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A series of Ce0.1TiOx, Cu0.1Ox and CumCe0.1-mTiOx (m = 0.01, 0.02, 0.03) catalysts are prepared via a sol-gel method for the selective catalytic reduction (SCR) of NO with NH3. The samples are mainly characterized by X-ray diffraction (XRD), Raman, H2-TPR, NH3-TPD, separated NO/NH3 oxidation, X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to investigate the properties of the catalysts. Among the CumCe0.1-mTiOx (m = 0.01, 0.02, 0.03) catalysts, Cu0.01Ce0.09TiOx displays much better catalytic activity in the range of 170 °C–425 °C (> 90% NO conversion), N2 selectivity and resistance of SO2 and H2O even at high gas hourly space velocity. The XPS results verify that the introduction of Cu leads to a copper species enrichment environment and the formation of more surface Ce3+ and absorbed oxygen (Oα), which are in favor of the oxidation of NO to NO2, enhancing the activity at low temperature. Furthermore, in situ DRIFTS results confirm that the Langmuir-Hinshelwood (L-H) mechanism is predominant in the NH3-SCR process for the Cu0.01Ce0.09TiOx catalyst at 150 °C.

Carbon encapsulated LaFeO3 perovskite composites (LaFeO3@C) were synthesized by a one-pot method and the effects of carbohydrates as carbon precursor on the activity of LaFeO3@C for catalytic transfer hydrogenation (CTH) reactions were investigated. The textural and surface properties (e.g., pore structure, surface acidity and basicity) of LaFeO3@C vary significantly with carbohydrates, which offer a facile route to tailor the sample by simply changing the carbon precursor. LaFeO3@C-M, using maltose as carbon precursor, shows the best catalyst for the CTH of furfural with isopropanol, with conversion and selectivity of 90.3 % and 94.3 %, respectively, owing to the surface La enrichment, rich oxygen functional groups / oxygen vacancy and matched surface acidity-basicity. This sample is also recyclable after post-treatment in N2 atmosphere and can be applied to catalytic hydrogenation of various carbonyl compounds. The current one-step synthesis method provides an efficient way to design carbon-containing composite catalysts with controllable properties for catalytic applications.

A series of Sm-modified SmaMnNi2Ti7Ox (a = 0.1, 0.2, 0.3, 0.4) catalysts were synthesized and showed better NH3-SCR activity than MnNi2Ti7Ox, meanwhile, the Sm0.3MnNi2Ti7Ox sample exhibited much higher low temperature NH3-SCR performance below about 200 °C, and good SO2 and/or H2O durability. The bulk and surface physicochemical properties were measured to investigate the influence of the Sm addition on the activity by various characterization methods including NO/NH3 oxidation, NH3-TPD, H2-TPR, XRD, N2 adsorption-desorption, XPS. The results illustrate that the Sm addition can not only increase the adsorbed NO/NH3 species, BET surface area, surface acid amount, Mn4+ content, surface adsorbed oxygen and the redox ability but also inhibit the generation of ammonium sulfate/bisulfate, which are beneficial to the NH3-SCR activity. Moreover, the in situ diffuse reflectance infrared Fourier transform spectroscopy was applied to analyze the reaction process, which reveals that the NH3-SCR reaction follows both E–R and L-H mechanisms over Sm0.3MnNi2Ti7Ox.

A serial of novel NimCo0.3-mTi0.7Ox (m = 0.05-0.25) mixed-oxide catalysts was synthesized by sol-gel method, and applied for selective catalytic reduction (SCR) of NOx by NH3. Influences of the Ni/Co ratio on the physico-chemical properties and SCR performance were characterized by various analytical techniques, including BET surface area, XRD, XPS, NH3-TPD, H2-TPR and in situ DRIFTS. The Ni0.1Co0.2Ti0.7Ox catalyst shows optimum NH3-SCR activity and excellent N2 selectivity with a broader activity temperature window (210–450 °C), which is associated with the much higher BET surface area, more surface acid amounts and the suitable redox ability derived from the strong interaction between Co and Ni (Co3+ + Ni2+ ↔ Ni3+ + Co2+). In situ DRIFTS results reveal that the formed monodentate nitrate and NH2 species, as main active intermediates, are favor of the NH3-SCR reaction. The existence of H2O mainly restrains Langmuir-Hinshelwood reaction pathway which may be the main cause for the catalyst deactivation.