The Influence of CO2, C3H6, NO, H2, H2O or SO2 on the Low-Temperature Oxidation of CO on a Cobalt-Aluminate Spinel Catalyst (Co1.66Al1.34O4)

• A preparation method for making a high temperature stable monolith catalyst, using a cobalt-rich cobalt-aluminate spinel (Co1.66Al1.34O4) as the active material, is proposed. This catalyst, which is known for being active for CO oxidation at low temperatures, was prepared and characterised by BET, SEM, XRD, XPS and CO-TPD. The catalyst was tested for its capacity to oxidise carbon monoxide using oxygen only and oxygen in combination with other compounds typically present in cold start exhausts from Otto engines, i.e. CO2, C3H6. NO, H2, H2O or SO2. When the catalytic activity was tested with only CO and O-2 present in the feed gas, complete conversion was reached at room temperature. When other compounds were present in the gas mixture, they inhibited the CO oxidation to various degrees. The degree of inhibition for the compounds investigated was found to be: SO2 > H2O > NO = C3H6 > H2 > CO2. The main reason for the loss of activity is suggested to origin from the compounds adsorption and formation of different species on the cobalt oxide surface, which seems to inhibit the reduction and/or re-oxidation process of the metal oxide surface and/or the adsorption of CO.

Ämnesord

NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

Nyckelord

BET

C2H6

catalyst pre-treatment

SEM

low-temperature activity

XRD

NOx

catalytic oxidation of carbon monoxide

SO2

XPS

cold start emissions

H2O

cobalt-aluminate

CO-TPD

CO

H-2

CO2

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