Enhanced catalytic reduction of p-nitrophenol on ultrathin MoS₂nanosheets decorated noble-metal nanoparticles

Xiu-Qing Qiao, Zhen-Wei Zhang, Feng-Yu Tian, Dong-Fang, Hou, Zheng-Fang Tian, Dongsheng Li, and Qichun Zhang

ABSTRACT: In this work, ultrathin MoS₂nanosheets (MoS₂NSs) with defect-rich structure were prepared and used as catalysts for the reduction of p-nitropheonol. Also, thanks to the defect sites, noble metal (Au, Ag, Pd, Pt) nanoparticles (NPs) can successfully deposited on the MoS₂NSs via a facile and efficient one-step photochemical reduction process without the assistance of stabilizer. The morphology and crystal structure of as-synthesized materials were characterized by X–ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopic (XPS) and N₂physisorption mearurements. Catalytic results demonstrate that as-prepared MoS₂NSs and noble metal modified MoS₂NSs (NM/MoS₂NSs) effectively catalyze the reduction of p-nitrophenol (p-NP) to p- aminophenol (p-AP) with NaBH₄. The Pd/MoS₂NSs shows the best catalytic performance, exhibiting an apparent rate constant (κapp) of 0.386 min^-1even with moderate chemical stability. Interestingly, the activity of MoS₂NSs is comparable and even higher than previous studied noble metal-based catalysts. Moreover, the good reusability without significant activity loss suggests that MoS₂NSs can be a strong candidate for sustainable chemical catalysis. The origins of the high catalytic activity are also discussed and a probable reaction mechanism is suggested. The present work opens up new opportunities for the future design and fabrications of versatile MoS₂-based composite materials.