X-Ray Photoelectron Spectroscopic Studies of Catalysts — Supported Cobalt Catalysts —

Abstract XPS techniques were used to clarify the state of supported cobalt catalysts. In order to characterize Co2+ and Co3+, the spin-orbit splitting of the 2p level, which is considered to be affected by the exchange interaction between the unpaired 3d electrons and 2p electrons, was found to be very useful. The interaction between catalyst and support was investigated. The state of supported cobalt was determined: Co2O3 on SiO2, Co2O3+ CoAl2O4 on γ-Al2O3, and LaCoO3 on La2O3. The order of the strength of the chemical interaction between cobalt and support is as follows: La_2O_3>γ-Al_2O_3>SiO_2. This fact was also confirmed by reduction experiments.