Effect of reduction conditions on electrocatalytic activity of a ternary PtNiCr/C catalyst for methanol electro-oxidation

The effect of reduction conditions on a Pt₂₈Ni₃₆Cr₃₆/C catalyst was investigated by using two different reduction methods: hydrogen reduction and NaBH₄ reduction. In hydrogen reduced catalysts, dissolution of metallic Ni and Cr was observed during cyclic voltammetry (CV) tests, and a larger amount of Ni and Cr was dissolved when reduced at higher temperatures. For methanol electro-oxidation, the highest specific current density of 1.70 A m⁻² at 600 s of the chronoamperometry tests was observed in the catalyst reduced at 300 °C, which was ∼24 times that of a Pt/C catalyst (0.0685 A m⁻²). In NaBH₄ reduced catalysts, formation of an amorphous phase and a more Pt-rich surface was observed in X-ray diffraction and CV results, respectively, with increasing amounts of NaBH₄. When reduced by 50 times of the stoichiometric amount of NaBH₄, the PtNiCr/C catalyst (PtNiCr-50t) showed a current density of 34.1 A g_{noble metal}⁻¹, which was 81% higher than the 18.8 A g_{noble metal}⁻¹ value of a PtRu/C catalyst at 600 s of the chronoamperometry tests. After 13 h of chronoamperometry testing, the activity of the PtNiCr-50t (15.0 A g_{noble metal}⁻¹) was 110% higher than the PtRu/C catalyst (7.15 A g_{noble metal}⁻¹). The PtNiCr/C catalyst shows promise as a Ru-free methanol oxidation catalyst.     

Electrochemical properties of La1−xSrxFeO3 (x = 0.2, 0.4) as negative electrode of Ni-MH batteries

La_(1−x)Sr_xFeO₃ (x = 0.2,0.4) powders were prepared by a stearic acid combustion method, and their phase structure and electrochemical properties were investigated systematically. X-ray diffraction (XRD) analysis shows that La_(1−x)Sr_xFeO₃ perovskite-type oxides consist of single-phase orthorhombic structure (x = 0.2) and rhombohedral one (x = 0.4), respectively. The electrochemical test shows that the reaction at La_(1−x)Sr_xFeO₃ oxide electrodes are reversible. The discharge capacities of La_(1−x)Sr_xFeO₃ oxide electrodes increase as the temperature rises. With the increase of the temperature from 298 K to 333 K, their initial discharge capacity mounts up from 324.4 mA h g⁻¹ to 543.0 mA h g⁻¹ (when x = 0.2) and from 147.0 mA h g⁻¹ to 501.5 mA h g⁻¹ (when x = 0.4) at the current density of 31.25 mA g⁻¹, respectively. After 20 charge-discharge cycles, they still remain perovskite-type structure. Being similar to the relationship between the discharge capacity and the temperature, the electrochemical kinetic analysis indicates that the exchange current density and proton diffusion coefficient of La_(1−x)Sr_xFeO₃ oxide electrodes increase with the increase of the temperature. Compared with La_0.8Sr_0.2FeO₃, La_0.6Sr_0.4FeO₃ electrode is a more promising candidate for electrochemical hydrogen storage because of its higher cycle capacity at various temperatures.     

Ni- and Fe-based catalysts for hydrogen and carbon nanofilament production by catalytic decomposition of methane in a rotary bed reactor

Four catalysts, consisting of Ni, Ni:Cu, Fe or Fe:Mo as the active phase and Al₂O₃ or MgO as a textural promoter, were tested for the catalytic decomposition of methane in a rotary bed reactor, obtaining both CO₂-free hydrogen and carbon nanostructures in a single step. Hydrogen yields of up to 14.4 Ndm³ H₂·(h·g_cat)^− 1 were obtained using the Ni-based catalysts, and methane conversions above 80% were observed with the Fe-based catalysts. In addition to hydrogen production, the Ni-based catalysts allowed the large-scale production of fishbone-like carbon nanofibres, whereas the use of the Fe-based catalysts promoted the production of carbonaceous filaments having a high degree of structural order, consisting of both chain-like carbon nanofibres and carbon nanotubes.     

Ultrafine Amorphous Co–Fe–B Catalysts for the Hydrolysis of NaBH4 Solution to Generate Hydrogen for PEMFC

For hydrogen generation from alkaline sodium borohydride (NaBH₄) solution, Co–Fe–B catalysts with different Co/(Co + Fe) molar ratios (χ_Co) were prepared by the chemical reduction of CoCl₂ and FeCl₃ ethanol solution with KBH₄ solution. The X‐ray diffraction (XRD) and scanning electron microscopy (SEM) analyses revealed that the as‐prepared Co–Fe–B catalysts were in amorphous form and ultrafine. The hydrogen generation measurements showed that as‐prepared Co–B and Co–Fe–B catalysts exhibited excellent catalytic activity. Co–Fe–B with the Co/(Co + Fe) molar ratio (χ_Co) of 0.85 was the best. Its maximum hydrogen generation rate at 298 K was 4,310 mL min^–1 g^–1, while the Co–B was 2,773 mL min^–1 g^–1. The enhanced activity could be attributed to large active surface area, electron transfer from B and Fe to active Co sites, and improvement in the dispersion of Co–B with Fe₂O₃. The activation energy of Co–Fe–B catalyst with the molar ratio χ_Co = 0.85 was decreased to 29.09 kJ mol^–1 as compared to 30.85 kJ mol^–1 obtained with Co–B.     

Methane reforming reaction with carbon dioxide over SBA-15 supported Ni-Mo bimetallic catalysts

A series of mesoporous molecular sieves SBA-15 supported Ni-Mo bimetallic catalysts (xMo1Ni, Ni = 12 wt.%, Mo/Ni atomic ratio = x, x = 0, 0.3, 0.5, 0.7) were prepared using co-impregnation method for carbon dioxide reforming of methane. The catalytic performance of these catalysts was investigated at 800 °C, atmospheric pressure, GHSV of 4000 ml·g_cat^− 1·h^− 1 and a V(CH₄)/(CO₂) ratio of 1 without dilute gas. The result indicated that the Ni-Mo bimetallic catalysts had a little lower initial activity compared with Ni monometallic catalyst, but it kept very stable performance under the reaction conditions. In addition, the Ni-Mo bimetallic catalyst with Mo/Ni atomic ratio of 0.5 showed high activity, superior stability and the lowest carbon deposition rate (0.00073g_c·g_cat^− 1·h^− 1) in 600-h time on stream. The catalysts were characterized by power X-ray diffraction, N₂-physisorption, H₂-TPR, CO₂-TPD, TG and TEM. The results indicate that the Ni-Mo bimetallic catalysts have smaller metal particle, higher metal dispersion, stronger basicity, metal-support interaction and Mo₂C species. It is concluded that Mo species in the Ni-Mo bimetallic catalysts play important roles in reducing effectively the amount of carbon deposition, especially the amount of shell-like carbon deposition.     

Rapid preparation and electrochemical behavior of carbon-coated Li3V2(PO4)3 from wet coordination

An improved solid-state coordination method namely wet coordination has been developed to synthesize carbon-coated monoclinic Li₃V₂(PO₄)₃ rapidly at a low temperature of 600 °C in 1 h. The structure of the sample was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and energy dispersive analysis of X-rays (EDAX). The diffusion coefficient of the lithium ions was measured by cyclic voltammetry (CV). The electrochemical behavior of the sample exhibits a high initial discharge capacity of 130 mAh g⁻¹, which is very close to its theoretical capacity of 132 mAh g⁻¹ under 95 mA g⁻¹ (0.67 C) in the range of 3.3-4.3 V (vs. Li/Li⁺). These results suggest that wet coordination is a promising method for large-scale production of carbon-coated Li₃V₂(PO₄)₃.     

Fast and reversible surface redox reaction of graphene-MnO2 composites as supercapacitor electrodes

We present a quick and easy method to synthesize graphene-MnO₂ composites through the self-limiting deposition of nanoscale MnO₂ on the surface of graphene under microwave irradiation. These nanostructured graphene-MnO₂ hybrid materials are used for investigation of electrochemical behaviors. Graphene-MnO₂ composite (78 wt.% MnO₂) displays the specific capacitance as high as 310 F g⁻¹ at 2 mV s⁻¹ (even 228 F g⁻¹ at 500 mV s⁻¹), which is almost three times higher than that of pure graphene (104 F g⁻¹) and birnessite-type MnO₂ (103 F g⁻¹). Interestingly, the capacitance retention ratio is highly kept over a wide range of scan rates (88% at 100 mV s⁻¹ and 74% at 500 mV s⁻¹). The improved high-rate electrochemical performance may be attributed to the increased electrode conductivity in the presence of graphene network, the increased effective interfacial area between MnO₂ and the electrolyte, as well as the contact area between MnO₂ and graphene.     

Cyclic voltammetry investigation of borohydride oxidation at a gold electrode

Sodium borohydride (NaBH₄) is receiving increasing attention during the last decade regarding its possible application in energy systems. NaBH₄ has the dual potential of generating hydrogen on demand or being directly oxidised in a direct borohydride fuel cell (DBFC). Progress on DBFCs relies on the development of systematic studies to allow a more comprehensive characterisation of the borohydride (BH₄⁻) oxidation process. In this paper, cyclic voltammetry (CV) is applied to study systematically the BH₄⁻ electrooxidation on a gold (Au) disc macroelectrode in 2 mol l⁻¹ NaOH solutions. Voltammograms are obtained for various NaBH₄ concentrations [0.03-0.12 mol l⁻¹], working temperatures [25-65 °C], and potential scan rates [0.02-20 V s⁻¹], over a wide potential range [−1.0-0.8 V vs. SCE]. Modelling of CV data indicates that BH₄⁻ oxidation on Au electrode follows a first irreversible electrochemical pathway via the direct BH₄⁻ oxidation reaction, involving nearly 8 mol of exchanged electrons per mole of BH₄⁻. A second pathway, at higher potentials, concerns a yet undetermined oxidation mechanism in the partially oxidised Au surface which, in a third pathway, is reactivated, allowing an electrochemical-adsorption mechanism to take place. Relevant parameters such as transfer coefficient, kinetic rate constant, standard rate constant, charge transfer activation energy, and number of exchanged electrons are estimated. The BH₄⁻ oxidation reaction on Au is found to be first order with respect to BH₄⁻.     

A novel micro-spherical CoSn2/Sn alloy composite as high capacity anode materials for Li-ion rechargeable batteries

Micro-scaled spherical CoSn₂/Sn alloy powders synthesized from oxides of Sn and Co via carbothermal reduction at 800 °C were examined for use as anode materials in Li-ion battery. The phase composition and particle morphology of the CoSn₂/Sn alloy composite powders were investigated by XRD, SEM and TEM. The prepared CoSn₂/Sn alloy composite electrode exhibits a low initial irreversible capacity of ca. 140 mAh g⁻¹, a high specific capacity of ca. 600 mAh g⁻¹ at constant current density of 50 mA g⁻¹, and a good rate capability. The stable discharge capacities of 500-515 mAh g⁻¹ and the columbic efficiencies of 95.8-98.1% were obtained at current density of 500 mA g⁻¹. The relatively large particle size of CoSn₂/Sn alloy composite powder is apparently favorable for the lowering of initial capacity loss of electrode, while the loose particle structural characteristic and the Co addition in Sn matrix should be responsible for the improvement of cycling stability of CoSn₂/Sn electrode.     

Performance of templated mesoporous carbons in supercapacitors

By analogy with other types of carbons, templated mesoporous carbons (TMCs) can be used as supercapacitors. Their contribution arises essentially from the double layer capacity formed on their surface, which corresponds to 0.14 F m⁻² in aqueous electrolytes such as H₂SO₄ and KOH and 0.06 F m⁻² for the aprotic medium (C₂H₅)₄NBF₄ in CH₃CN. In the case of a series of 27 TMCs, it appears that the effective surface area determined by independent techniques can be as high as 1500-1600 m² g⁻¹, and therefore exceeds the value obtained for many activated carbons (typically 900-1300 m² g⁻¹). On the other hand, the relatively low amount of surface oxygen in the present TMCs, as opposed to activated carbons, reduces the contribution of pseudo-capacitance effects and limits the gravimetric capacitance to 200-220 F g⁻¹ for aqueous electrolytes. In the case of non-aqueous electrolyte, it rarely exceeds 100 F g⁻¹.It is also shown that the average mesopore diameter of these TMCs does not improve significantly the ionic mobility compared with typical activated carbons of pore-widths above 1.0-1.3 nm.This study suggests that activated carbons remain the more promising candidates for supercapacitors with high performances.     

Hydrogen production by oxidative steam reforming of methanol using ceria promoted copper–alumina catalysts

The performance of different Cu/CeO₂/Al₂O₃ catalysts of varying compositions is investigated for the oxidative steam reforming of methanol (OSRM) in order to produce the hydrogen selectively for polymer electrolyte membrane (PEM) fuel cell applications. All the catalysts were prepared by co-precipitation method and characterized for their surface area, pore volume and oxidation–reduction behavior. The effect of various operating parameters studied are as follows: reaction temperature (200–300 °C), contact-time (W/F = 3–15 kg_cat s mol^− 1) and oxygen to methanol (O/M) molar ratio (0–0.5). The steam to methanol (S/M) molar ratio = 1.5 and pressure = 1 atm were kept constant. Among all the catalysts studied, catalyst Cu–Ce–Al:30–20–50 exhibited 100% methanol conversion and 179 mmol s^− 1 kg_cat^− 1 hydrogen production rate at 280 °C with carbon monoxide formation as low as 0.19%. The high catalytic activity and hydrogen selectivity shown by ceria promoted Cu/Al₂O₃ catalysts is attributed to the improved specific surface area, dispersion and reducibility of copper which were confirmed by characterizing the catalysts through temperature programmed reduction (TPR), CO chemisorption, X-ray diffraction (XRD) and N₂ adsorption–desorption studies. Reaction parameters were optimized in order to produce hydrogen with carbon monoxide formation as low as possible. The time-on-stream stability test showed that the Cu/CeO₂/Al₂O₃ catalysts were quite stable.     

Comparative study of CO and CO2 hydrogenation over supported Rh–Fe catalysts

The hydrogenation of CO, CO + CO₂, and CO₂ over titania-supported Rh, Rh–Fe, and Fe catalysts was carried out in a fixed-bed micro-reactor system nominally operating at 543 K, 20 atm, 20 cm³ min^− 1 gas flow (corresponding to a weight hourly space velocity (WHSV) of 8000 cm³ g_cat^− 1 h^− 1), with a H₂:(CO + CO₂) ratio of 1:1. A comparative study of CO and CO₂ hydrogenation shows that while Rh and Rh–Fe/TiO₂ catalysts exhibited appreciable selectivity to ethanol during CO hydrogenation, they functioned primarily as methanation catalysts during CO₂ hydrogenation. The Fe/TiO₂ sample was primarily a reverse water gas shift catalyst. Higher reaction temperatures favored methane formation over alcohol synthesis and reverse water gas shift. The effect of pressure was not significant over the range of 10 to 20 atm.     

EDLC performance of carbide-derived carbons in aprotic and acidic electrolytes

This study shows that carbide-derived carbons (CDCs) with average pore size distributions around 0.9-1 nm and effective surface areas of 1300-1400 m² g⁻¹ provide electrochemical double-layer capacitors with high performances in both aqueous (2M H₂SO₄) and aprotic (1M (C₂H₅)₄NBF₄ in acetonitrile) electrolytes.In the acidic electrolytic solution, the gravimetric capacitance at low current density (1 mA cm⁻²) can exceed 200 F g⁻¹, whereas the volumetric capacitance reaches 90 F cm⁻³. In the aprotic electrolyte they reach 150 F g⁻¹ and 60 F cm⁻³.A detailed comparison of the capacitive behaviour of CDCs at high current density (up to 100 mA cm⁻²) with other microporous and mesoporous carbons indicates better rate capabilities for the present materials in both electrolytes. This is due to the high surface area, the accessible porosity and the relatively low oxygen content.It also appears that the surface-related capacitances of the present CDCs in the aprotic electrolyte are in line with other carbons and show no anomalous behaviour.     

High stability of Ce-promoted Ni/Mg-Al catalysts derived from hydrotalcites in dry reforming of methane

Ce-promoted Ni/Mg-Al catalysts were synthesized by means of a methodology that involves the doping of Ni-Mg-Al mixed oxides derived from hydrotalcites with [Ce(EDTA)]⁻ and subsequent thermal decomposition. The effect of the nominal load of Ce in the catalytic performance of the materials was studied. The solids were characterized by means of XRD, BET area, TPR-H₂, TPD-CO₂, chemical analysis by ICPs, TGA, SEM and TEM and were evaluated in CO₂ reforming of methane at 700 °C. The results indicate the partial reconstruction of the periclase phase during the doping with [Ce(EDTA)]⁻ and the formation of a mixture of crystalline periclase and fluorite phases after the calcination. Catalysts with particle sizes of Ni⁰ between 5 and 9 nm were obtained. Ce presents a promote effect in the degree of reduction of Ni and the amount and strength of the basic sites. It was evident a beneficial effect of cerium in the catalytic activity and selectivity of the doped materials. The increase of the nominal Ce load between 1 and 10% causes no considerable effect in the catalytic activity and selectivity or in the size of crystallite in these materials but in the inhibition of the coke formation. The catalysts show excellent catalytic performance under drastic conditions of reaction and long operation times. The Ce-doped Ni/Mg-Al catalyst is stable up to 100 h of reaction using a feed mixture of CH₄/CO₂/He 10/10/80 at 24 L g⁻¹ h⁻¹, up to 20 h of reaction using CO₂/CH₄ 20/20 at 48 L g⁻¹ h⁻¹ and up to 15 h of reaction using CO₂/CH₄ 40/40 at 96 L g⁻¹ h⁻¹. The filamentous coke formation is demonstrated on the surface of the catalyst when gas of dilution in the reactants is not used. The developed method of synthesis becomes an interesting methodology for obtaining catalysts for CO₂ reforming of methane.     

Effects of complex agents on the anodic deposition and electrochemical characteristics of cobalt oxides

The anodic deposition rate of cobalt oxide from CoCl₂·6H₂O is strongly affected by the type of complex agents (acetate ion (AcO⁻), citrate ion, EDTA) added into the deposition solutions. The oxidation potential of CoCl₂·6H₂O, examined by linear sweep voltammetry (LSV), is negatively shifted from ca. 1.1 V to about 0.8, 0.5, and 0.2 V by adding AcO⁻, citrate ion, and EDTA, respectively. The deposition rate of cobalt oxide is found to depend not only on the coordinating strength between Co and ligands but also on the conversion rate of the Co-L complexes (L: ligand) into the oxy-hydroxyl-Co species after electron transfer. The textural and electrochemical characteristics of resultant Co oxides, examined by X-ray photoelectron spectroscopic (XPS), scanning electron microscopic (SEM), open-circuit potential versus time, and cyclic voltammetric analyses, are also influenced by varying the complex agents. The deposition rate is the highest when the Co oxide is deposited from the precursor solution containing AcO⁻, which also exhibits the highest specific capacitance of ca. 230 F g⁻¹ among all Co oxide deposits (as the oxide loading ≥0.05 mg cm⁻²), demonstrating its most promising applicability in the electrochemical supercapacitors.     

Catalytic filamentous carbon: Structural and textural properties

Catalytic filamentous carbon (CFC) synthesized by the decomposition of methane over iron subgroup metal catalysts (Ni, Co, Fe or their alloys) is a new family of mesoporous carbon materials possessing the unique structural and textural properties. Microstructural properties of CFC (arrangement of the graphite planes in filaments) are shown to depend on the nature of catalyst for methane decomposition. These properties widely vary for different catalysts: the angle between graphite planes and the filament axis can be 0° (Fe-Co-Al₂O₃), 15° (Co-Al₂O₃), 45° (Ni-Al₂O₃), 90° (Ni-Cu-Al₂O₃). The textural properties of CFC depend both on the catalyst nature and the conditions of methane decomposition (T, °C). The micropore volume in CFC is very low, 0.001-0.022 cm³ g⁻¹ at the total pore volume of 0.26-0.59 cm³ g⁻¹. Nevertheless, the BET surface area may reach 318 m² g⁻¹. Results of the TEM (HRTEM), XRD, Raman spectroscopic, SEM and adsorption studies of the structural and textural properties of CFC are discussed.     

Synthesis of sawtooth-like Li4Ti5O12 nanosheets as anode materials for Li-ion batteries

Hierarchical layered hydrous lithium titanate and Li₄Ti₅O₁₂ microspheres assembled by nanosheets have been successfully synthesized via a hydrothermal process and subsequent thermal treatment. The electrochemical properties of the two samples have been investigated by galvanostatic methods. The former, with the obvious layered structure and a large surface area, delivers a reversible capacity of 180 mA h g⁻¹ after 200 cycles at 200 mA g⁻¹. As for Li₄Ti₅O₁₂, with the intriguing and unique sawtooth-like morphology, it presents exceptional high rate performance and excellent cycling stability. Up to 132 mA h g⁻¹ is obtained after 200 cycles at 10,000 mA g⁻¹ (57 C), proving itself promising for high-rate applications.     

Synthesis and characterization of high-density non-spherical Li(Ni1/3Co1/3Mn1/3)O2 cathode material for lithium ion batteries by two-step drying method

Non-spherical Li(Ni_1/3Co_1/3Mn_1/3)O₂ powders have been synthesized using a two-step drying method with 5% excess LiOH at 800 °C for 20 h. The tap-density of the powder obtained is 2.95 g cm⁻³. This value is remarkably higher than that of the Li(Ni_1/3Co_1/3Mn_1/3)O₂ powders obtained by other methods, which range from 1.50 g cm⁻³ to 2.40 g cm⁻³. The precursor and Li(Ni_1/3Co_1/3Mn_1/3)O₂ are characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). XPS studies show that the predominant oxidation states of Ni, Co and Mn in the precursor are 2⁺, 3⁺ and 4⁺, respectively. XRD results show that the Li(Ni_1/3Co_1/3Mn_1/3)O₂ material obtained by the two-step drying method has a well-layered structure with a small amount of cation mixing. SEM confirms that the Li(Ni_1/3Co_1/3Mn_1/3)O₂ particles obtained by this method are uniform. The initial discharge capacity of 167 mAh g⁻¹ is obtained between 3 V and 4.3 V at a current of 0.2 C rate. The capacity of 159 mAh g⁻¹ is retained at the end of 30 charge-discharge cycle with a capacity retention of 95%.     

Highly effective cobalt catalyst for wax production in Fischer-Tropsch synthesis

Fischer-Tropsch synthesis (FTS) was carried out in a fixed bed reactor with a highly effective cobalt catalyst for wax production. The procedure for reducing the inactive cobalt oxide to the active cobalt catalyst was examined by X-ray diffraction (XRD) and temperature-programmed reduction (TPR). The results showed that 300 ml/min H₂ at 350 °C for 16 h was suitable for reducing the inactive Co oxides to active metallic Co sites. In the case of the powder and pellet type cobalt catalysts with a reactant (H₂/CO = 2:1) flow rate of 15 g_cat min L⁻¹, catalyst deactivation occurred as a result of mass transfer limitations of the hydrocarbon and water produced on the catalyst. On the other hand, the pellet type cobalt catalyst with a reactant flow rate of 45 g_cat min L⁻¹ showed activity not only for liquid hydrocarbon (C₅₊) formation but also for gas product (CH₄ and CO₂) formation. In particular, the methane yield reached almost 20% due to heat transfer limitation in the catalyst. Considering the heat and mass transfer limitations in the cobalt catalyst, a Co-foam catalyst with an inner metallic foam frame and an outer cobalt catalyst was developed. SEM-EDS Co-mapping revealed the cobalt atoms to be distributed equally over the surface of the Co-foam catalyst. The Co-foam catalyst was highly selective toward liquid hydrocarbon production and the liquid hydrocarbon productivity at 203 °C was 52.5 ml  h⁻¹, which was higher than that by the Co-pellet. In addition, the chain length probability, α, by the Co-foam catalyst was 0.923 and wax formation was especially favored.     

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.