Hydroxyl-Supply Engineering via Bifunctional Pt−Ga Dual Sites Enables Low-Temperature CF4 Catalytic Hydrolysis

Abstract

Catalytic hydrolysis is an effective route for decomposing perfluorocarbons, yet its efficiency is fundamentally limited by the rapid depletion of surface hydroxyl species required for C−F bond activation. Herein, we reported a bifunctional Pt−Ga dual-site strategy that enables continuous hydroxyl supply and thereby promotes low-temperature CF4 hydrolysis. Structural and spectroscopic analyses confirmed the formation of atomically proximate Pt−Ga dual sites on Al2O3, where Pt facilitates H2O adsorption while Ga promotes its dissociation into reactive hydroxyls. In situ diffuse reflectance infrared Fourier transform spectroscopy revealed that the Pt−Ga dual sites enhanced H2O adsorption and hydroxyl generation by factors of 1.5 and 3.9, respectively, compared to monometallic counterparts. This hydroxyl enrichment markedly strengthened C−F bond activation, as evidenced by a redshift (5 cm−1) in the CF4 vibrational mode. Kinetic analysis further demonstrated that the coupled H2O adsorption−dissociation process maximizes the steady-state coverage of reactive M−OH species. As a result, PtGa/Al2O3 achieved complete CF4 decomposition at a low temperature of 550 °C and maintained ∼80% conversion at 540 °C for 100 h without detectable deactivation, outperforming most reported systems. This work establishes hydroxyl-flux engineering via bifunctional site design as a general strategy for activating inert C−F bonds and advancing the catalytic detoxification of persistent fluorinated pollutants.