Enhanced sulfur resistance by constructing MnOx–Co3O4 interface on Ni foam in the removal of benzene†

The catalytic degradation of volatile organic compounds (VOCs) in the presence of SO₂ remains an urgent issue for industrial applications. Herein, we constructed an MnO_x–Co₃O₄ interface on Ni foam (Mn_xCo_y–NF catalysts) to improve SO₂ resistance for benzene degradation. The surface decoration of MnO_x on Mn_xCo_y–NF catalysts could generate a Co–Mn interface to tune the redox ability and active oxygen species. The Mn₁Co₁–NF catalyst showed high Co³⁺/Co²⁺ and Mn³⁺/Mn⁴⁺ ratios as well as a high O_latt/O_ads ratio, which are conducive to excellent low-temperature reducibility. Benefiting from abundant interfacial active sites, the Mn₁Co₁–NF catalyst exhibited superior catalytic activity with T₅₀ and T₉₀ values of 259 and 290 °C and SO₂-tolerance for benzene degradation. Results of in situ diffuse reflectance infrared Fourier transform spectroscopy and density functional theory calculation revealed that surface metal sulfate species were preferentially formed on surface Mn sites rather than Co sites, thereby retarding the poisoning of Co–Mn interfacial active sites. Correspondingly, the ring-opening of benzoquinone into maleate species on the Mn₁Co₁–NF catalyst was only slightly inhibited by the introduction of SO₂. This work provides a novel route to design SO₂-resistant catalysts for VOC degradation in practical applications.