Ultrafine Co-MoS2 monolayer catalyst derived from oil-soluble single-molecule polyoxometalates for slurry phase hydrocracking. (1st May 2022)

• Record Type: Journal Article
• Authors: Chen, Yanfei; Lu, Yukun; Guan, Zekun; Liu, Shoujie; Feng, Chao; Sun, Guangxun; Liang, Jilei; Pan, Yuan; Liu, Chenguang; Liu, Yunqi
• Is Part Of: Fuel. Volume 315(2022)
• Publication Date: 2022-05-01
• Subjects: Co-MoS2 monolayer catalyst -- Single-molecule polyoxometalate -- Slurry phase hydrocracking -- XAFS -- DFT calculation; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2022.123134
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: A single-molecule confinement-sulfurization strategy was proposed to construct ultrafine Co-MoS2 monolayer catalysts, employing oil-soluble POMs as precursors. Well-defined Co2 Mo10 -POMs were introduced for regulating CoMoS sites at atomic scale, exhibiting high intrinsic activities in VR HCK. Highlights: Ultrafine Co-MoS2 monolayer catalysts were controllably fabricated from the oil-soluble polyoxometalate (POM) precursors. The POM anions were encapsulated and confined by organic surfactant cations at single-molecule level. Well-defined Co2 Mo10 POMs were introduced for regulating CoMoS active sites at atomic scale. CoMoS active sites show excellent catalytic performance for slurry phase hydrocracking of vacuum residue. The structures and catalytic mechanisms of CoMoS sites were revealed by coupling XAFS with DFT calculations. Abstract: Herein, a novel single-molecule confinement-sulfurization strategy was proposed to construct ultrafine Co-MoS2 monolayer catalysts by using oil-soluble single-molecule polyoxometalates (POMs), (DODA)6 Co2 Mo10, as precursors. Well-defined Co2 Mo10 -POM, acting as molecular pre-assembling platform, is introduced for the atomically precise construction of bimetallic sites. Highly efficient conversion of VR under severe condition is realized with (DODA)6 Co2 Mo10 . The origin of prominent catalytic performance can be attributed to the in-situ formation of ultrafine single-layered Mo-based nanosheets with abundant exposed CoMoS active sites. By combining synchrotron radiation-based X-ray absorption spectroscopy and density functional theory calculations, we further discover that there is clearly intimate interaction between Mo and Co atoms and the dissociation of molecular hydrogen at CoMoS phases is energetically preferred, leading to remarkable hydrogenation and coke suppression activity. This work highlights an idea on the rational design and targeted synthesis of ultrafine bimetallic catalysts for slurry phase HCK with dramatically synergistic catalysis.