The epoxidation of olefins with H2O2 was performed with a tungsten-containing catalyst. This insoluble catalyst forms soluble active species by the action of H2O2, and when the H2O2 is used up, the catalyst precipitates for easy recycling. Thus, the advantages of both homogeneous and heterogeneous catalysts are combined in one system through reaction-controlled phase transfer of the catalyst. When coupled with the 2-ethylanthraquinone/2-ethylanthrahydroquinone redox process for H2O2 production, O2 can be used for the epoxidation of propylene to propylene oxide with 85% yield based on 2-ethylanthrahydroquinone without any co-products. This approach avoids the problematic co-products normally associated with the industrial production of propylene oxide.

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Cu-SSZ-13 and Cu-SSZ-39, with similar structures, are both highly active and hydrothermally stable in the selective catalytic reduction of NO x with NH3 (NH3-SCR), attracting great attention for applications on diesel vehicles. In this study, it was interestingly found that NO2 has distinct effects on the NO x conversion over Cu-SSZ-13 and Cu-SSZ-39, with an inhibiting effect for Cu-SSZ-13 but a promoting effect for Cu-SSZ-39. The distinct NO2 effects were found to be associated with the differences in the reactivity of surface NH4NO3, a key intermediate for NH3-SCR, on these two Cu-based small-pore zeolites. Cu-SSZ-13 has excellent standard SCR activity, but the reactivity of surface NH4NO3 with NO is relatively low, which would induce the accumulation of NH4NO3 on the surface and thus inhibit NO x conversion. Surface Brønsted acid sites play key roles in the reduction of surface NH4NO3 by NO, and Cu-SSZ-39 showed much higher surface acidity than Cu-SSZ-13. Compared with Cu-SSZ-13, the intrinsic standard SCR activity of Cu-SSZ-39 was lower but NH4NO3 could be reduced by NO rapidly on Cu-SSZ-39, even faster than the reduction of NO by the adsorbed NH3 on Cu active sites; thus, NO x conversion was promoted by NO2 on Cu-SSZ-39. This work provides an improved understanding of fast SCR on Cu-based small-pore zeolites.

The impact of SO2 on Cu-SSZ-39 was firstly investigated, and sulfation mechanism at different temperature was proposed.

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A series of films deposited under different oxygen partial pressures and annealed under different atmospheres were prepared to investigate the role of oxygen vacancies in tuning magnetic properties of Co-doped SnO2 films. The inclusive Co in SnO2 is in the 2+ state and substitutes for the Sn4+ site. Intrinsic room temperature ferromagnetism is observed in all films, which is not carrier mediated, but coexists with the dielectric behavior. A maximum magnetic moment of 2.37 μB∕Co is achieved by vacuum annealing due to the increase and diffusion of oxygen vacancies rather than the improvement of crystallinity of the film, and the magnetic moment decreases considerably after air annealing or increasing the oxygen partial pressure during deposition. The changes of oxygen vacancy concentration and distribution are indirectly demonstrated by the relative shifts of Co 2p3∕2 peaks in XPS spectra. The band gap of Co-doped SnO2 film is larger than that of pure SnO2 film, suggesting the influence of inclusive Co on the electronic states, and further blueshift after annealing is also visible. The F-center model is modified to explain the ferromagnetism in insulating Co-doped SnO2 films.