The promoting effects of La2O3 and CeO2 on K2MoS4/SiO2 catalyst for methanthiol synthesis from syngas blending with H2S

Rare-earth oxides of La2O3 and CeO2 were used as promoters in the preparati on of K2MoS4/SiO2 catalyst for methanthiol synthesis from syngas blending w ith H2S. The experiment results showed that the addition of La2O3 or CeO2 t o K2MoS4/SiO2 was able to improve the catalytic performance in methanthiol synthesis both in activity and selectivity. La2O3 displayed more beneficial effects than CeO2 and the catalyst modified with La2O3 presented a selecti vity of 98.6% for methanthiol. In the catalysts modified with La2O3 or CeO2 , less K2MoS4 decomposed to MoS2 and more to the Mo-S-K phase, which is fav orable and active for methanthiol synthesis, was determined by XRD. XPS res ults revealed that La2O3 was able to protect molybdenum species from deep r eduction and to raise the concentration ratio of Mo6+ to Mo4+ in the cataly sts, and also to depress the formation of (S-S)(2-) species which may induc e the formation of hydrocarbons. (C) 2000 Elsevier Science B.V. All rights reserved.