Low-pressure methanol oxidation over a Cu(110) surface under stationary conditions: (I) reaction kinetics

The steady-state kinetics of methanol oxidation over Cu(110) have been studied in the 10−7 to 10−3 mbar range. H2, H2O, and CO2 are found in addition to the main product formaldehyde. The reactive sticking coefficient of methanol reaches 0.2. A pronounced hysteresis is observed when the temperature is cycled. Our data indicate the presence of two rate maxima, one at ≈400-520 K and the other at ≈900 K. The amplitude of the low-temperature reactivity peak decreases with increasing total pressure, vanishing beyond 10−3 mbar. High oxygen partial pressures led to a poisoning of the reaction, which was apparently caused by the inhibitory effect of high oxygen coverage on methanol adsorption.