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The catalysts of cobalt and cerium doped Mn/TiO 2 were tested for low-temperature selective catalytic reduction of NO with NH 3 , and these samples were characterized by XRD, XPS, Raman, H 2 -TPR and NH 3 -TPD methods. The catalytic activity results showed that the NO x conversion was obviously improved by Co and Ce doping. Ternary metal oxide catalyst Mn-Co-Ce/TiO 2 exhibited the highest catalytic activity of 99 % at 423 K. The XRD and Raman analysis indicated formation of MnO 2 or CoMnO 3 phases on Mn/TiO 2 and Mn-Co/TiO 2 . The XPS results demonstrated that the metal cations existed mainly in the form of Mn 4? , Co 2? and Ce 4? , respectively. XPS and H 2 -TPR results supported the presence of Mn-Co mixed oxides. Doping of Ce could enhance dispersion of Mn-Co oxides on the surface. Addition of Co and Ce led to higher surface Mn 4? /Mn 3? ratio, chemisorbed oxygen, acidity and dispersity, which enhanced NH 3 adsorption and oxidation of NO to NO 2 , subsequently, the NO x reduction was accelerated through the Fast SCR reaction. Graphical Abstract

Abstract:A series of Mn-Co/TiO 2 catalysts were prepared by wet impregnation method and evaluated for the oxidation of NO to NO 2 . The effects of Co amounts and calcination temperature on NO oxidation were investigated in detail. The catalytic oxidation ability in the temperature range of 403-473 K was obviously improved by doping cobalt into Mn/TiO 2 . These samples were characterized by nitrogen adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and hydrogen temperature programmed reduction (H 2 -TPR). The results indicated that the formation of dispersed Co 3 O 4¨C oMnO 3 mixed oxides through synergistic interaction between Mn-O and Co-O was directly responsible for the enhanced activities towards NO oxidation at low temperatures. Doping of Co enhanced Mn 4+ formation and increased chemical adsorbed oxygen amounts, which also accelerated NO oxidation.

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Highly active photocatalyst, having certain anti-ionic interfering function, of F, S and Bi doped TiO 2 / Sio 2 was used for the first time to degrade the organic pollutants in acrylonitrile industrial wastewater under natural sunlight. The photocatalyst were prepared and characterized by UV-Vis, XRD, TEM, EDS, Nitrogen physical adsorption and XPS technique. UV-Vis analysis revealed addition of F, S and Bi into the lattice of tio 2 led to the expansion of TiO 2 response in the visible region and hence the efficient separation of charge carrier. The photocatalytic potential of as prepared catalyst to degrade acrylonitrile wastewater under simulated and natural sunlight irradiation was investigated. The extent of degradation of acrylonitrile wastewater was evaluated by chemical oxygen demand (COD cr). COD cr in wastewater decreased from 88.36 to 7.20 mgL −1 via 14 h irradiation of simulated sunlight and achieved regulation discharge by 6 h under natural sunlight, illuminating our photocatalyst effectiveness for refractory industrial wastewater treatment. From TEM results, we found that SiO 2 could disperse the photocatalyst with different component distributions between the surface and the bulk phase that should also be responsible for the light absorption and excellent photocatalytic performance. The XPS analysis confirmed the presence of surface hydroxyl group, oxygen vacancies. Acrylonitrile is considered as a significant industrial chemical, originated by the direct oxidation of propylene with ammonia. It is extensively used for the preparation of synthetic rubber and resin, plastic and acrylic fiber 1,2. Various types of organic pollutants are formed during the production of acrylonitrile 3,4 which has definitely induced serious impact on environmental and public health. Owing to its low bioavailability, high toxicity and mingled composition, acrylonitrile production wastewater has been directed as one type of refractory organic wastewater 5. Therefore, it is necessary to develop a safe and efficient technology for the treatment of acrylonitrile wastewater. Various methods have been reported for the treatment of acrylonitrile wastewater, among those methods photocatalysis acquired much attention over the past decade. Since, photocatalytic reaction under sunlight irradiation is more energy-advantageous, and a lot of researchers have made vast efforts to realize the industrialization of photocatalytic treatment of industrial wastewater under sunlight 6-8. However, there were few successful reports under sunlight because of the complexity of industrial wastewater 9-11. Thus, photocatalytic

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