Electrochemical catalytic activity for the hydrogen oxidation of mesoporous WO3 and WO3/C composites

Cui, Xiangzhi; Zhang, Huanhuan; Dong, Xiaoping; Chen, Hangrong; Zhang, Lingxia; Guo, Limin; Shi, Jianlin

doi:10.1039/b806115g

Cited by 56 publications

(50 citation statements)

References 25 publications

(17 reference statements)

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“…However, a decrease of the peak intensities was observed after 100 CV scans. This is likely due to the decrease in surface area caused by the WO 3 coverage [26].…”

Section: Electrochemical Stability Of Wc-syn and Pt/wc-synmentioning

confidence: 99%

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Nanocrystalline tungsten carbide (WC) synthesis/characterization and its possible application as a PEM fuel cell catalyst support

Zhu

Ignaszak

Song

et al. 2012

Electrochimica Acta

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a b s t r a c tNanocrystalline tungsten carbide (WC) with a high surface area and containing minimal free carbon was synthesized via a polymer route. Its physical properties, including solubility in acid solution, electronic conductivity, and thermal stability, were thoroughly studied at two elevated temperatures: 95• C and 200• C. Compared to commercially available WC, this in-house synthesized WC showed lower solubility in acidic media at 200• C, higher electronic conductivity (comparable to that of carbon black), as well as higher thermal stability. However, this material exhibited low electrochemical stability in acidic media when subjected to potential cycling at potentials larger than 0.7 V vs. RHE, due to the electrooxidation of WC. The major product of WC electrooxidation is WO 3 , which was confirmed by X-ray photon spectroscopy measurements. Pt was uniformly deposited on the high surface area WC to form a 20 wt% of Pt supported catalyst for the oxygen reduction reaction (ORR). The ORR mass activity was then obtained using the rotating disk electrode technique.Crown

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“…However, a decrease of the peak intensities was observed after 100 CV scans. This is likely due to the decrease in surface area caused by the WO 3 coverage [26].…”

Section: Electrochemical Stability Of Wc-syn and Pt/wc-synmentioning

confidence: 99%

“…With the proceeding of CV scan, more and more WC was oxidized into WO 3 , which covered the WC surface, resulting in gradually diminishing of this current. The peaks between 0.1 and 0.4 V vs. RHE could be attributed to the reversible redox process of WO 3 /H x WO 3 in acidic media [24][25][26]:…”

Section: Electrochemical Stability Of Wc-syn and Pt/wc-synmentioning

confidence: 99%

Nanocrystalline tungsten carbide (WC) synthesis/characterization and its possible application as a PEM fuel cell catalyst support

Zhu

Ignaszak

Song

et al. 2012

Electrochimica Acta

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“…Others have attributed the improved performance to an increased electrochemical active surface area (ECSA) of Pt on WO x [25,34,40,41]. The improved CO tolerance for Pt on WO x has been shown in several studies [14,21,27,29,30,40].…”

Section: Introductionmentioning

confidence: 99%

“…At the same time as protons can be incorporated in the WO x structure, they also have a significant mobility which means that WO x functions as a proton conductor under these conditions [13]. The electric conductivity of mesoporous tungsten oxide has been shown to increase by 2-4 orders of magnitude, up to 10 −3 −1 m −1 , upon formation of hydrogen tungsten bronzes [14,15]. Since the hydrogen tungsten bronze formation is dependent on the water content, large variation in conductivity has been reported when varying the relative humidity [7].…”

Section: Introductionmentioning

confidence: 99%

“…Sole tungsten oxide has displayed activity for hydrogen oxidation, which was attributed to high porosity and high surface area [14]. Combined Pt and tungsten oxide based catalysts have been investigated for methanol/ethanol oxidation [18][19][20][21][22][23][24][25], CO oxidation [26][27][28][29][30], hydrogen oxidation [14,[31][32][33][34] as well as oxygen reduction [17,[34][35][36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

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Tungsten oxide in polymer electrolyte fuel cell electrodes—A thin-film model electrode study

Wickman¹,

Wesselmark²,

Lagergren³

et al. 2011

Electrochimica Acta

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a b s t r a c tThin films of WO x and Pt on WO x were evaporated onto the microporous layer of a gas diffusion layer (GDL) and served as model electrodes in the polymer electrolyte fuel cell (PEFC) as well as in liquid electrolyte measurements. In order to study the effects of introducing WO x in PEFC electrodes, precise amounts of WO x (films ranging from 0 to 40 nm) with or without a top layer of Pt (3 nm) were prepared. The structure of the thin-film model electrodes was characterized by scanning electron microscopy and Xray photoelectron spectroscopy prior to the electrochemical investigations. The electrodes were analyzed by cyclic voltammetry and the electrocatalytic activity for hydrogen oxidation reaction (HOR) and CO oxidation was examined. The impact of Nafion in the electrode structure was examined by comparing samples with and without Nafion solution sprayed onto the electrode. Fuel cell measurements showed an increased amount of hydrogen tungsten bronzes formed for increasing WO x thicknesses and that Pt affected the intercalation/deintercalation process, but not the total amount of bronzes. The oxidation of pre-adsorbed CO was shifted to lower potentials for WO x containing electrodes, suggesting that Pt-WO x is a more CO-tolerant catalyst than Pt. For the HOR, Pt on thicker films of WO x showed an increased limiting current, most likely originating from the increased electrochemically active surface area due to proton conductivity and hydrogen permeability in the WO x film. From measurements in liquid electrolyte it was seen that the system behaved very differently compared to the fuel cell measurements. This exemplifies the large differences between the liquid electrolyte and fuel cell systems. The thin-film model electrodes are shown to be a very useful tool to study the effects of introducing new materials in the PEFC catalysts. The fact that a variety of different measurements can be performed with the same electrode structure is a particular strength.

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Ordered Porous Crystalline Transition Metal Oxides

Sadakane

Ueda

2010

Porous Materials

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Electrochemical catalytic activity for the hydrogen oxidation of mesoporous WO3 and WO3/C composites

Cited by 56 publications

References 25 publications

Nanocrystalline tungsten carbide (WC) synthesis/characterization and its possible application as a PEM fuel cell catalyst support

Nanocrystalline tungsten carbide (WC) synthesis/characterization and its possible application as a PEM fuel cell catalyst support

Tungsten oxide in polymer electrolyte fuel cell electrodes—A thin-film model electrode study

Ordered Porous Crystalline Transition Metal Oxides

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