Reaction and surface characterization study of Zn/Cr-based higher-alcohol synthesis catalysts X: Effects of excess promoter loading on surface chemistry

Promoter loading level significantly affects the catalytic behavior of Zn/C r spinel higher alcohol synthesis (HAS) catalysts. In this study a 5.9 wt.% Pd-promoted Zn/Cr spinel with a 5 and 7 wt.% K promoter have been tested a nd compared. At 1500 psig and 400 degrees C, the catalyst containing 5 wt.% K results in the production of slightly more butanol, less methanol and mo re hydrocarbons. Using ion scattering spectroscopy and X-ray photoelectron spectroscopy, differences are found between the two catalyst surfaces which must be responsible for the differences in catalytic behavior.