Synthesis and photocatalytic properties of nano-MoS2/kaolin composite

A nano-MoS2/kaolin composite was synthesized by calcining a MoS3/kaolin precursor in H2, which was obtained via a quick deposition of MoS3 on kaolin under a strong acidic condition. The obtained nano-MoS2/kaolin composite was characterized using X-ray diffraction spectroscopy, Brunauer–Emmett–Teller (BET) surface area, scanning electron microscopy, high-resolution transmission electron microscopy, thermal analysis, ultraviolet–visible spectroscopy, and Fourier transform infrared spectroscopy. The results show that the composite had a 16 m2/g BET surface area. MoS2 in the composite was composed of layered structures with thickness of ∼5 nm and length of ∼10 nm. The composite contained an intensive absorption at 380–500 nm, which is in the visible light region, and presented a positive catalytic effect on removing methyl orange from the aqueous solution. The catalytic activity of the composite was influenced by the initial concentration of methyl orange, the amount of the catalyst, the pH value, and the degradation temperature. In addition, the composite catalyst could be regenerated and repeatedly used via filtration. The deactivating catalyst could be reactivated after catalytic reaction by heating at 450 °C for 30 min in H2. The kaolin can decrease the sizes of nano-MoS2 and improve the photo absorption of the composite. Thus, the composite shows excellent catalytic properties. Moreover, the kaolin mineral is very cheap and the using of the composite is very low-cost and practical.