CO tolerance and CO oxidation at Pt and Pt-Ru anode catalysts in fuel cell with polybenzimidazole-H3PO4 membrane

CO tolerance of H₂-air single cell with phosphoric acid doped polybenzidazole (PA-PBI) membrane was studied in the temperature range 140-180 °C using either dry or humidified fuel. Fuel composition was varied from neat hydrogen to 67% (vol.) H₂-33% CO mixtures. It was found that poisoning by CO of Pt/C and Pt-Ru/C hydrogen oxidation catalysts is mitigated by fuel humidification. Electrochemical hydrogen oxidation at Pt/C and Pt-Ru/C catalysts in the presence of up to 50% CO in dry or humidified H₂-CO mixtures was studied in a cell driven mode at 180 °C. High CO tolerance of Pt/C and Pt-Ru/C catalysts in FC with PA-PBI membrane at 180 °C can be ascribed to combined action of two factors—reduced energy of CO adsorption at high temperature and removal of adsorbed CO from the catalyst surface by oxidation. Rate of electrochemical CO oxidation at Pt/C and Pt-Ru/C catalysts was measured in a cell driven mode in the temperature range 120-180 °C. Electrochemical CO oxidation might proceed via one of the reaction paths—direct electrochemical CO oxidation and water-gas shift reaction at the catalyst surface followed by electrochemical hydrogen oxidation stage. Steady state CO oxidation at Pt-Ru/C catalyst was demonstrated using CO-air single cell with Pt-Ru/C anode. At 180 °C maximum CO-air single cell power density was 17 mW cm⁻² at cell voltage U = 0.18 V.     

Effect of heat treatment on stability of gold particle modified carbon supported Pt-Ru anode catalysts for a direct methanol fuel cell

Carbon supported Au-PtRu (Au-PtRu/C) catalysts were prepared as the anodic catalysts for the direct methanol fuel cell (DMFC). The procedure involved simple deposition of Au particles on a commercial Pt-Ru/C catalyst, followed by heat treatment of the resultant composite catalyst at 125, 175 and 200 °C in a N₂ atmosphere. High-resolution transmission electron microscopy (HR-TEM) measurements indicated that the Au nanoparticles were attached to the surface of the Pt-Ru nanoparticles. We found that the electrocatalytic activity and stability of the Au-PtRu/C catalysts for methanol oxidation is better than that of the PtRu/C catalyst. An enhanced stability of the electrocatalyst is observed and attributable to the promotion of CO oxidation by the Au nanoparticles adsorbed onto the Pt-Ru particles, by weakening the adsorption of CO, which can strongly adsorb to and poison Pt catalyst. XPS results show that Au-PtRu/C catalysts with heat treatment lead to surface segregation of Pt metal and an increase in the oxidation state of Ru, which militates against the dissolution of Ru. We additionally find that Au-PtRu/C catalysts heat-treated at 175 °C exhibit the highest electrocatalytic stability among the catalysts prepared by heat treatment: this observation is explained as due to the attainment of the highest relative concentration of gold and the highest oxidation state of Ru oxides for the catalyst pretreated at this temperature.     

Preparation and oxygen reduction activity of stable RuSex/C catalyst with pyrite structure

Carbon supported RuSe_x (x = 0.35-2) catalysts of controlled stoichiometry and phase are synthesized via precipitating ruthenium nanoparticles on Vulcan XC-72R, then selenizing ruthenium with hydrogen annealing. The competition for Se between solid-state Ru selenization and volatile selenium hydride formation results in RuSe_x nanoparticles with the pyrite structure, the Ru hcp structure, or a mixture of the two. These catalysts are methanol tolerant, and catalytically active toward oxygen reduction reaction (ORR). RuSe_x/C (x ≅ 2) with a pyrite structure, produced at 400 °C, exhibits catalytic activity and stability superior to that of RuSe_x/C with a ruthenium hcp structure or a mixed phase. And this pyrite RuSe_x/C (x ≅ 2) catalyst yields H₂O₂ less than 1.5% in the technically pertinent potential range of 0.4-0.6 V (vs. Ag/AgCl). Its stability is verified in 100 CV cycles, which shows that the catalyst annealed at 400 °C is more enduring in potential cycling over 0.65 V (vs. Ag/AgCl), compared with the RuSe_x/C catalyst annealed at 300 °C and the RuSe_cluster/C reference catalyst prepared by thermolysis of Ru₃(CO)₁₂. After CV cycles, the 400 °C-annealed catalyst still exhibits a higher ORR activity than the other two catalysts.     

Preparation of MnOx/TiO2 ultrafine nanocomposite with large surface area and its enhanced toluene oxidation at low temperature

The TiO₂ support materials were synthesized by a chemical vapor condensation (CVC) method and the subsequent MnO_x/TiO₂ catalysts were prepared by an impregnation method. Catalytic oxidation of toluene on the MnO_x/TiO₂ catalysts was examined with ozone. These catalysts had a smaller particle size (9.1 nm) and a higher surface area (299.5 m² g⁻¹) compared to MnO_x/P25-TiO₂ catalysts. The catalysts show high catalytic activity with the ozone oxidation of toluene even at low temperature. As a result, the synthesized support material by the CVC method gave more active catalyst.     

Au/MnO2–TiO2 catalyst for preferential oxidation of carbon monoxide in hydrogen stream

The catalytic activity of nanosize gold catalysts supported on MnO₂–TiO₂ and prepared by deposition–precipitation method has been investigated for preferential oxidation of carbon monoxide in H₂ stream. The catalysts were characterized by inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, nitrogen sorption, transmission electron microscopy, and X-ray photoelectron spectroscopy. The influence of pH in the preparation process and the amount of MnO₂ loading on the catalytic properties of the Au/MnO₂–TiO₂ catalysts were also studied. Fine dispersion of gold nanoparticles on all the supports was obtained. Especially, Au/MnO₂–TiO₂ with MnO₂/TiO₂ mol ratio of 2:98, showed a mean Au particle size of 2.37 nm. The nanosized support constrained the size of gold. The addition of MnO₂ on Au/TiO₂ catalyst improved the selectivity of CO oxidation without sacrificing CO conversion in hydrogen stream between 50 and 100 °C. This could be attributed to the interactions of gold metal with MnO₂–TiO₂ support and the optimum combination of metallic and electron-deficient gold on the catalyst surface.     

The performances of higher alcohol synthesis over nickel modified K2CO3/MoS2 catalyst

Ni modified K₂CO₃/MoS₂ catalyst was prepared and the performance of higher alcohol synthesis catalyst was investigated under the conditions: T = 280–340 °C, H₂/CO (molar radio) = 2.0, GHSV = 3000 h^− 1, and P = 10.0 MPa. Compared with conventional K₂CO₃/MoS₂ catalyst, Ni/K₂CO₃/MoS₂ catalyst showed higher activity and higher selectivity to C₂⁺OH. The optimum temperature range was 320–340 °C and the maximum space-time yield (STY) of alcohol 0.30 g/ml h was obtained at 320 °C. The selectivity to hydrocarbons over Ni/K₂CO₃/MoS₂ was higher, however, it was close to that of K₂CO₃/MoS₂ catalyst as the temperature increased. The results indicated that nickel was an efficient promoter to improve the activity and selectivity of K₂CO₃/MoS₂ catalyst.     

High-temperature close coupled catalysts Pd/Ce-Zr-M/Al2O3 (M = Y, Ca or Ba) used for the total oxidation of propane

A series of high-temperature close coupled catalysts Pd/Ce-Zr-M/Al₂O₃ (M = Y, Ca or Ba) were prepared by ultrasonic-assisted successive impregnation. The catalysts were subjected to a series of characterization measurements. The results of activity evaluation show that Y is the best promoter for propane total oxidation, especially at the calcination temperature of 1100 °C. It is interesting that although the BET specific surface areas and the dispersion of Pd species decrease, the Y-promoted catalyst calcined at 1100 °C shows higher catalytic activity than the corresponding one calcined at 900 °C and better sulfur-resisting performance. The results of TEM, TPHD and CO chemisorption indicate that Y can remarkably increase the dispersion of Pd species. However, the dispersion is hard to be connected with the activity increase as the calcination temperature is elevated from 900 to 1100 °C. The change of active phases and the interaction between Pd species and the supports may account for the activity enhancement. Combined with XRD, H₂-TPR and O₂-TPD results, it is deduced that the coexistence of metallic Pd and PdO species in the catalysts calcined at 1100 °C may be also favorable to C₃H₈ oxidation. In a word, Pd/Ce-Zr-Y/Al₂O₃ is indeed a promising high-temperature close coupled catalyst applicable to high temperature.     

Ethanol electrooxidation on novel carbon supported Pt/SnOx/C catalysts with varied Pt:Sn ratio

Novel carbon supported Pt/SnO_x/C catalysts with Pt:Sn atomic ratios of 5:5, 6:4, 7:3 and 8:2 were prepared by a modified polyol method and characterized with respect to their structural properties (X-ray diffraction (XRD) and transmission electron microscopy (TEM)), chemical composition (XPS), their electrochemical properties (base voltammetry, CO_ad stripping) and their electrocatalytic activity and selectivity for ethanol oxidation (ethanol oxidation reaction (EOR)). The data show that the Pt/SnO_x/C catalysts are composed of Pt and tin oxide nanoparticles with an average Pt particle diameter of about 2 nm. The steady-state activity of the Pt/SnO_x/C catalysts towards the EOR decreases with tin content at room temperature, but increases at 80 °C. On all Pt/SnO_x/C catalysts, acetic acid and acetaldehyde represent dominant products, CO₂ formation contributes 1-3% for both potentiostatic and potentiodynamic reaction conditions. With increasing potential, the acetaldehyde yield decreases and the acetic acid yield increases. The apparent activation energies of the EOR increase with tin content (19-29 kJ mol⁻¹), but are lower than on Pt/C (32 kJ mol⁻¹). The somewhat better performance of the Pt/SnO_x/C catalysts compared to alloyed PtSn_x/C catalysts is attributed to the presence of both sufficiently large Pt ensembles for ethanol dehydrogenation and C-C bond splitting and of tin oxide for OH generation. Fuel cell measurements performed for comparison largely confirm the results obtained in model studies.     

Plasma-catalytic oxidation of adsorbed toluene with gas circulation

The plasma-catalytic oxidation of adsorbed toluene was investigated using gas circulation with MnO_x and AgO_x catalyst. The experimental results indicated that CO_x yield, CO₂ selectivity and ozone decomposition ability enhanced significantly in presence of catalysts. It was observed that adsorbed toluene could be effectively oxidized to CO₂ in presence of catalysts with gas circulation, probably due to the enhanced utilization of reactive species in the system. Typically, when background gas was oxygen, the CO₂ selectivity of MnO_x/γ-Al₂O₃ and AgO_x/γ-Al₂O₃ catalysts were both close to 100% in 60 min. The results showed that N₂O was generated as a by-product with air background gas.     

Experimental evidence and mechanism of the oxygen storage capacity in MnO2-Ce(1−x)ZrxO2/TiO2 catalyst for low-temperature SCR

The oxygen storage capacity of amorphous CeO₂ and its mechanism were investigated in a Zr-doped MnO_x-CeO₂/TiO₂ catalyst at low temperatures. The oxygen storage capacity of several catalysts was determined by the release of lattice oxygen upon reduction of Ce⁴⁺ to Ce³⁺. We designed a temperature programmed reduction analysis using ammonia gas to measure the amount of lattice oxygen release and identify a decrease in reaction-onset temperature from 136 °C to 75 °C upon doping the catalyst with Zr. Additional reduction was observed in Zr-doped MnO_x-CeO₂/TiO₂ and this was attributed to an increase in temperature sensitivity of thermal vibrations of the first Ce–O coordination shell. The temperature dependence of the thermal vibrations was identified by examining the behavior of the Debye–Waller factor as a function of temperature with fitting the extended X-ray absorption fine structure.     

High catalytic activity of PdOx/MnO2 for CO oxidation and importance of oxidation state of Mn

PdO_x/MnO₂ has been examined as a catalyst for CO oxidation using a conventional flow reactor at reaction temperatures between 50 and 150°C. In the reaction conditions of GHSV (gashourlyspacevelocity) of 1.22 × 10⁵/h and CO concentration of 2000 ppm, PdO_x/MnO₂ showed higher catalytic activity compared with PdO_x/Mn₂O₃, which had been previously reported as an effective catalyst due to the cooperative action of Pd and Mn₂O₃ for this reaction. The reason for higher activity of PdO_x/MnO₂ than PdO_x/Mn₂O₃ has been investigated using TPR (temperatureprogrammed reduction) and XPS studies. TPR showed that PdO_x/MnO₂ could be reduced by CO at much lower temperature than PdO_x/Mn₂O₃. During the experiment of reduction and oxidation, XPS showed that the valence of Mn in the PdO_x/MnO₂ was between 4+ and 3+, which is higher than that of Mn in the PdO_x/Mn₂O₃ catalyst of which the valence has been reported to be between 3+ and 2+. It is known that in this catalyst system the support supplies oxygen onto Pd, where the oxidation occurs with adsorbed CO, and the ability of the support to provide oxygen improves the performance of the catalyst. Therefore, it was concluded that the readiness of MnO₂ to be reduced with maintaining a higher oxidation state showed higher CO oxidation activity than Mn₂O₃ as support for PdO_x.     

An investigation of the activity of coprecipitated gold catalysts for methane oxidation

Coprecipitated Au on transition metal oxide catalysts have been tested for their activity toward methane oxidation. Catalyst activities fall in the order Au/Co₃O₄>Au/NiO> Au/MnO_x> Au/Fe₂O₃ > Au/CeO. The Au/Co₃O₄ catalyst is active just below about 250°C. The catalysts are proposed to have more than one type of reactive site since the supports are also active at higher temperatures. Analysis of spent catalysts with X-ray photoelectron spectroscopy indicates that Au exists in at least two oxidation states on some of them, a reduced state and an oxidized state. The activity for methane oxidation increases with increasing oxidation of Auin the oxidized state.     

The effect of the Ce content on the oxidative dehydrogenation of propane over CrOy-CeO2/γ-Al2O3 catalysts

A series of CrO_y (17.5 wt%)-CeO₂ (X wt%)/γ-Al₂O₃ catalysts (X = 0, 0.5, 2, 5, 8) with various Ce contents were prepared by a wetness impregnation method and were applied to the dehydrogenation of propane to propylene at 550 °C and 0.1 MPa. The prepared catalysts were characterized by BET, H₂-TPR, O₂-TPD, XPS, XRD, SEM-EDS and Raman spectroscopy. Among the prepared catalysts, the 17.5Cr-2Ce/Al catalyst with the largest amount of lattice oxygen exhibited the best catalytic performance for the dehydrogenation of propane to propylene with lattice oxygen. The decreased presence of oxygen defects and reducibility were the factors responsible for the improved dehydrogenation activity of the catalysts. The CeO₂ layer could inhibit the evolution of lattice oxygen (O²⁻) to electrophilic oxygen species (O₂⁻), and the oxygen defects on the catalyst surface were reduced. The inhibited lattice oxygen evolution prevented the deep oxidation of propane or propylene, the average CO_x selectivity decreased from 24.41% (17.5Cr/Al) to 5.71% (17.5Cr-2Ce/Al), and the average propylene selectivity increased from 60.15% (17.5Cr/Al) to 85.05% (17.5Cr-2Ce/Al).     

A CuO-CeO2 Mixed-Oxide Catalyst for CO Clean-Up by Selective Oxidation in Hydrogen-Rich Mixtures

A CuO-CeO₂ mixed-oxide catalyst was shown experimentally to be highly active and selective for the oxidation of CO in hydrogen-rich mixtures, and an attractive alternative to the noble metal catalysts presently used for CO clean-up in hydrogen mixtures for proton-exchange membrane fuel cells (PEMFC). Although the presence of H₂O and CO₂ in the feed decreased the activity and increased the reaction temperature considerably to achieve a given CO conversion with a reactor, the selectivity profile with respect to the conversion remained virtually the same. The effect of H₂O and CO₂ on the reaction was found to increase the required energy for reduction of the active copper species in the redox cycles undergone during the reaction. The catalyst showed a slow, reversible deactivation, but the activity was restored on heating the catalyst at 300 °C, even under an inert flow. At space velocities above 42 g h m^-3, the catalyst reduced the CO content to less than 10 ppm in the temperature range 166-176 °C for a feed of 1% CO, 1% O₂, 50% H₂, 20% H₂O, 13.5% CO₂ and balance He. Hence, with this catalyst it is feasible to clean up the CO in a single-stage reactor with relatively small excess oxygen, which is in contrast to the typical multistage reactor systems using noble metal catalysts.     

A comparative study of the oxidation of CO and CH4 over Au/MOx/Al2O3 catalysts

The activity of Au/Al₂O₃ and Au/MO_x/Al₂O₃ (M=Cr, Mn, Fe, Co, Ni, Cu, and Zn) in low temperature CO oxidation and the oxidation of CH₄ was studied. Generally, addition of MO_x to Au/Al₂O₃ stabilizes small Au particles initially present on the support in heat treatments up to 700°C. All multi-component catalysts show a remarkable enhancement in low temperature CO oxidation compared to the mono-component catalysts. The observed activities are directly related to the average Au particle size, whereas the identity of MO_x is less important. The CH₄ oxidation activity of Au/Al₂O₃ is improved upon addition of MnO_x, FeO_x, CoO_x, and to a lesser extent NiO_x. Measured activities in CH₄ oxidation over Au/MO_x/Al₂O₃ decrease in the following order: CuO_x>MnO_x>CrO_x>FeO_x>CoO_x>NiO_x>ZnO_x. The high activity observed for CuO_x and CrO_x containing catalysts is assigned to the intrinsically high CH₄ oxidation capability of these oxides themselves. For Au/MnO_x/Al₂O₃ a lower apparent activation energy was found than for Au/Al₂O₃ and MnO_x/Al₂O₃, which might point to a promoting effect of MnO_x on Au in the oxidation of CH₄. The results presented support a similar model for both CO and CH₄ oxidation. In this model the reaction takes place at the Au/MO_x perimeter, which is defined as the boundary between Au, MO_x and the gas phase. The reductant, CO or CH₄, is adsorbed on Au, and MO_x is the supplier of O.     

Au/Ce1−xZrxO2 as effective catalysts for low-temperature CO oxidation

The physico-chemical properties and activity of Ce-Zr mixed oxides, CeO₂ and ZrO₂ in CO oxidation have been studied considering both their usefulness as supports for Au nanoparticles and their contribution to the reaction. A series of Ce_1−xZr_xO₂ (x = 0, 0.25, 0.5, 0.75, 1) oxides has been prepared by sol–gel like method and tested in CO oxidation. Highly uniform, nanosized, Ce-Zr solid solutions were obtained. The activity of mixed oxides in CO oxidation was found to be dependent on Ce/Zr molar ratio and related to their reducibility and/or oxygen mobility. CeO₂ and Ce_0.75Zr_0.25O₂, characterized by the cubic crystalline phase show the highest activity in CO oxidation. It suggests that the presence of a cubic crystalline phase in Ce-Zr solid solution improves its catalytic activity in CO oxidation. The relation between the physico-chemical properties of the supports and the catalytic performance of Au/Ce_1−xZr_xO₂ catalysts in CO oxidation reaction has been investigated. Gold was deposited by the direct anionic exchange (DAE) method. The role of the support in the creation of catalytic performance of supported Au nanoparticles in CO oxidation was significant. A direct correlation between activity and catalysts reducibility was observed. Ceria, which is susceptible to the reduction at the lowest temperature, in the presence of highly dispersed Au nanoparticles, appears to be responsible for the activity of the studied catalysts. CeO₂-ZrO₂ mixed oxides are promising supports for Au nanoparticles in CO oxidation whose activity is found to be dependent on Ce/Zr molar ratio.     

Low-temperature preferential oxidation of CO in a hydrogen rich stream (PROX) over Au/TiO2: Thermodynamic study and effect of gold-colloid pH adjustment time on catalytic activity

By simulating CO and H₂ oxidations at thermodynamic equilibrium and studying the catalytic oxidations over Au/TiO₂, preferential oxidation of CO in a H₂ rich stream (PROX) was investigated. During the simulation, at least two cases under different gaseous feeds, H₂/CO/O₂/N₂ = 50/1/0.5/48.5 or 50/1/1/48 (vol.%) were examined under the assumption of an ideal gas and one atmosphere pressure in the reactor. It was found that the addition of 1% O₂ (the latter case) effectively reduced CO concentration to less than 100 ppm in the temperature range between 0 and 90 °C. This range narrowed to between 0 and 50 °C with the addition of 3% H₂O and 15% CO₂ in the feed. The thermodynamic study suggests that 1% CO in a H₂ rich system can be decreased to below 100 ppm within those low temperature ranges, if there is no substantial adsorptions onto the catalyst surface and the reactions rapidly reach equilibrium. During the catalysis reaction study, a well-pH adjusted Au/TiO₂ catalyst was found very active for PROX. CO conversions at the reactor outlet were close to those at equilibrium. Au/TiO₂ used in this work was prepared via deposition-precipitation (DP) method. The influence of gold colloid pH (at 6) adjustment time on gold loading, gold particle size and chloride residue on TiO₂ surface was detected by atomic absorption (AA), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). A pH adjustment time of at least 6 h for the preparation of gold colloids at room temperature was demonstrated to be essential for the high catalytic activity of Au/TiO₂. This was attributed to the smaller gold particle and the less chloride residue on the catalyst surface.     

Titanium-doped alumina for catalytic dehydration of methanol to dimethyl ether at relatively low temperatures

Mesoporous Al-Ti oxide composites with molar %Ti of 3, 5, 10, and 20 as well as pure γ-alumina were prepared using a template-free sol-gel method in the absence of a catalyst. The prepared composites were characterized by powder XRD, FTIR spectroscopy and N₂ adsorption for BET surface area and porosity measurements. The composites and the pure alumina possessed relatively high surface areas, 350-410 m²/g, and high porosities after calcination at 500 °C. FTIR spectroscopy was employed to study the products of the catalytic dehydration of methanol to dimethyl ether, DME, over the prepared catalysts at reaction temperatures between 180 and 300 °C. Compared with pure γ-alumina, the Ti-modified alumina with %Ti < 10 showed higher catalytic activity in the methanol dehydration and better selectivity to DME. Composites with %Ti of 3 and 5 showed the highest activity at relatively lower temperatures than the other catalysts where they showed their highest activity at 190 and 200 °C, respectively. The activity of all studied catalysts slightly decreased as the temperature was raised to 300 °C and dropped considerably when the temperature was decreased to 180 °C. However, the activity of Al-Ti-3 dropped only slightly at both temperatures. The selectivity to DME was dependent on the reaction temperature where 100% DME selectivity was obtained at temperatures ?220 °C and as the temperature was raised to 300 °C, some CH₄ and CO₂ formed on the account of DME.     

Effect of calcination temperature on characteristics of sulfated zirconia and its application as catalyst for isosynthesis

The effect of catalyst calcination temperature (450 °C, 600 °C, and 750 °C) on catalytic performance of synthesized and commercial grade sulfated zirconia catalysts towards isosynthesis was studied. The characteristics of these catalysts were determined by using various techniques including BET surface area, XRD, NH₃- and CO₂-TPD, ESR, and XPS in order to relate the catalytic reactivity with their physical, chemical, and surface properties. It was found that, for both synthesized and commercial sulfated zirconia catalysts, the increase of calcination temperature resulted in the increase of monoclinic phase in sulfated zirconia, and the decrease of acid sites. According to the catalytic reactivity, at high calcination temperature, lower CO conversion, but higher isobutene production selectivity was observed from commercial sulfated zirconia. As for synthesized sulfated zirconia, the isobutene production selectivity slightly decreased with increasing calcination temperature, whereas the CO conversion was maximized at the calcination temperature of 600 °C. We concluded from the study that the difference in the calcination temperatures influenced the catalytic performance, sulfur content, specific surface area, phase composition, the relative intensity of Zr³⁺, and acid-base properties of the catalysts.     

CO tolerance and catalytic activity of Pt/Sn/SnO2 nanowires loaded on a carbon paper

Electrochemical activities and structural features of Pt/Sn catalysts supported by hydrogen-reduced SnO₂ nanowires (SnO₂NW) are studied, using cyclic voltammetry, CO stripping voltammetry, scanning electron microscopy, and X-ray diffraction analysis. The SnO₂NW supports have been grown on a carbon paper which is commercially available for gas diffusion purposes. Partial reduction of SnO₂NW raises the CO tolerance of the Pt/Sn catalyst considerably. The zero-valence tin plays a significant role in lowering the oxidation potential of CO_ads. For a carbon paper electrode loaded with 0.1 mg cm⁻² Pt and 0.4 mg cm⁻² SnO₂NW, a conversion of 54% SnO₂NW into Sn metal (0.17 mg cm⁻²) initiates the CO_ads oxidation reaction at 0.08 V (vs. Ag/AgCl), shifts the peak position by 0.21 V, and maximizes the CO tolerance. Further reduction damages the support structure, reduces the surface area, and deteriorates the catalytic activity. The presence of Sn metal enhances the activities of both methanol and ethanol oxidation, with a more pronounced effect on the oxidation current of ethanol whose optimal value is analogous to those of PtSn/C catalysts reported in literature. In comparison with a commercial PtRu/C catalyst, the optimal Pt/Sn/SnO₂NW/CP exhibits a somewhat inferior activity toward methanol, and a superior activity toward ethanol oxidation.