Efficient Cleavage of C-F Bond via Bridging Hydroxyl Group for FVOCs Hydrolysis-Oxidation

Fluorine-containing volatile organic compound (FVOCs) elimination is urgently desired for protecting the ozone layer and alleviating global warming, but high temperature and catalyst deactivation hinder the development of greener catalytic oxidation. Accurate design of atomic cluster catalysts with special functional sites has been a longstanding challenge. Here, the supported WMo atomic cluster exhibits extraordinarily activity and selectivity for CCl₂F₂ and CF₃CH₂F hydrolysis-oxidation. A series of experiments and AIMD simulation results of H₂O dissociation over the DFT-optimized models of Mo/TiO₂ and WMo/TiO₂ strongly support that the bimetallic atomic catalysts possess a unique "W-OH-Mo" bridging hydroxyl group (OH_B). With the assistance of a considerable number of OH_B at the W-OH-Mo sites, the reaction rate for CCl₂F₂ was 0.174 μmol g^-1 s^-1 at 280 °C, much higher than that over reported catalysts, and CF₃CH₂F elimination reached 85% conversion at a recorded low temperature (480 °C). The significant promotional effect arises from surface OH_B, which promotes the cleavage of the αC-F bond and dehydrofluorination in R134a to form alkene intermediates, thus enabling higher FVOCs conversion and enhanced production of CO₂ and HF. The consumed OH_B was regenerated through the coactivation of O₂ and H₂O at high-concentration oxygen vacancies between neighboring W and Mo atoms. This work opens a promising pathway for developing robust atomic cluster catalysts for environmental catalysis.