Catalysts for initiating the hydrogen-oxygen reaction at 78 $deg;K

Jennings, Tina; Voge, H. H.; Armstrong, W.

doi:10.1016/0021-9517(72)90133-9

Cited by 12 publications

(3 citation statements)

References 4 publications

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“…Most of the past work has centered on classical catalytic materials such as platinum and nickel but recent interest in the catalysis of the H2 -0^r eaction has brought other materials under Investigation [166][167][168][169][170][171][172][173][174]. Some of the materials being studied are silicon carbide, thorium, platinum, nickel, silver, transition metal carbides, and copper.…”

Section: Heatingmentioning

confidence: 99%

Selected topics on hydrogen fuel

Parrish¹,

Voth²,

Hust³

et al. 1975

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The feasibility of using hydrogen as a fuel will be determined by the availability and cost of hydrogen.This chapter considers techniques and costs of producing gaseous hydrogen along with costs of producing liquid, slush and solid hydrogen. It also examines the potential by-products that could lower the overall cost of using hydrogen.Fossil fuels and water are the two sources of hydrogen. Today most industrial hydrogen is derived from hydrocarbons (mainly natural gas) and costs 10 to 15c/kg to produce. When natural gas costs more than approximately 80c/MBTU, coal becomes a competitive source Vith production costs of 20 to 25c/kg. MBTU = BTU x 10 throughout this chapter.As the fossil fuels are depleted, water will become the principal source of hydrogen.The two most promising means of producing hydrogen from water are electrolysis and thermochemical decomposition. Although electrolysis is an existing technology, it is not cost competitive with other existing processes unless electrical power costs less than 5 mills/ kW-h-exceptions occur in those cases where ultra-high purity and/or small quantities of hydrogen are required. Thermochemical decomposition uses a combination of heat and chemicals to decompose water; the process requires several intermediate steps involving chemical reactions and separations.1.3 COST TO MAKE LIQUID, SLUSH, AND SOLID HYDROGEN FROM GASEOUS HYDROGEN Producing liquid, slush, and solid hydrogen from gaseous hydrogen requires capital investment, energy expense, and operating expense for the liquefier and/or refrigerator.An estimate of these costs can be obtained using information from a survey and correlation of current refrigerator/liquef ier capital costs and energy requirements by Strobridge [15].Liquefaction costs presented herein include the cost of gas purification; however, we are unable to supply a breakdown of purifying costs, as these are proprietary industrial data.

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Section: Heatingmentioning

confidence: 99%

Selected topics on hydrogen fuel

Parrish¹,

Voth²,

Hust³

et al. 1975

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“…However, Pt exhibits higher catalytic activity for H 2 gas combustion than Pd does because the adsorbed H 2 is dissociated and activated on the Pt surface. 15,16 Based on these properties, the Pd-Pt bimetal catalyst is expected to exhibit higher activity than that of single catalysts by synergy effects of H 2 absorption and high catalytic activity.…”

mentioning

confidence: 99%

Preparation of Pd–Pt Co-Loaded TiO₂Thin Films by Sol-Gel Method for Hydrogen Gas Sensing

Yanagida

Makino

Ogaki

et al. 2012

J. Electrochem. Soc.

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Catalytic combustion sensors are widely used for H 2 gas sensing because they use a simple sensing mechanism and have high chemical, thermal, and mechanical durability by virtue of their simple structure. In this study, Pd, Pt, and Pd-Pt-loaded TiO 2 thin films were prepared. Their respective capabilities as H 2 gas combustion sensors were investigated. The TiO 2 thin films were prepared using sol-gel method on a glass substrate. Then Pd and/or Pt was loaded on them using photocatalytic deposition. H 2 gas sensing was assessed at 300 • C by measuring the sample resistance under H 2 gas (3-100%) and air flow conditions. A Pd-Pt step-by-step loaded sample showed higher sensitivity than either a Pd or Pt single-loaded sample for H 2 concentrations of less than 30 vol%. Scanning transmission electron microscopic (STEM) observation revealed its structure: Pt fine particles deposited selectively on the Pd particles pre-deposited on the TiO 2 surface. The large surface area of the catalyst and the synergetic effect of Pd and Pt are expected to contribute to the catalytic activity.Hydrogen gas (H 2 ) is an important material used in chemical industries. Recently H 2 is also valued as a new energy source for fuel cells, a clean power source with high conversion efficiency from chemical to electrical energy. The use of H 2 as an energy source is therefore expected to spread widely, but H 2 is a dangerous gas, possessing a low explosive limit (4%, in air) and high combustion heat (141.9 kJ/g). Therefore, the development and improvement of H 2 gas sensing technologies is necessary to underpin the safe use of H 2 gas. In previous studies, H 2 gas sensors of various types were prepared, incorporating semiconductors, 1 solid electrolytes, 2,3 catalytic combustion, 1 optics, 4,5 surface acoustic waves 6,7 (SAC), etc. In practical utilization, catalytic combustion sensors are widely used because of their simple sensing mechanism and high chemical, thermal, and mechanical durability as a result of their simple structure. Generally, catalytic combustion sensors consist of a porous alumina support and noble metal catalyst dispersed on the support surface. The sensor detects flammable gas by a resistance change caused by heat related to catalytic combustion. 8 In this system, the species of a loaded metal, the catalyst support microstructure, and the dispersed condition of the metal affect the sensor response time, sensitivity, and operation temperature. 9 Bimetallic catalysts have attracted much interest in various fields related to combustion catalysts because their catalytic properties can be prompted and enhanced by changing their compositions and structures. 10-12 Bimetallic catalysts often exhibit higher activity, 11 higher selectivity against the target substance, 12 and a longer lifetime 12 than single metal catalysts do. For H 2 gas combustion sensors, Pd-Pt bimetal catalysts are often used. 13,14 Pd is well known to have large H 2 absorption capacity because it forms palladium hydrate in a H 2 atmosphere. However, Pt exhibi...

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“…εκροφάται εύκολα από την επιφάνεια και παρεμποδίζει την προσρόφηση του NO. Στην περίπτωση χρήσης του υδρογόνου το στάδιο 3 δεν επηρεάζει την κινητική του συστήματος, διότι όπως είναι γνωστό η ετερογενής αναγωγή του οξυγόνου (H2+02/Pd) είναι ταχύτατη και πραγματοποιείται αποτελεσματικά σε πολύ χαμηλές θερμοκρασίες ( < 0 °C )[97]. Το αντίθετο συμβαίνει όταν χρησιμοποιείται CO αντί Η2.…”

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Μελετη Της Καταλυτικης Απονιτρωσης Βιομηχανικων Αεριων Εκπομπων

Παπαμελετιου¹

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Catalysts for initiating the hydrogen-oxygen reaction at 78 $deg;K

Cited by 12 publications

References 4 publications

Selected topics on hydrogen fuel

Selected topics on hydrogen fuel

Preparation of Pd–Pt Co-Loaded TiO₂Thin Films by Sol-Gel Method for Hydrogen Gas Sensing

Μελετη Της Καταλυτικης Απονιτρωσης Βιομηχανικων Αεριων Εκπομπων

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Catalysts for initiating the hydrogen-oxygen reaction at 78 $deg;K

Cited by 12 publications

References 4 publications

Selected topics on hydrogen fuel

Selected topics on hydrogen fuel

Preparation of Pd–Pt Co-Loaded TiO2Thin Films by Sol-Gel Method for Hydrogen Gas Sensing

Μελετη Της Καταλυτικης Απονιτρωσης Βιομηχανικων Αεριων Εκπομπων

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Preparation of Pd–Pt Co-Loaded TiO₂Thin Films by Sol-Gel Method for Hydrogen Gas Sensing