Relation of surface structure to the electrocatalytic activity of tungsten carbide

Journal Article · Thu Jun 30 00:00:00 EDT 1977 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(77)90076-8· OSTI ID:7209224

Ross, Jr, P N; Stonehart, P

The electrocatalytic activities of high surface area tungsten carbides for H/sub 2/ oxidation in acid electrolytes were studied and found to be dependent on the methods of preparation of the carbides. Auger electron spectroscopy and x-ray photoemission spectroscopy were used to determine how the surface compositions and chemical states of surface atoms varied with methods of preparation. Bulk crystallographic structures were determined using x-ray diffraction. Low temperature (700/sup 0/C) carburization of tungstic acid was found to deposit or cause the accumulation of an inert carbon layer over the tungsten carbide. This phenomenon could be minimized by mixing the tungstic acid with 10 w/o NH/sub 4/Cl. The most active carbide was slightly carbon deficient at both the surface and in the bulk, with the carbon deficiency probably replaced by oxygen. This active surface was most easily prepared by carburizing amorphous, white, tungstic acid hydrate. Oxygen substitution for carbon probably occurs during an intermediate state of carbon dissolution in the reduced tungsten metal and is aided by the defect structure in the tungstic acid. The increased activity of the oxygen substituted carbide is due to a reduced interaction of the surface with the electrolyte, resulting from covalent tungsten-oxygen bonding. The absolute activity of active tungsten carbide for the oxidation of pure H/sub 2/ at 25/sup 0/C is four orders of magnitude lower than that for Pt.

• Research Organization: United Technologies Corp., Middletown, CT
• OSTI ID: 7209224
• Journal Information: J. Catal.; (United States), Vol. 48:1-3
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
HYDROGEN
OXIDATION
TUNGSTEN CARBIDES
CATALYTIC EFFECTS
AUGER ELECTRON SPECTROSCOPY
CATALYSIS
CATALYSTS
CHEMICAL STATE
X-RAY SPECTROSCOPY
CARBIDES
CARBON COMPOUNDS
CHEMICAL REACTIONS
CRYOGENIC FLUIDS
ELECTRON SPECTROSCOPY
ELEMENTS
FLUIDS
NONMETALS
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
080101* - Hydrogen- Production- Electrolysis