Magnetic Co-Doped MoS₂ Nanosheets for Efficient Catalysis of Nitroarene Reduction

Co-doped MoS₂ nanosheets have been synthesized through the hydrothermal reaction of ammonium tetrathiomolybdate and hydrazine in the presence of cobalt acetate. These nanosheets exhibit a dominant metallic 1T phase with cobalt ion-activated defective basal planes and S-edges. In addition, the nanosheets are dispersible in polar solvents like water and methanol. With increased active sites, Co-doped MoS₂ nanosheets exhibit exceptional catalytic activity in the reduction of nitroarenes by NaBH₄ with impressive turnover frequencies of 8.4, 3.2, and 20.2 min^-1 for 4-nitrophenol, 4-nitroaniline, and nitrobenzene, respectively. The catalyst is magnetic, enabling its easy separation from the reaction mixture, thus making its recycling and reusability simple and efficient. The enhanced catalytic activity of the Co-doped 1T MoS₂ nanosheets in comparison to that of undoped 1T MoS₂ nanosheets suggests that incorporation of cobalt ions in the MoS₂ lattice is the major reason for the efficiency of the catalyst. The dopant, Co, plays a dual role. In addition to providing active sites where electron transfer is assisted through redox cycling, it renders the nanosheets magnetic, enabling their easy removal from the reaction mixture.