Enhancing CO Tolerance of Electrocatalysts: Electro-oxidation of CO on WC and Pt-Modified WC

Mellinger, Zachary J.; Weigert, Erich C.; Stottlemyer, Alan L.; Chen, Jingguang G.

doi:10.1149/1.2844209

Cited by 38 publications

(33 citation statements)

References 33 publications

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“…Nevertheless, the large particle size of the commercial WC used in that work induced a large particle size of Pt (7.5 nm), which resulted in low mass MOR activity. Recently, Mellinger et al [26] reported improved CO oxidation activity for Pt/WC catalysts, and the catalysts were stable until 1.2 V in an acidic medium. Nie et al [27] used WC as a promoter of Pt/C for the ORR; a 150 mV more positive onset potential was observed with the Pt-WC/C catalyst than with Pt/C.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Pt/WC/C catalyst for methanol electro-oxidation and oxygen electro-reduction

Jeon

Lee

et al. 2008

Journal of Power Sources

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Section: Introductionmentioning

confidence: 99%

Investigation of Pt/WC/C catalyst for methanol electro-oxidation and oxygen electro-reduction

Jeon

Lee

et al. 2008

Journal of Power Sources

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“…3 is 0.6 V, which is lower than the CO oxidation potential on Pt film and higher than that on WC. 23 This indicates that a portion of the current in Fig. 3 is contributed to oxidation of CO species from methanol electrooxidation from WC on the PtNiPb/WC catalyst.…”

Section: Resultsmentioning

confidence: 91%

Stable PtNiPb/WC Catalyst for Direct Methanol Fuel Cells

Wang

Zuo

Liu

et al. 2009

Electrochem. Solid-State Lett.

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Tungsten carbide ͑WC͒ was prepared by carbothermal synthesis in 900°C. PtNiPb catalysts with homemade WC and XC-72 carbon black as supports, respectively, were prepared. Their performances were tested through cyclic voltammetric, chronoamperometric, and current density-time curves. Electrochemical activity for methanol electro-oxidation of PtNiPb/WC catalyst is evidently higher than that of PtNiPb/C before accelerated durability testing. Its activity is also markedly higher than that of the latter after an accelerated durability test. These results indicate that the WC as a support can improve the activity and stability of PtNiPb catalyst due to usage of WC and its stability in acidic medium.At present, direct methanol fuel cell ͑DMFC͒ performance still cannot meet the demand of broader commercialization. 1,2 Its price is prohibitive. To enhance the activity of catalysts for methanol electro-oxidation and to lower noble metal loading are the main investigation targets. Many studies indicate that alloying Pt with the other metals significantly enhances the catalytic activities and poison tolerance of Pt in comparison to Pt alone. 2-4 PtRu alloy is considered to be the best binary catalyst in DMFCs; however, its activity and durability cannot yet meet DMFC demands. 3 The Ni from the PtNi alloy is not dissolved in the electrolyte in the potential range useful for methanol electro-oxidation. 5 Methanol electrooxidation on PtRuNi/C catalysts has been presented in detail. 6-8 The activities of PtRu/C catalysts are improved markedly due to the Ni additive. To lower noble metal loading, the PtNiPb/C catalyst has been investigated in our previous work and showed a better catalytic activity, less positive onset potential, and a higher CO tolerance than those observed for Pt/C in the case of methanol electro-oxidation. 9 Catalyst surface area loss due to carbon support corrosion and catalyst metal particle dissolution/aggregation is considered to be one of the major contributors. 10 One strategy to lower performance degradation due to carbon corrosion is to explore alternative, more stable support materials. Carbon nanotubes, 11 carbon nanofibers, 12 and carbon aerogel 13 have been used as catalyst supports. Their durability needs further improvement to meet the demands of DMFC support, though some progress has been obtained. Tungsten carbide is more stable than the carbon materials, both under thermal oxidation and electrochemical oxidation conditions. 14 Tungsten carbide ͑WC͒ as a Pt catalyst support for oxygen reduction reaction, 15,16 CO, 17 and methanol oxidation 18,19 has been investigated. WC is active in methanol electro-oxidation and is a promising alternative electrocatalyst. 19 W 2 C also was synthesized and characterized as a Pt catalyst support for methanol electro-oxidation. 20 However, the activity and durability of multialloy catalysts used as support for methanol electro-oxidation have not yet been explored in detail. This research is aimed to improve the activity and durability of alloy catalysts, to lower...

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“…And because of these detrimental results, a growing endeavor has been undertaken by researchers to identify potential applications of core-shell-structured WC@Pt catalysts with monolayer Pt shells in the fields of the hydrogen evolution reaction (HER), the hydrogen oxidation reaction (HOR) and MOR electrocatalysis [376,510,515,519]. In terms of the catalytic activity of core-shell WC@Pt electrocatalysts for MORs, however, surface science experiments have revealed that the CO binding energy of the Pt monolayer on WC is weaker based on the lower surface desorption temperature of CO than Pt [520]. This weaker CO binding energy can subsequently facilitate CO oxidation by using surface -OH species to produce CO 2 , and thereby increase the availability of active sites on the Pt monolayer.…”

Section: Carbides As Corementioning

confidence: 99%

Core–Shell-Structured Low-Platinum Electrocatalysts for Fuel Cell Applications

Wang

Luo

et al. 2018

Electrochem. Energ. Rev.

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Pt-based catalysts are the most efficient catalysts for low-temperature fuel cells. However, commercialization is impeded by prohibitively high costs and scarcity. One of the most effective strategies to reduce Pt loading is to deposit a monolayer or a few layers of Pt over other metal cores to form core-shell-structured electrocatalysts. In core-shell-structured electrocatalysts, the compositions of the core can be divided into five classes: single-precious metallic cores represented by Pd, Ru, and Au; singlenon-precious metallic cores represented by Cu, Ni, Co, and Fe; alloy cores containing 3d, 4d or 5d metals; and carbide and nitride cores. Of these, researchers have found that carbide and nitride cores can yield tremendous advantages over alloy cores in terms of cost and promotional activities of Pt shells. In addition, desirable shells with reasonable thicknesses and compositions have been recognized to play a dominant role in electrocatalytic performances. And recently, researchers have also found that the catalytic activity of core-shell-structured catalysts is dependent on the binding energy of the adsorbents, which is determined by the d-band center of Pt. The shifting of this d-band center in turn is mainly affected by strain and electronic effects, which can be adjusted by adjusting core compositions and shell thicknesses of catalysts. In the development of these core-shell structures, optimal synthesis methods are of primary concern because they directly determine the practical application potential of the resulting electrocatalysts. And in this article, the principles behind core-shell-structured low-Pt electrocatalysts and the developmental progresses of various synthesis methods along with the traits of each type of core and its effects on Pt shell catalytic activities are discussed. In addition, perspectives on this type of catalyst are discussed and future research directions are proposed.

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Enhancing CO Tolerance of Electrocatalysts: Electro-oxidation of CO on WC and Pt-Modified WC

Cited by 38 publications

References 33 publications

Investigation of Pt/WC/C catalyst for methanol electro-oxidation and oxygen electro-reduction

Investigation of Pt/WC/C catalyst for methanol electro-oxidation and oxygen electro-reduction

Stable PtNiPb/WC Catalyst for Direct Methanol Fuel Cells

Core–Shell-Structured Low-Platinum Electrocatalysts for Fuel Cell Applications

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