Encapsulation metal crystallites

Figure 3.48. An artist impression of possible shapes of catalyst particles present on a support a. spherical particle with only one point contact to support, b. hemispherical particle, strongly bonded to support and partially poisoned, c. metal crystallite, strongly bonded to and partially encapsulated in support, d. complete wetting of the support by the active phase. After Scholten et al, 1985 and Ba.stein cr a/., 1987.

Chemical interactions between metal and support are also observed on main group metal oxides such as Si02, AI2O3, and MgO, which can normally be regarded as chemically highly inert. Strong interactions have also been found between various metals of Groups 8-10 and carbon supports. Palladium and nickel form carbide phases, and the transformation of carbon and the encapsulation of metal crystallites have been proven [18],... 

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