Characterization and Catalytic Activity of Mn-Co/TiO2 Catalysts for NO Oxidation to NO2 at Low Temperature

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.

Spinel‐Type Mixed Oxides for Stable and Selective Partial Oxidation of Benzyl Alcohol

“…Results of Cu doped spinels show that the Cu promotes Mn reduction, due to which a decrease in reduction temperature was observed upon Cu incorporation, giving a broad low‐temperature reduction peak at about 210 °C (Figure S1b in the Supporting Information) . Co doped spinel shows three reduction peaks at 230, 405 and ∼600 °C, first two peaks assigned to reduction of Mn III at surface and in bulk, while high temperature reduction peak at >600 °C attributed to bulk Co III reduction (Figure S1b in the Supporting Information) ,. Results of this study are in agreement with those reported in literature for Cu doped spinels …”

Catalytic combustion of SOFC stack flue gas over CuO and Mn2O3 supported by La0.8Sr0.2Mn0.67Cu0.33O3 perovskite

“…It is speculated that the high oxidation activity of LSMC(p)‐supported catalysts may have originated from both high oxygen‐ion mobility and the different oxidation states of Mn and Cu species in the LSMC(p) from those of CM(s). XPS analysis of CM(s) and LSMC(p) in Figure showed Mn 2p 3/2 peaks at 641.8 eV and 643.3 eV, which correspond to Mn 3+ and Mn 4+ , respectively . CM(s) showed Cu 2p 3/2 peaks at 930.9 eV and 933.5 eV, which correspond to Cu + and Cu 2+ , respectively, whereas LSMC(p) had only Cu 2+ peak at 933.5 eV .…”

Highly Selective Aerobic Oxidation of 5‐Hydroxymethyl Furfural into 2,5‐Diformylfuran over Mn–Co Binary Oxides

“…In addition, the diffraction patterns of Mn 0.25 ‐Co 0.75 ‐O, consisting of only broad peaks, are recognized as Co 3 O 4 thus suggesting the formation of solid solutions between MnO x and Co 3 O 4 . Some reported Mn−Co catalytic systems forming the CoMnO 3 phase have demonstrated enhanced activities for 1,2‐dichlorobenzene combustion and NO oxidation due to a favorable synergetic effect between the manganese and cobalt species ,. Therefore, the dominant phase of CoMnO 3 may possibly also improve the catalytic activity for HMF oxidation.…”