The superior HDS catalyst derived from a new Waugh Co-Mo polyoxometalate via cationic substitution

Abstract

In this paper, the Waugh Co-Mo polyoxometalate (POM) (NH4)6[CoMo9O32] was prepared and cationic substituted to increase the Co/Mo ratio to 0.44 with Mo and Co atoms in a new Waugh Co-Mo POM molecule. The method was verified by X-ray diffraction, X-ray fluorescence, and infrared spectroscopy. Then, two series of Co-Mo hydrodesulfurization (HDS) catalysts were prepared using the Waugh Co-Mo POMs and traditional precursors, respectively. The HDS evaluation results showed the activities of catalysts prepared from the new Waugh Co-Mo POM is higher than the reference catalysts. For the catalyst prepared from the new Waugh Co-Mo POM, the cationic substitution provides a higher Co/Mo ratio and atomic-level proximity between Mo and Co atoms, leading to shorter and less stacked MoS2 nano-particles and more exposure of unsaturated edges and corner sites. In addition, a weak interaction between the new Waugh Co-Mo POM and Al2O3 leads to more CoMoS active phases. Catalysts prepared from the new Waugh Co-Mo POM showed excellent HDS performance, demonstrating the new Waugh Co-Mo POM is a superior precursor to construct the efficient HDS catalyst.