The objective is to determine the rate and mechanism of (1) sulfur poisoning and (2) of regeneration of metal catalysts used in synthesis gas conversion to hydrocarbon products. Auger electron spectroscopy (AES) is used for surface analysis, and in-situ reaction studies of deactivation and regeneration are combined with microreactor studies to quantify sulfur poisoning. An all-glass internal recirculation microreactor has been designed, fabricated, debugged and integrated into a metal-free feed gas and G. C. analysis system for kinetic studies of sulfur deactivation in CO hydrogenation. An UHV antechamber has been designed, built and connected with the Auger electron spectrometer to allow sample treatment at high temperature and pressure with subsequent AES analysis without atmospheric contamination. A gas-dosing, molecular-leak system has been installed on the AES vacuum chamber to allow in-situ sample treatment to bridge the high-pressure low-pressure gap. A mass spectrometer has been added to the system, and a computer is being interfaced with the spectrometer for improved data treatment and analysis at nano-ampere beam currents. The procedures for film preparation and cleaning have been developed; films are being used in all parts of the work.

CO methanantion rates have been measured in the all-glass internal recycle reactor developed for this work. The methanation rate over the cylinder Ni film catalyst at 400/sup 0/C is 3.9 sec/sup -1/ initially, and the catalyst undergoes deactivation to a value of 1.8 sec/sup -1/, comparable with a reported value of 2.5 sec/sup -1/. The activation energy for Ni film on alumina is 24 kcal/mole, that for Ni film on silica is 17.8 kcal/mole comparable to values for Ni on these supports. The kinetics suggest that CO dissociation is rate limiting; carbon on the Ni is easily hydrogenated off. H/sub 2/S causes severe deactivation and regeneration after sulfur poisoning is not easily achieved by oxidation in the reactor. However, sulfur is easily removed from Ni by oxygen from a molecular leak in the high-vacuum chamber of the Auger electron spectrometer. Atmospheric pressure studies using an ante-chamber connected to the spectrometer chamber show that sulfur cannot be removed from Ni under conditions similar to those in the reactor because of rapid oxide growth which buries the sulfur preventing removal. Standards allowing determination of concentration as well as chemical state for Ni, O, S, and C have been developed.