Enhanced surface Lewis acidity of ZrO2 by –HSO4 for efficient CF4 decomposition†

Abstract

Tetrafluoromethane (CF₄), as the simplest and most abundant perfluorocarbon in the atmosphere, is listed in the ‘United Nations Framework Convention on Gases’ for its strong greenhouse potential. With its increasing atmospheric emissions, catalytic hydrolysis of CF₄ as a non-toxic by-product method has been extensively studied. However, the highly symmetric and inert structure of CF₄ makes it hard to be adsorbed on the catalyst surface. Herein, we developed a protonated sulfate (–HSO₄) modified ZrO₂ (S-ZrO₂) to enhance CF₄ adsorption and achieve its complete decomposition at 650 °C, which was superior to common γ-Al₂O₃. Combining the surface acidity test, in situ infrared spectroscopy and density function theory simulations, we demonstrated that the introduced –HSO₄ effectively enhances the Lewis acidity of adjacent Zr sites, which shows strong CF₄ adsorption ability and promotes its decomposition.