A novel 3DOM Pt/MeO_<i>x</i>–SiO₂ catalyst for the catalytic oxidation of VOCs

In this work, we utilized three-dimensional ordered macroporous (3DOM) SiO₂ and non-noble metal oxides (CeO_<i>x</i>, CoO_<i>x</i> and MnO_<i>x</i>) to confine highly dispersed Pt species. The 3DOM Pt/MeO_<i>x</i>-SiO₂ catalyst was used for the catalytic oxidation of benzene to evaluate its catalytic activity, long-term thermal stability, sulfur resistance, and water resistance. The results verified that the 3DOM Pt/CeO_<i>x</i>-SiO₂ catalyst had superior activity (<i>T</i>₉₀ = 210 °C) and strong sulfur resistance (10 ppm). Interestingly, we observed that the 3DOM Pt/MnO_<i>x</i>-SiO₂ catalyst exhibited poor activity and strong sulfur resistance, while the 3DOM Pt/CoO_<i>x</i>-SiO₂ catalyst exhibited poor sulfur resistance. The comprehensive characterizations results indicated that the activity of the catalysts was ascribed to the interaction of MeO_<i>x</i> and Pt species, and the strong interaction of CeO_<i>x</i> and Pt species was beneficial for improving the dispersion of Pt and enriching the surface acid sites and active oxygen and Pt⁰ species. In contrast, the poor interaction of MnO_<i>x</i>/CoO_<i>x</i> and Pt species was unfavourable for the dispersion of Pt, active oxygen species and the surface acidity of the catalysts. In particular, the poor sulfur resistance of 3DOM Pt/CoO_<i>x</i>-SiO₂ was related to the content of Pt^&+ with a high chemical valence state.