Ordered mesoporous Mg-modified silica to confine MoS2 slabs with high sulfidation and dispersion for higher alcohol synthesis via CO hydrogenation

Abstract

KNiMoS as one of the most promising catalysts for the synthesis of higher alcohols (HA) from syngas but still remains challenge in the trade-off between catalytic activity and selectivity. Herein, a series of Mg-modified mesoporous silica (Mg-MS-x) with tunable morphology and pore size were synthesized by the modified-Stöber method which serve as support for KNiMoS catalysts to confine MoS2 active phases for higher alcohol synthesis (HAS) via CO hydrogenation. The ordered mesoporous Mg-modified silica enable the adjustable structure of MoS2 slabs via confinement effect, and thus enhancing the dispersion and proportion of NiMoS active phases. As a result, KNiMoS/Mg-MS-20 with dominant double-layer MoS2 stacking (∼31.2 %) and proper slab length presents the highest alcohol selectivity of 66.3 %, C2+OH selectivity of 80.5 % in the alcohol and space–time yield (STY) of 91.6 mg g-1h−1 for C2+OH. The connections between HAS performance and the structural property of ordered mesopore confined MoS2 catalysts were also discussed to get insight into the structure-performance relationship. This work proposed a promising route to fabricate ordered mesoporous silica confined KNiMoS with different morphology and pore size, which significantly enhance the selectivity of HA and the ratio of C2+OH/ROH in selective CO hydrogenation.