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The crystal size distribution(CSD)was determined with small angle X-ray scattering technique.Theanticoking property of Ni-catalysts was investigated with the steam reforming of n-heptane in a TG-monitoredflow reactor.The results of this study show that the rate of coking on the supported Ni-catalysts depends main-ly on the percentage content of the large size fraction(25-70nm)of Ni-crystallites,and that the dispersion ofNi-crystallites and the anticoking property of the Ni/α-Al_2O_3 catalysts were promoted obviously by theLa_2O_3-modification method.The variation of the Ni-CSD and the anticoking property of the catalysts were fur-ther tested through different periods of hydrothermal treatment.It is found that the content of the largeNi-crystal size fraction and the coking rate pass correspondingly through a maximum.
The crystal size distribution (CSD) was determined with small angle X-ray scattering technique. The staticoking property of Ni-catalysts was investigated with the steam reforming of n-heptane in a TG-monitored flow reactor. The results of this study show that the rate of coking on the supported Ni-catalysts on main-ly on the percentage content of the large size fraction (25-70 nm) of Ni-crystallites, and that of dispersion of Ni-crystallites and the anticoking property of the Ni / α-Al 2 O 3 catalysts were promoted obviously by the La 2 O 3-modification method. The variation of the Ni-CSD and the anticoking property of the catalysts were fur-ther tested through different periods of hydrothermal treatment. It is found that the content of the large Ni-crystal size fraction and the coking rate pass correspondingly through a maximum.