Developing highly dispersed few stacking layer MoS2 nanocatalysts with high exposure of active sites is still a challenge in improving their catalytic activities. Herein, we report a facile strategy for fabricating quasi-single-layer (<3 layers) MoS2/TiO2 nanocatalysts by a novel one-step hydrothermal method using ammonium tetrathiomolybdate (ATM) and P25 (TiO2) as Mo precursor and highly dispersed supporter, respectively. MoS2 nanosheets on MoS2/TiO2 nanocatalysts with the quasi-single layer and slab of less than 10 nm expose maximum active sites of the catalytic anthracene hydrogenation. The results of the catalytic anthracene hydrogenation in slurry-bed reactor show that the quasi-single-layer MoS2/TiO2 nanocatalyst exhibits optimized catalytic hydrogenation performance with the selectivity to deep hydrogenation product (AH8) of 51% and hydrogenation percentage of 41.4%, which were respectively about 5.7 times and twice those of unsupported MoS2 catalyst. The outstanding catalytic activity of anathracene hydrogenation over the resultant quasi-single-layer MoS2/TiO2 can be ascribed to the superior structures of MoS2/TiO2 nanocatalysts. The uniform loading of quasi-single-layer MoS2 nanosheets onto the TiO2 can remarkably enhance the exposure of active sites and effectively avoid the self-aggregation of MoS2 nanosheets.

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Highly active MoS 2 catalysts were developed by tuning the precursors and synthesis solvents to upgrade unconventional feedstocks into light fuels through the slurry-phase hydrogenation reaction. A highly dispersed quasi-single-layer (QSL) MoS 2 nanocatalyst has been synthesized by the solvothermal method with L-cysteine and ethylene glycol as the S precursor and solvent, respectively. The QSL MoS 2 nanocatalyst demonstrates extremely high selectivity to octahydroanthracene of 83.1% and hydrogenation percentage of 54.0% for catalytic anthracene hydrogenation, which are, respectively, 11.4 times and 2.6 times as high as those of bulk MoS 2 catalysts. Moreover, the QSL MoS 2 nanocatalyst exhibits excellent catalytic activities and high catalytic versatility for the slurry-phase hydrogenation of various unconventional feedstocks. The contents of light fractions (gas oil and diesel oil) in the hydrogenation products of coal tar and heavy crude oils from Boscana and Venezuela with the QSL MoS 2 nanocatalyst are as high as 80%, and the conversion of asphaltene hydrogenation can reach much higher than 90%. The excellent catalytic activity of the QSL MoS 2 nanocatalyst may result from its nanostructures including a grain size of 20−30 nm, QSLs of less than 3, and a slab length of 3−7 nm, which benefits to highly expose catalytic active sites and improve its dispersion in the slurry-phase hydrogenation reaction system. This synthesis method can be extended to the design of QSL two-dimensional materials with highly exposed active sites for various catalytic reactions.