Xuekuan Li

Presulfidation and activation mechanism of Mo/Al2O3 catalyst sulfided by ammonium thiosulfate

Mo/Al2O3 catalyst was presulfided with (NH4)2S2O3 to elucidate presulfidation and activation mechanism. It is illustrated that the Mo oxide is firstly partially sulfided during presulfidation and then in situ reduced into MoS2−x in activation, and finally sulfided to active state during hydrodesulfurization (HDS). A synergistic effect between the S2− and S6+ ions in (NH4)2S2O3 produces a positive influence on the HDS performance. The S2− ions contribute to the sulfidation of Mo ions, while the S6+ species interact with Al2O3 support, weakening the interaction of active species with support.

The present status of high-pressure research at Beijing Synchrotron Radiation Facility

The present status of high-pressure research at Beijing Synchrotron Radiation Facility is reported. A ten-poles wiggler beamline provides a white beam for investigating samples using a diamond anvil cell. In situ energy-dispersive diffraction is used to determine the pressure-induced phase transitions and equations of state. High pressure can be stably applied by a stepper-motorized loading system with a strain sensor. Some megabar experiments have been carried out without damage on diamonds. Improved beam collimation reduces the background and eliminates gasket scatter. Some research and future developments are also presented.