High-resolution electron microscopy study of the carbon deposit morphology on nickel catalysts

Abstract HREM (high resolution electron microscopy) was used in the study of the structure of carbon deposits obtained on Ni/Al2O3 and Ni/MgO catalysts during steam reforming of n-butane in the temperature range 673 to 953 K. Three kinds of deposits were found on both catalysts: true filaments, tubes and shells. The forms created and their degree of graphitization depend on the reaction temperature. The shape of the catalyst particles has a strong influence on the arrangement of the carbon layers in the deposits. In connection with the observed forms of the deposits the mechanism of the shape transformation of metal particles is discussed.