Hydrothermal stability of MOx-Ce0.75Zr0.25O2 catalysts for NOx reduction by ammonia
来源期刊：Journal of Rare Earths2013年第12期
论文作者：王敏 司知蠢 陈磊 吴晓东 於俊
文章页码：1148 - 1156
摘 要：Various acidic components（MOx:phosphate,sulfate,tungstate and niobate）were loaded on Ce0.75Zr0.25O2powders by an impregnation method.The as-prepared catalysts were hydrothermally treated at 760 oC for 48 h in air containing 10 vol.%H2O to obtain the aged catalysts.The catalysts were characterized by X-ray diffraction,Fourier transform infrared spectroscopy,H2programmed-reduction,NH3adsorption and deNOx activity measurements.The results showed that,among the catalysts investigated,the phosphated Ce0.75Zr0.25O2catalyst showed the highest hydrothermal stability.The remained high acidity of the phosphated catalyst with moderate redox property helped to maintain the excellent NH3-SCR activity of hydrothermally aged catalyst.Cerium tungstate led to the poor redox property of the tungstated catalyst although the acidity of catalyst was still high.The decomposition of sulfates at temperatures higher than 600°C restrained the usage of sulfated catalysts in high temperature conditions.The overall dehydration of niobate to niobium oxides led to the low acidity of hydrothermally aged Nb2O5-Ce0.75Zr0.25O2catalyst.
王敏1,2，司知蠢2，陈磊3，吴晓东2,3，於俊2,3
1. Department of Applied Physics,Tsinghua University2. Graduate School at Shenzhen,Tsinghua University3. State Key Laboratory of New Ceramics & Fine Process,School of Materials Science and Engineering,Tsinghua University
摘 要：Various acidic components（MOx:phosphate,sulfate,tungstate and niobate）were loaded on Ce0.75Zr0.25O2powders by an impregnation method.The as-prepared catalysts were hydrothermally treated at 760 oC for 48 h in air containing 10 vol.%H2O to obtain the aged catalysts.The catalysts were characterized by X-ray diffraction,Fourier transform infrared spectroscopy,H2programmed-reduction,NH3adsorption and deNOx activity measurements.The results showed that,among the catalysts investigated,the phosphated Ce0.75Zr0.25O2catalyst showed the highest hydrothermal stability.The remained high acidity of the phosphated catalyst with moderate redox property helped to maintain the excellent NH3-SCR activity of hydrothermally aged catalyst.Cerium tungstate led to the poor redox property of the tungstated catalyst although the acidity of catalyst was still high.The decomposition of sulfates at temperatures higher than 600°C restrained the usage of sulfated catalysts in high temperature conditions.The overall dehydration of niobate to niobium oxides led to the low acidity of hydrothermally aged Nb2O5-Ce0.75Zr0.25O2catalyst.
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