Ethanol synthesis and water gas shift over bifunctional sulfide catalysts. Technical progress report, March 1993--May 1993

Abstract

During this quarter, a systematic study of the preparation of MOS3,the subsequent decomposition treatment to form MoSz, and the Cs-containing reagents and techniques to achieve surface doping of the MoSz with Cs has been initated. Complete characterization of the samples is being carried out at each stage, beginning with the MoS3 samples and ending with the tested catalysts. The goal of this research is to achieve a high surface area catalyst containing lower quantities of the Cs promoter in a highly dispersed state that is stable during catalytic testing. The results of these studies, along with the catalytic testing results of selected high surface area MoSz and Cs/MoSz catalysts, will be presented in the next quarterly progress report• Using experimental data (high resolution electron spectroscopy for chemical analysis (HR-ESCA)) and computational data (solid state Extended Hiickel (EH) theory) obtained previously, investigation and interpretation of the electronic structure of MoS2 (hexagonal 2H form, indicating 2 MoS2 molecules/unit cell) was carried out since the activation of hydrogen depends on the electronic properties of the catalyst. The theoretical valence band (TVB) of MoS2 was obtained by modification of the density of states (DOS) with appropriate valence shell photoelectron cross-sections for A1K_ radiation. Qualitative agreement between theoretical and experimental MoS z valence bands was obtained after parametrization of the EH input ionization potentials Hi__and Slater-type orbital (STO) double zeta coefficients c__. Theoretical energy dispersion curves, not given here, of two-and three-dimensional MoSz model systems (referred to as 2-D and 3-D MoSz) also compared