Chemisorbed Oxygen on the Surface of Catalyst-Improved Cataluminescence Selectivity

It is a critical scientific challenge to improve the selectivity of cataluminescence (CTL). Chemisorbed oxygen on the surface of catalysts is one of the essential factors for catalytic oxidization of gaseous reactant molecules during the CTL process. Therefore, it is necessary to investigate the influence of chemisorbed oxygen on the CTL. There exists different chemisorbed oxygen content on the surface of Y2O3 and its precursor, layered rare-earth yttrium hydroxides (Y-NO3-LRHs). In this work, both of them were employed as catalyst models to catalytically oxidize common volatile organic compounds (VOCs) in order to explore the relationship between chemisorbed oxygen and CTL selectivity. It was found that LRHs demonstrated a superior selectivity toward ethyl ether in comparison with Y2O3. The mechanism study showed that only ethyl ether demonstrated the CTL behavior through the catalytical oxidation into CH3CHO* intermediates on the surface of LRHs, while no CTL emissions occurred for the other VOCs because the insufficient chemisorbed oxygen of LRHs was incapable of oxidizing these VOCs into CO2* intermediates. In addition, the luminescent rare-earth Eu3+ ions were doped in Y-NO3-LRHs to further improve the CTL intensity of ethyl ether through the efficient energy transfer between CH3CHO* intermediates and Eu3+ ions. Our work opens up a new route to improve CTL selectivity by tuning the chemisorbed oxygen on the surface of catalysts, different from the previous strategies of exploiting new solid catalysts or decreasing CTL reaction temperature.