IrO2-covered cross-linked morphology and the support-active component interaction, the supported IrO2 with 50 wt% loading marks the maximum normalized charge (227 C g−1 IrO2) and the highest apparent current at 1.75 V. What is more, this composite catalyst with the noble metal oxide coating is much more durable during continuous oxygen evolution procedure under a constant potential of 1.6 V because of the anchor effect from the carrier on the catalyst and a protective effect from the noble metal layer on the non-acid-tolerant support.

Structural, morphological, optical and electrical properties of Sb-doped SnO2 thin films obtained by aerosol assisted chemical vapor deposition

In this work, we report the synthesis and characterization of antimony doped tin oxide thin films for their possible application as transparent conducting oxides. Thin films of antimony doped tin oxide were deposited by aerosol assisted chemical vapor deposition. Surface morphology and microstructure were studied by field emission scanning electron microscopy. X-ray diffraction results indicate the presence of two tin oxide phases in some samples (from thickness of 30–120nm) and only the cassiterite phase in samples with thicknesses greater than of 140nm. Optical properties of the samples were analyzed by total transmittance spectra. Resistivity of the films was obtained by the sheet resistance method. Electrical properties and conductivity type of samples were determined by Hall effect method. The results show low resistivity in antimony doped tin oxide materials decreasing up to six orders of magnitude compared to pure tin oxide, and obtaining resistivity in the order of magnitude of 10−4Ω·cm. Thermal treatment was performed on some materials and stability was observed because it did not decrease its resistivity and in addition the thermal treatment improved Hall mobility.

In Situ Monitoring of the Deposition of Flame-Made Chemoresistive Gas-Sensing Films.

Flame-deposited semiconducting nanomaterials on microelectronic circuitry exhibit exceptional performance as chemoresistive gas sensors. Current manufacturing technology, however, does not monitor in situ the formation of such nanostructured films, even though this can facilitate the controlled and economic synthesis of these sensors. Here, the resistance of such growing films is measured in situ during fabrication to monitor the creation of a semiconducting nanoparticle network for gas sensors. Upon formation of that network, the film resistance drops drastically to an asymptotic value that depends largely on the film structure or morphology rather than on its thickness and size of nanoparticle building blocks. Precursor solutions of various concentrations enable the flame deposition of Sb-doped SnO2 sensing films of different morphologies, each of which exhibit a characteristic in situ resistance pattern. Low precursor concentrations (1 mM) lead to thin (ca. 0.16 μm) films with slender columnar structures of increasing diameter (up to 25 nm) after prolonged deposition (up to 6 min) and show an oscillating in situ resistance during their fabrication. On the other extreme, high precursor concentrations (100 mM) lead to thick (up to 80 μm) dendritic and porous films consisting of nanoparticles with relatively small primary particle diameter (around 7 nm) that remain invariant of deposition duration, which is in agreement with the stable in situ resistance. Such dendritic films exhibit a sensor recovery time that is an order of magnitude longer than that of those made at lower concentrations. The above understanding enables the rapid and economic flame synthesis of thin gas sensors consisting of minimal semiconducting nanomaterial mass possessing a tuned baseline resistance and exhibiting excellent response to ethanol vapor.

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.

High figure of merit transparent conducting Sb-doped SnO2 thin films prepared via ultrasonic spray pyrolysis

Doped tin oxide has been studied extensively because of its potential as a replacement for indium tin oxide in transparent conducting oxide layers. Antimony-doped tin oxide (ATO) is one of the most promising materials in this regard, due to its superior transparency in the visible region and broad scope for electrical property improvements. In this paper, we report the fabrication of highly conductive transparent ATO thin films using a simple, low-cost ultrasonic spray pyrolysis method. A film with a resistivity of 5.8×10−5 Ω cm, transmittance of 88% at 550 nm, and figure of merit as high as 47.22×10−2 (Ω/cm2)−1 was produced by tuning the deposition time. The ATO films produced in this experiment may be used as transparent conducting films with performance comparable to that of indium tin oxide.

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.

Photoanode with Enhanced Performance Achieved by Coating BiVO4 onto ZnO-Templated Sb-Doped SnO2 Nanotube Scaffold

The performance of BiVO4 photoanodes, especially under front-side illumination, is limited by the modest charge transport properties of BiVO4. Core/shell nanostructures consisting of BiVO4 coated onto a conductive scaffold are a promising route to improving the performance of BiVO4-based photoanodes. Here, we investigate photoanodes composed of thin and uniform layers of BiVO4 particles coated onto Sb-doped SnO2 (Sb:SnO2) nanotube arrays that were synthesized using a sacrificial ZnO template with controllable length and packing density. We demonstrate a new record for the product of light absorption and charge separation efficiencies (ηabs × ηsep) of ∼57.3 and 58.5% under front- and back-side illumination, respectively, at 0.6 VRHE. Moreover, both of these high ηabs × ηsep efficiencies are achieved without any extra treatment or intentional doping in BiVO4. These results indicate that integration of Sb:SnO2 nanotube cores with other successful strategies such as doping and hydrogen treatment can increase the performance of BiVO4 and related semiconductors closer to their theoretical potential.

Thermal-frequency dependence study of the sub-band localized states effect in Sb-doped SnO2 based sol-gel thin films

Films of transparent conducting antimony-doped tin oxide have been deposited by sol-gel based Dip-coating technique. The morphological analysis revealed that the deposited films are homogenous, smooth and the roughness depends on the Sb-doping. The Raman scattering showed that the vibrational modes are sensitive to oxygen deficiency, structural disorder and were red-shifted compared to the rutile SnO2 single crystal. The FTIR study depicted the presence of SnO (610cm−1) and SnOSn (740cm−1) bonds in the films. Optical measurements revealed high transparency (~85%) over the visible region. The optical band gap varies from 3.87 to 3.79eV with increasing the width of tail states and corresponds to direct allowed transition in the bulk. The AC-conductivity (σac) exhibits a semiconductor temperature-dependence behavior and varies from extrinsic to intrinsic conduction. The thermal energy promotes the polarization involving electrons localized at randomly oriented oxygen vacancies of the inhomogeneous dielectric structure grain/grain boundary and induces high dielectric constant. σac was found to follow the power law: σac=A. f0.49 at high frequencies and the experimental results showed that the correlated barrier hopping mechanism is appropriate for the charge transfer between localized states.

Review of oxide coated catalytic titanium anodes performance for metal electrowinning

Conventional lead alloys are widely used in the zinc industry, in spite of their high overpotential and Pb contamination of the deposit during zinc electrowinning. The Oxide Coated Catalytic Anodes (OCAs) are considered to improve cathodic zinc purity and decrease cell voltage during zinc electrowinning. Considering the Ti substrate and its coatings such as (70%) IrO2+(30%) Ta2O5 coatings, the composites of OCAs have low overpotentials 400–500mV less than Pb-Ag anode. It was found that the oxygen evolution potential of the Ti/(Ir-Co) is 370mV lower than that of the lead alloy anode. Ta2O5 has more electric resistance than cobalt oxide and can lead to higher overpotentials. Also, RuO2 is an excellent electro-catalytic rutile structure. Considering generally a low cost coating of Ti substrate, Ni is more appreciable than that of zinc for the two systems of Co-Ni and Co-Zn coated over titanium. Addition of certain chemicals to the zinc electrolyte can decrease MnO2 deposition on the OCA anodes during zinc electrolysis. Moreover, the performance of OCA anodes increased with the nanoparticles addition of both IrO2 and the Sb-doped SnO2. To improve the service life of Ti substrate, procedures such as recrystallization, annealing treatment and surface anodic treatment could be employed. A conductive carbon-polymer has been developed to replace the titanium substrate, which is composed of graphite fibre, carbon black and polyolefin. Finally, aluminum has been studied for matrix because of its good electrical conductivity and mechanical strength.

Flame spray pyrolysis of tin oxide-based Pt catalysts for PEM fuel cell applications

SnO2 doped with Sb and Nb has been investigated for its use as catalyst support materials replacing carbon to enhance PEM fuel cells stability. Nanostructured powders of various doping levels were prepared by flame spray pyrolysis (FSP). The specific requirements of surface area >50 m2g−1 and electronic conductivity >0.01 Scm−1 were obtained, and pore sizes ranging mainly from 10 to 100 nm. Pt particles (9–20 wt.% in loading targeted) of ~1 nm well dispersed in Sb-doped SnO2 was prepared by a one-step FSP procedure providing microstructures of high interest for further investigations as cathode in PEM fuel cells.

Identification of the Mechanism of Electrocatalytic Ozone Generation on Ni/Sb-SnO2

This paper reports a systematic study of the codoping of SnO2 with Sb and Ni to identify the mechanism responsible for the electrocatalytic generation of ozone on Ni/Sb-SnO2. On the basis of interpretation of a combination of X-ray diffraction, BET surface area measurements (N2), and thermal analysis, the formation of ozone appears to take place on particle surfaces of composite Sb-SnO2 grains and is controlled by diffusion of OH along internal crystallite surfaces within the grain. Sb-doped SnO2 is inactive with respect to ozone evolution in the absence of Ni, demonstrating a synergic interaction between nickel and antimony. From X-ray photoelectron spectroscopy (XPS) investigations, Sb(V) ions substitute for Sn(IV) in the lattice with a preference for centrosymmetric coordination sites, while the Sb(III) ions occur at grain surfaces or boundaries. Ni was not detected by XPS, being located in the subsurface region at concentrations below the detection limit of the instrument. In addition to identificatio...

Hierarchical peony-like Sb-doped SnO2 nanostructures: Synthesis, characterization and HCHO sensing properties

Hierarchical peony-like Sb-doped SnO2 nanostructures were synthesized by a facile hydrothermal route and following calcination. The microstructure and morphology were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). Characterization results showed that as-prepared samples are uniform peony-like hierarchical nanostructures composed of edgy petal shaped nanosheets, and Sb element was uniformly distributed in SnO2 nanoflowers. The comparison between pure and doped samples was carried out to reveal the superior gas sensing performance of hierarchical peony-like Sb-doped SnO2 nanostructures. The experimental result indicated that sensor based on hierarchical peony-like Sb-doped SnO2 nanostructures exhibited excellent formaldehyde sensing properties at lower operating temperature. The effect of Sb-doping on the formaldehyde sensing performance of SnO2 nanostructures has been discussed. The results have provided experimental and theoretical basis for designing high performance gas sensors to detect formaldehyde.

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.

Effect of an Sb-Doped SnO2 Support on the CO-Tolerance of Pt2Ru3 Nanocatalysts for Residential Fuel Cells

We prepared monodisperse Pt2Ru3 nanoparticles supported on carbon black and Sb-doped SnO2 (denoted as Pt2Ru3/CB and Pt2Ru3/Sb-SnO2) with identical alloy composition and particle size distribution by the nanocapsule method. The activities for the hydrogen oxidation reaction (HOR) of these anode catalysts were examined in H2-saturated 0.1 M HClO4 solution in both the presence and absence of carbon monoxide by use of a channel flow electrode at 70 °C. It was found that the CO-tolerant HOR mass activity at 0.02 V versus a reversible hydrogen electrode (RHE) on the Pt2Ru3/Sb-SnO2 electrode was higher than that at the Pt2Ru3/CB electrode in 0.1 M HClO4 solution saturated with 1000 ppm CO (H2-balance). The CO tolerance mechanism of these catalysts was investigated by in situ attenuated total reflection Fourier transform infrared reflection-adsorption spectroscopy (ATR-FTIRAS) in 1% CO/H2-saturated 0.1 M HClO4 solution at 60 °C. It was found, for the Pt2Ru3/Sb-SnO2 catalyst, that the band intensity of CO linearly adsorbed (COL) at step/edge sites was suppressed, together with a blueshift of the COL peak at terrace sites. On this surface, the HOR active sites were concluded to be more available than those on the CB-supported catalyst surface. The observed changes in the adsorption states of CO can be ascribed to an electronic modification effect by the Sb-SnO2 support.