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When superhydrophobic meshes are used for oil/water separation, high flux and high intrusion pressure are usually compromised. Herein, a high-performance superhydrophobic stainless steel mesh membrane with a hairy-like poly(divinylbenzene) (PDVB) coating is fabricated by precipitated cationic polymerization. The synthesis is facile, which is completed in one step at ambient temperature within a short time, i.e., less than 90 s. The unique hair-like microstructure of PDVB is responsible for the superhydrophobic performance with less blockage for the pores. A higher flux for oil is achieved while keeping a high intrusion pressure. Especially, the ellipsoidal pore texture with two sharp tips can give additional high intrusion pressure. In the case of 2800 mesh, the superhydrophobic mesh displays an unprecedentedly high value of up to 22 kPa while maintaining a high flux of 2.0 × 104L·m–2·h–1. The high intrusion pressure enables further increment of flux to 4.2 × 104L·m–2·h–1under a reduced pressure at a higher loading. The current high-performance superhydrophobic mesh realizes higher efficiency in separating oil/water mixtures, which is promising for practical applications, for example, in industrial extraction.

Volatile organic compounds (VOCs), methane, carbon monoxide, soot, automotive exhaust, and nitrogen oxides are harmful to the atmosphere and human health. It is urgent to strictly control their emissions. Heterogeneous catalysis is an effective pathway for the removal of these pollutants, and the critical issue is the development of novel and high-performance catalysts. In this review, we briefly summarize the preparation methods, physicochemical properties, catalytic activities, and related reaction mechanisms for the above pollutants removal of the rare earth oxides, mixed rare earth oxide, rare earth oxide-supported noble metal, and mixed rare earth oxide-supported noble metal catalysts that have been investigated by our group and other researchers. It was found that catalytic performance was associated with the factors, such as specific surface area, pore structure, particle size and dispersion, adsorbed oxygen species concentration, reducibility, reactant activation ability or interaction between metal nanoparticles and support. Furthermore, we also envision the development trend of such a topic in future work.

The strong interaction between Au nanoparticles and support (Au–metal oxide interface) usually governs the performance of a supported Au catalyst in heterogeneous catalysis. In this study, a series of Au/reduced graphene oxide (rGO)/three-dimensionally ordered macroporous (3DOM) Co3O4catalysts with similar textural properties were prepared using the poly(methyl methacrylate)-templating and poly(vinyl alcohol)-protected reduction strategies. It was found that introducing reduced graphene oxide (rGO) as an electron-transfer bridge between Au and 3DOM Co3O4could significantly strengthen the strong metal–support interaction (SMSI), thus enhancing the catalytic activity for CO oxidation. Among all of the catalysts, 1.86 wt % Au/2 wt % rGO/3DOM Co3O4(1.86Au/2rGO/3DOM Co3O4) showed the highest catalytic activity: the CO reaction rate at 40 °C (432.8 μmol/(gAus)) was 2 times higher than that (208.2 μmol/(gAus)) over 1.87Au/3DOM Co3O4. The introduction of rGO could improve the activation of oxygen molecules and hence increase the low-temperature catalytic activity. The strategy for strengthening the SMSI via rGO mediation would guide the designing of highly efficient supported metal catalysts for low-temperature oxidation of CO.

The mesoporous M–Al (M = Ce, La, Co, Ce–La, and Ce–Co) catalysts were synthesized by adopting a modified “one-pot” evaporation-induced self-assembly (EISA) strategy with ultrasound or microwave irradiation. The impact of Au or Pd on the physicochemical property and catalytic performance in toluene combustion was studied in detail. The 0.96 wt % Pd/Ce–Al catalyst prepared with microwave irradiation possessed the highest activity (the temperatures at toluene conversions of 10 and 90% were 209 and 350 °C at a gas hourly space velocity of 40 000 mL/(g h), respectively) and lowest apparent activation energy (100 kJ/mol). We conclude that large surface area, high adsorbed oxygen species concentration, and good low-temperature reducibility accounted for the excellent performance of the 0.96 wt % Pd/Ce–Al catalyst prepared with microwave irradiation.

Ruthenium-based materials are promising catalysts for the removal of chlorine-containing volatile organic compounds (CVOCs) due to their good ability in cleaving the C–Cl bonds and decreasing the Cl deposition. However, the roles of noble bimetals alloyed with Ru have not been clarified clearly. In this work, the bimetallic RuyM (M = Au, Pd or Pt) alloys supported on three-dimensionally ordered macroporous (3DOM) CeO2(xRuyM/3DOM CeO2; RuyM loading (x) = 0.90–0.93 wt%, and Ru/M molar ratio (y) = 2.77–2.87) were fabricated by the polymer microbead-templating and polyvinyl alcohol-protected reduction methods, and their physicochemical properties were well measured using a number of techniques. Oxidation of trichloroethylene (TCE) was used to evaluate catalytic performance of the as-obtained samples with a good-quality 3DOM structure and a surface area of 39–44 m2g−1. The Ru, Pd, and RuyM nanoparticles (NPs) with an average size of 2.9–3.5 nm were uniformly dispersed on the skeleton surface of 3DOM CeO2. The 0.93Ru2.87Pd/3DOM CeO2sample showed the highest catalytic activity and the lowest apparent activation energy (34 kJ mol−1), with the temperatures (T50%and T90%) at TCE conversions of 50 and 90% being 237 and 298 °C at a space velocity of 20 000 mL g−1h−1, respectively. Simultaneously, 0.93Ru2.87Pd/3DOM CeO2exhibited the highest TCE oxidation rate (30.3 μmol gNoblemetal−1s−1) and the highest TOFNoblemetal(3.1 × 10−3s−1) at 250 °C. The 0.93Ru2.87Pd/3DOM CeO2sample also possessed a better hydrothermal stability than the 0.85Ru/3DOM CeO2sample after hydrothermal ageing treatment at 750 °C. Effects of H2O, CO2, and HCl on catalytic activity of 0.93Ru2.87Pd/3DOM CeO2were also examined. The presence of Ru in the samples was favorable for generation of HCl and Cl2and reduction of the by-products in TCE oxidation, and tetrachloroethylene was the main by-product. The possible catalytic mechanism over 0.93Ru2.87Pd/3DOM CeO2was also proposed. The outstanding catalytic efficiency of 0.93Ru2.87Pd/3DOM CeO2could be assigned to the high adsorbed oxygen species, good low-temperature reducibility, strong TCE adsorption and activation ability, and formation of the intimate nanointerface between RuPd NPs and 3DOM CeO2. This work provides a practical guideline for rationally designing the efficient bimetallic catalysts for CVOCs removal under the industrial conditions.

The meso-Co3O4and AgxAuyPd/meso-Co3O4catalysts were prepared using the KIT-6-templating and polyvinyl alcohol-protected NaBH4reduction methods, respectively. Various techniques were used to characterize physicochemical properties of these materials. Catalytic performance of the samples was evaluated for methanol combustion. The cubically crystallized Co3O4support displayed a three-dimensionally ordered mesoporous structure. The supported noble metal nanoparticles (NPs) possessed a surface area of 115−125 m2/g, with the noble NPs (average size = 2.8−4.5 nm) being uniformly dispersed on the surface of meso-Co3O4. Among all of the samples, 0.68 wt% Ag0.75Au1.14Pd/meso-Co3O4showed the highest catalytic activity (T50%= 100 °C and T90%= 112 °C at a space velocity of 80000 mL (g−1h−1). The partial deactivation of the 0.68 wt% Ag0.75Au1.14Pd/meso-Co3O4sample due to water vapor or carbon dioxide introduction was reversible. It is concluded that the good catalytic performance of 0.68 wt% Ag0.75Au1.14Pd/meso-Co3O4was associated with its highly dispersed Ag0.75Au1.14Pd alloy NPs, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Ag0.75Au1.14Pd alloy NPs and meso-Co3O4.

Since the conventional Pd-based catalysts often suffer severe deactivation by water, development of a catalyst with good activity and moisture-resistance ability is of importance in effectively controlling emissions of volatile organic compounds (VOCs). Herein, we report the efficient synthesis of ultrathin palladium–tungsten bimetallic nanosheets with exceptionally high dispersion of tungsten species. The supported catalyst (TiO2/PdW) shows good performance for benzene oxidation, and 90% conversion is achieved at a temperature of 200 °C and a space velocity of 40 000 mL g–1h–1. The TiO2/PdW catalyst also exhibits better water-tolerant ability than the traditional Pd/TiO2catalyst. The high catalytic efficiency can be explained by the facile redox cycle of the active Pd2+/Pd0couple in the close-contact PdOx–WOx–TiO2arrangement. We propose that the reason for good tolerance to water is that the lattice oxygen of the TiO2/PdW catalyst can effectively replenish the oxygen in active PdOxsites consumed by benzene oxidation. A four-step benzene transformation mechanism promoted by the catalyst is proposed. The present work provides a useful idea for the rational design of efficient bimetallic catalysts for the removal of VOCs under the high humidity conditions.

The Pd-based catalysts have been widely studied for the combustion of volatile organic compounds, in which the roles of the Pd and the support are still not known clearly. In this study, mesoporous Co3O4and CoO (i.e., meso-Co3O4and meso-CoO) were prepared and used as support for the loading of Pd nanoparticles (NPs). The supported Pd samples performed much better than the supports for o-xylene combustion, in which the Pd/meso-CoO sample showed the best catalytic activity (T90%= 173 °C), giving rise to reaction rates at 170 °C 3.5 and 84 times higher than those over the Pd/meso-Co3O4and meso-CoO samples, respectively. It has been established that the meso-CoO sample possessed strong ability to activate oxygen molecules to the active oxygen species, the loaded Pd NPs in a metallic Pd phase was beneficial for o-xylene adsorption, and the adsorbed o-xylene species could immediately react with the active oxygen species at the interface between Pd NPs and meso-CoO. Therefore, we conclude that the excellent catalytic performance of the Pd/meso-CoO sample was associated with its highly active Pd–CoO interface.