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Ni-Na-Y分子筛对CO_2加氢反应显示出高的CO选择性和低活性。本文用EXAFS、FTIR、EPR和XRD对Ni-Na-Y分子筛进行了表征,结果表明,在H_2还原下首先形成小的Ni原子簇,接着在催化反应过程中粒径变大,并从超笼移向外表面。结果还表明,CO选择性的高低取决于分子筛的酸性、Na~+的存在和Ni原子簇的粒径大小。在CO气氛下的预处理将提高其生成CO的活性和选择性。
Ni-Na-Y zeolite shows high CO selectivity and low activity for CO2 hydrogenation. In this paper, Ni-Na-Y zeolites were characterized by EXAFS, FTIR, EPR and XRD. The results show that small Ni clusters are formed under the reduction of H_2, followed by larger size of Ni clusters during the catalytic reaction. Move to the outer surface. The results also show that the degree of CO selectivity depends on the molecular sieve acidity, Na ~ + presence and size of Ni clusters. Pretreatment in a CO atmosphere will increase its activity and selectivity for CO generation.