Conclusion

Abstract

In this book we have considered the properties of the surface of transition metals and their oxides, and the main regularities of adsorption and catalysis taking place on these surfaces. The transition elements — whether in homogeneous complexes, isolated ions contained in the solid matrix, or in the metallic form — were shown to be much superior in their chemisorptive and catalytic properties to the nontransition elements. As early as in 1960 ROGINSKIJ [7.1] pointed out that the catalytic qualities of transition elements arise from the fact that the potential of chemical forces U(r) in the bonds formed by d electrons falls off with distance r much more slowly than in the bonds formed by s and p electrons, e.g., the value of dU/dr is smaller. Analysis of the potential diagrams of the catalytic reactions indicates that the extent and diffuseness of d orbitals result in the considerable lowering of activation energy for the catalysis on transition metals as compared with the catalysis on nontransition metals [7.1–3].