Oxidative regeneration of spent molybdate and tungstate hydrotreating catalysts. Y. Yoshimura et al. Energy and Fuels, March-April 1994, 8(2), 435--445.

Temperature-programmed studies of spent Co/Mo and Ni/W catalysts from hydrotreatment of petroleum vacuum gas oil and coal-derived oil were carried out to investigate structural changes in the metals during oxidation and subsequent sulphidation. Catalytic studies and selectivities were almost recovered by low temperature oxidation, while at higher temperatures there was a slight loss of hydrogenation activity but a large increase in hydrocracking activity. 31 refs.