Engineering the accessibility of active sites in mixed 1 T-2H MoS2 nanoflowers via NaClO etching for deep hydrodesulfurization of dibenzothiophene

Abstract

A NaClO etching strategy was adopted to engineer the active structure of mixed 1 T-2H MoS₂ nanoflowers and prepare efficient hydrodesulfurization (HDS) catalysts. In the original MoS₂-P catalyst, the 2H-MoS₂ phase was exposed after MoS₂ slabs were etched using NaClO. Sodium ion insertion with high concentrations increased the interlayer spacing of MoS₂ slabs and increased the transformation of 2H-MoS₂ to 1 T-MoS₂ phases. With increase in the concentration of NaClO solution, the proportions of 1 T-MoS₂ in the MoS₂-N-x catalysts initially increased and then decreased. They then reached a maximum when the NaClO concentration was 1.0 mol/L. Owing to the thermodynamic instability of 1 T-MoS₂, the proportions of 1 T-MoS₂ in the sulfided MoS₂-P and MoS₂-N-x catalysts were less than those of the corresponding unsulfided catalysts. However, among sulfided MoS₂-P and MoS₂-N-x catalysts, the sulfided MoS₂-N-1.0 catalyst demonstrated the highest proportion of the 1 T-MoS₂ phase, the best dispersion of the MoS₂ slabs, and the most coordinatively unsaturated sites, thus providing itself with the optimal HDS performance for removing dibenzothiophene.