Tribochemical decomposition of formic acid on the nascent surfaces of steel formed by scratching

The nascent surfaces of steel were formed by scratching mechanically under high vacuum conditions and adsorption and decomposition of formic acid on the surfaces were carried out at room temperature. The changes in partial pressures of the related compounds were monitored with a quadruple mass spectrometer. The results showed that the chemisorption rate of formic acid on the nascent surfaces was much higher than the formation rate of the reaction products, carbon dioxide and hydrogen. The analyses of adsorption and desorption activities of the compounds on (from) the nascent surfaces showed that the desorption activity of the products were as high as about 20 times the adsorption activity of formic acid. It is proposed that two types of sites might exist on the nascent surfaces. Although the active sites on the nascent surfaces could chemisorb formic acid molecules, only a portion could contribute to the decomposition of formic acid.