Remarkable promotion effect of trace sulfation on OMS-2 nanorod catalysts for the catalytic combustion of ethanol.
OMS-2 nanorod catalysts were synthesized by a hydrothermal redox reaction method using MnSO4 (OMS-2-SO4) and Mn(CH3COO)2 (OMS-2-AC) as precursors. SO4(2-)-doped OMS-2-AC catalysts with different SO4(2-) concentrations were prepared next by adding (NH4)2SO4 solution into OMS-2-AC samples to investigate the effect of the anion SO4(2-) on the OMS-2-AC catalyst. All catalysts were then tested for the catalytic oxidation of ethanol. The OMS-2-SO4 catalyst synthesized demonstrated much better activity than OMS-2-AC. The SO4(2-) doping greatly influenced the activity of the OMS-2-AC catalyst, with a dramatic promotion of activity for suitable concentration of SO4(2-) (SO4/catalyst=0.5% W/W). The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES), NH3-TPD and H2-TPR techniques. The results showed that the presence of a suitable amount of SO4(2-) species in the OMS-2-AC catalyst could decrease the Mn-O bond strength and also enhance the lattice oxygen and acid site concentrations, which then effectively promoted the catalytic activity of OMS-2-AC toward ethanol oxidation. Thus it was confirmed that the better catalytic performance of OMS-2-SO4 compared to OMS-2-AC is due to the presence of some residual SO4(2-) species in OMS-2-SO4 samples.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: faty_yan@163.com.
Jie
J
Zhang
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: cbzhang@rcees.ac.cn.
Changbin
C
Zhang
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: honghe@rcees.ac.cn.
Hong
H
He
D000085:Acetates / Q000737:chemistry; D000393:Air Pollutants / Q000737:chemistry*; D000397:Air Pollution / Q000517:prevention & control*; D002384:Catalysis; D000431:Ethanol / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry; D013455:Sulfur / Q000737:chemistry
D000085:Acetates; D000393:Air Pollutants; D017895:Manganese Compounds; D010087:Oxides; D013431:Sulfates; D000431:Ethanol; D013455:Sulfur; C039798:manganese sulfate
Catalytic oxidation; Lattice oxygen; Manganese oxide; Octahedral molecular sieves (OMS-2); VOCs