Promoting C-F Bond Activation for Perfluorinated Compounds Decomposition via Atomically Synergistic Lewis and Brønsted Acid Sites.

Abstract

Catalytic hydrolysis is a sustainable method for the degradation of perfluorinated compounds (PFCs) but is challenged by the high reaction temperatures required to cleave strong C-F bonds. Herein, we developed an innovative C-F activation strategy by constructing synergistic Lewis and Brønsted acid pairs over atomically dispersed Zn-O-Al sites to promote C-F bond activation for decomposition of typical PFCs, CF₄. Density functional theory (DFT) calculations demonstrate tricoordinated Al (Al_III) sites and Zn-OH functional, respectively, as Lewis and Brønsted acid sites over Zn-O-Al, synergistically enhancing the adsorption and decomposition of CF₄. X-ray absorption spectroscopy (XAS), pyridine infrared spectroscopy (Py-IR), and ammonia temperature-programmed desorption (NH₃-TPD) verified the presence of both Al_III and Zn-OH on the atomically dispersed Zn-O-Al sites. CF₄-TPD and in situ infrared spectroscopy confirmed that the Zn-O-Al sites facilitate CF₄ adsorption and C-F bond activation. As a result, the Zn-O-Al sites with synergistic Lewis and Brønsted acid pairs achieved 100% CF₄ decomposition at a low temperature of 560 °C and demonstrated outstanding stability for more than 250 h.