Enhanced Catalytic Reduction of <i>p</i>-Nitrophenol on Ultrathin MoS₂ Nanosheets Decorated with Noble Metal Nanoparticles

Abstract

In this work, ultrathin MoS2 nanosheets (MoS2 NSs) 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 be successfully deposited on the MoS2 NSs via a facile and efficient one-step photochemical reduction process without the assistance of a 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 spectroscopy (XPS), and N2 physisorption mearurements. Catalytic results demonstrate that as-prepared MoS2 NSs and noble metal modified MoS2 NSs (NM/MoS2 NSs) effectively catalyze the reduction of p-nitrophenol (p-NP) to p-aminophenol (p-AP) with NaBH4. The Pd/MoS2 NSs shows the best catalytic performance, exhibiting an apparent rate constant (κapp) of 0.386 min–1 even with moderate chemical stability. Interestingly, the activity of MoS2 NSs is comparable to and even higher than previously studied noble metal-based catalysts. Moreover, the good reusability without significant activity loss suggests that MoS2 NSs 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.