An ultra-long stability of lanthanum (La) modified molecular sieve for catalytic degradation of typical sulfur-containing VOCs in a near-real environment

The catalytic degradation of typical sulfur-containing VOCs, ethyl mercaptan (C2H5SH), in a near-real environment remains a challenge task. In this study, an ultra-long stability of 600 h for degradation of C2H5SH was obtained over La doped ZSM-5, and the corresponding catalytic performance, reaction and deactivation mechanism were investigated by a series of ex situ and in situ characterizations. Furthermore, the influence law of other low-carbon mercaptans, such as methyl mercaptan (CH3SH), propyl mercaptan (C3H7SH), and butyl mercaptan (C4H9SH) as well as the moisture on their stability were investigated. The slight deactivation by designed experiment revealed a distinguished reversible moisture-induced deactivation mechanism, where moisture promoted the formation of carbonate related species that covers the active sites, while this deactivation could be recovered by a simple temperature-lifting strategy. This work provides a theoretical guidance for catalytic degradation of mixed sulfur-containing VOCs under the presence of moisture.