Single adsorption and co-adsorption of aldehyde molecules over (111) surface of precious metal: A theoretical perspective evaluation.

Density functional theory (DFT) simulation was used to investigate the selective tendency of single adsorption and co-adsorption of volatile organic compounds (VOCs) on the surface of precious metal. In this work, formaldehyde (F), acetaldehyde (A) and n-butyraldehyde (B) were used as the molecule models, and Ag(111) surface was selected as the adsorbent to explore the adsorption mechanism of different systems. It was found that the adsorption models of single F molecule, single A molecule and single B molecule systems were spontaneous chemisorption, and the adsorption distances were short. Among them, Ag(111) surface has the best adsorption effect on single B molecule. While the adsorption performance of F molecule and A molecule system is the best for different aldehydes coexistence systems. Results of charge transfer show that all systems exhibit the large amount of charge transfer during the chemisorption. The calculated recovery time and sensitivity show that the sensitivity of single B molecule system is higher than that of single F molecule system and single A molecule system at higher temperatures, and its recovery time is closer to the reasonable value of industrial production. In general, Ag(111) surface has the potential for the detection of aldehydes at high temperature.