Pt Co/meso-MnO : Highly efficient catalysts for low-temperature methanol combustion

Complete Degradation of Gaseous Methanol over Pt/FeOx Catalysts by Normal Temperature Catalytic Ozonation

Normal temperature catalytic ozonation (NTCO) is a promising yet challenging method for the removal of volatile organic compounds (VOCs) because of limited activity of the catalysts at ambient temperature. Here, we report a series of Pt/FeO_x catalysts prepared by the co-precipitation method for NTCO of gaseous methanol. All samples were found to be active and among them, the Pt/FeO_x-400 (calcined at 400 °C) catalyst with a Pt cluster loading of 0.2% exhibited the highest activity, able to completely convert methanol into CO₂ and H₂O at 30 °C. Extensive experimental research suggested that the superior catalytic activity could be attributed to the highly dispersed Pt clusters and an appropriate molar ratio of Pt⁰/Pt²⁺. Furthermore, electron paramagnetic resonance and density functional theory computational studies revealed the mechanism that the Pt/FeO_x-400 catalyst could activate O₃ and water effectively to produce hydroxyl radicals responsible for the catalytic oxidation of methanol. The findings of this work may foster the development of technologies for normal temperature abatement of VOCs with low energy consumption.

Biogenic Pt/CaCO3 Nanocomposite as a Robust Catalyst toward Benzene Oxidation

Fabricating the highly dispersive and stable Pt nanoparticles (NPs) on an economical and environmentally friendly support is of great concern in the field of catalysis. Herein, a waste eggshell was used as the support to prepare supported Pt catalysts through a plant-mediated biosynthesis method, in which the Pt precursor was reduced to Pt NPs by employing Cacumen platycladi (CP) leaf extract. The temperature and atmosphere for thermal treatment of such eggshell-supported Pt catalysts were assessed to understand their effects on catalytic performance toward the oxidation of benzene. The optimal Pt/eggshell-Ar (calcined at 400 °C in Ar) demonstrated that the temperature required for 90% benzene conversion (T_90%) was as low as 178 °C (80 000 mL g^-1 h^-1) and could operate steadily for at least 300 h of onstream reaction. The structure of the catalyst after reaction is much the same as that of the unreacted one. Transmission electron microscopy (TEM), thermogravimetry (TG), and X-ray photoelectron spectroscopy (XPS) results showed that Pt NPs were evenly distributed on the eggshell supports, and the calcination conditions had important influences on the residual CP leaf extract, the average Pt NPs size, and the ratio of Pt⁰/Pt²⁺ over the catalysts. Density functional theory (DFT) calculations indicated that the interactions between Pt NPs and porous CaCO₃ could promote benzene activation adsorbed onto the Pt NPs. In addition, biogenic Pt catalysts were proved to overtake the chemically reduced counterparts in the field of catalytic performance; furthermore, both biogenic and chemically reduced Pt NPs supported on the eggshell demonstrated preferable catalytic activity than that of commercial 5Pt/C (com-Pt/C) catalysts. Collectively, immobilizing biogenic noble metal active components on the eggshell-based support could be a promising approach for the preparation of supported noble metal catalysts with excellent catalytic performance toward catalytic oxidation of volatile organic compounds (VOCs).

3DOM CeO2-supported RuyM (M = Au, Pd, Pt) alloy nanoparticles with improved catalytic activity and chlorine-tolerance in trichloroethylene oxidation

The xRu_yM/3DOM CeO₂ catalysts are prepared using the PMMA-templating and PVA-protected reduction methods. The 0.93Ru_2.87Pd/3DOM CeO₂ exhibited excellent catalytic performance, hydrothermal stability, and chlorine-resistance for trichloroethylene oxidation.