Thermal desorption of the PO radical from polycrystalline Pt surfaces

The PO radical was detected to desorb from polycrystalline Pt surfaces during the catalytic decomposition of dimethyl methyl phosphonate and trimethyl phosphite above 1100 K using the laser-induced fluorescence technique. The activation energy for the desorption of adsorbed PO radicals, PO(a) → PO(g), was determined to be 59±2 kcal/mol in the temperature range 1100-1350 K at different radical source pressures. The mechanisms for PO production from these two catalytic reactions are briefly discussed.