Rationally Fabricated Ce–Mn@ZrO₂–SO₄^2– Catalyst Boosts the Efficient Destruction of Chlorobenzene with SO₂ Impurity: Synergy of Surface SO₄^2– and Acidic Sites

Abstract

The catalytic deactivation caused by SO₂ impurity remains a great challenge in the efficient destruction of industrial chlorinated volatile organic compounds (CVOCs). Herein, a Ce-Mn@ZrO₂-SO₄^2- catalyst with a Ce-O-Mn active system and ZrO₂-SO₄^2- protective layer was rationally engineered, which exhibits superior activity for chlorobenzene (CB) and SO₂ cotreatment at 228 °C, achieving 90% CB mineralization─over 80% higher than that of the CeO₂ catalyst. In situ characterization and theoretical calculation results reveal that the SO₄^2- groups not only inhibit the adsorption of SO₂ molecules through steric hindrance and electrostatic repulsion but also act as the Brønsted acid sites (BAS) to promote C-Cl cleavage of chlorobenzene (CB) and accelerate the desorption of Cl radicals as inorganic chlorine (HCl and Cl₂). Additionally, the Ce-O-Mn structure accelerates electron transfer between active sites, enhances the strength of Lewis acid sites (LAS), and weakens the lattice oxygen stability to generate oxygen vacancies (O_v). These features collectively result in the excellent chlorine and sulfur resistance of the Ce-Mn@ZrO₂-SO₄^2- catalyst. Compared to CeO₂ and Ce-Mn@ZrO₂, chlorinated and sulfated byproducts respectively decrease by 7.9 and 2.7 times in the presence of 100 ppm SO₂. This study provides a feasible and promising strategy for engineering efficacious non-noble metal catalysts toward CVOCs' deep purification with SO₂ impurity, showcasing substantial economic and environmental benefits.