Oxidative removal of CO within the wide range of concentration for the indoor air purification

摘要

Using the batch reactor equipped with CO and CO_2 gas sensor, CO oxidation over Au catalysts in room air was investigated and compared with Pt catalysts. The curves on logarithm of CO concentration during initial 10 mm was well fitted by straight line, which mean the first order dependence on the CO concentration between 10 and 10,000 ppm. The rate constant value (k) of gold catalyst was ten times or more as large as the platinum catalyst for 1,000 ppm CO, while k greatly got depressed between 100 and 1,000 ppm over the platinum catalyst. Although the strongly adsorbed CO on Pt metal was clearly observed by FTIR during CO oxidation of 100 ppm CO over Pt/Al_2O_3, such strongly adsorbed species on Au was never observed on Au/TiO_2 under the same reaction conditions. These features of Au catalysts are favorable for indoor air purification.