REVERSIBLE HYDROGEN ADSORPTION ON MOS2 STUDIED BY TEMPERATURE-PROGRAMMED DESORPTION AND TEMPERATURE-PROGRAMMED REDUCTION

The adsorption and desorption of hydrogen on MoS2 were studied using a combination of temperature-programmed desorption (TPD) and temperature-programmed reduction (TPR) with a control of the maximum temperature. Reversible hydrogen adsorption was observed in the temperature range of 375-500 K. MoS2 samples reduced in hydrogen at different temperatures behaved distinctively towards reversible hydrogen adsorption. The amount of the reversible hydrogen adsorption decreased when the sample was reduced in hydrogen at the medium temperature of 573-673 K, but its characteristics were not changed. For the sample reduced at high temperature, reversible hydrogen adsorption almost disappeared. In the TPR pattern, a reverse peak corresponding to hydrogen desorption was observed in the 500-673 K range. Based on these facts, the nature of the reversible hydrogen is discussed. The dependence of the reversible hydrogen adsorption on surface structure is also discussed. © 1992.