Synthesis and characterization of high-surface area tungsten carbides and application to electrocatalytic hydrogen oxidation

Hara, Yoshinori; Minami, Noriko; Itagaki, Hiroaki

doi:10.1016/j.apcata.2007.02.011

Cited by 87 publications

(56 citation statements)

References 25 publications

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“…Most of the authors have found that the modification of WC with carbon in the form of WC@C nano composites prepared by different method [27e33] further improve the stability as well as electrocatalytic activity where surface carbon on WC nano particles is present. Moreover, the percentage of surface carbon along with positive aspects like enhancement in thermal stability also has a negative effect on electrocatalytic activity of synthesized electrode material [34]. So there is a need to understand the impact of carbon thickness on electrocatalytic activity of carbon coated WC.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of carbon coated tungsten carbide nano powder using hexane as carbon source and its structural, thermal and electrocatalytic properties

Singla

Singh

Pandey

2015

International Journal of Hydrogen Energy

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Section: Introductionmentioning

confidence: 99%

Synthesis of carbon coated tungsten carbide nano powder using hexane as carbon source and its structural, thermal and electrocatalytic properties

Singla

Singh

Pandey

2015

International Journal of Hydrogen Energy

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“…Hara et al 15 reported that the catalyst showed poor catalytic activity for hydrogen oxidation reactions (HORs) due to surface carbon. In the study of ordered macroporous tungsten carbide, Bosco et al 16 showed that surface carbon can stabilize the surface structure of WC, so the activity of methanol oxidation will be improved.…”

Section: 14mentioning

confidence: 99%

Amorphous carbon modified nano-sized tungsten carbide as a gas diffusion electrode catalyst for the oxygen reduction reaction

Liu

Zhai

et al. 2015

RSC Adv.

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a Nanostructured tungsten carbide with high surface area and containing amorphous carbon is prepared by a low temperature combustion synthesis method. The nanostructured tungsten carbide is used as the catalyst in a gas diffusion electrode. The obtained WC with different carbon content was investigated by XRD, FESEM, TG-DTA, BET and XPS. When the molar ratio of C/W is 19/3, the WC particles with different carbon content are obtained after a carbonizing process between 900 and 1400 C, and the content of free carbon in WC also increases gradually with temperature. The carbon content is tested by the high frequency combustion-infrared absorption method in a carbon sulfur analyzer. The electrochemical properties of the tungsten carbide for the oxygen reduction reaction are characterized by its polarization curves and electrochemical impedance. The results show that the presence of the appropriate amorphous carbon is beneficial for improving the conductivity and dispersibility of the tungsten carbide catalyst, and more active centers can be provided by the catalyst.

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“…The catalytic properties of transition metal carbides, particularly those of tungsten and molybdenum, were recognized in pioneering work by Boudart's group [50]. These carbides, and analogous sulfides, have been pursued as substitutes for precious-metal catalysts in reactions requiring hydrogen oxidation/dissociation, such as in fuel cells or water-gas shift reactors [51][52][53][54]. Although they are not necessarily intrinsically hydrogen permeable, dissociated hydrogen readily diffuses along their surfaces.…”

Section: Introductionmentioning

confidence: 99%

Nanoporous, Metal Carbide, Surface Diffusion Membranes for High Temperature Hydrogen Separations

Way¹,

Wolden²

2013

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Colorado School of Mines (CSM) developed high temperature, hydrogen permeable membranes that contain no platinum group metals with the goal of separating hydrogen from gas mixtures representative of gasification of carbon feedstocks such as coal or biomass in order to meet DOE NETL 2015 hydrogen membrane performance targets. We employed a dual synthesis strategy centered on transition metal carbides. In the first approach, novel, high temperature, surface diffusion membranes based on nanoporous Mo 2 C were fabricated on ceramic supports. These were produced in a two step process that consisted of molybdenum oxide deposition followed by thermal carburization. Our best Mo 2 C surface diffusion membrane achieved a pure hydrogen flux of 367 SCFH/ft 2 at a feed pressure of only 20 psig. The highest H 2 /N 2 selectivity obtained with this approach was 4.9. A transport model using "dusty gas" theory was derived to describe the hydrogen transport in the Mo 2 C coated, surface diffusion membranes. The second class of membranes developed were dense metal foils of BCC metals such as vanadium coated with thin (< 60 nm) Mo 2 C catalyst layers. We have fabricated a Mo 2 C/V composite membrane that in pure gas testing delivered a H 2 flux of 238 SCFH/ft 2 at 600 °C and 100 psig, with no detectable He permeance. This exceeds the 2010 DOE Target flux. This flux is 2.8 times that of pure Pd at the same membrane thickness and test conditions and over 79% of the 2015 flux target. In mixed gas testing we achieved a permeate purity of ≥99.99%, satisfying the permeate purity milestone, but the hydrogen permeance was low, ~0.2 SCFH/ft 2 .psi. However, during testing of a Mo 2 C coated Pd alloy membrane with DOE 1 feed gas mixture a hydrogen permeance of >2 SCFH/ft 2 .psi was obtained which was stable during the entire test, meeting the permeance associated with the 2010 DOE target flux. Lastly, the Mo 2 C/V composite membranes were shown to be stable for at least 168 hours = one week, including cycling at high temperature and alternating He/H 2 exposure.4

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Synthesis and characterization of high-surface area tungsten carbides and application to electrocatalytic hydrogen oxidation

Cited by 87 publications

References 25 publications

Synthesis of carbon coated tungsten carbide nano powder using hexane as carbon source and its structural, thermal and electrocatalytic properties

Synthesis of carbon coated tungsten carbide nano powder using hexane as carbon source and its structural, thermal and electrocatalytic properties

Amorphous carbon modified nano-sized tungsten carbide as a gas diffusion electrode catalyst for the oxygen reduction reaction

Nanoporous, Metal Carbide, Surface Diffusion Membranes for High Temperature Hydrogen Separations

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