Photocatalysis is one of the most promising technologies in wastewater treatment. However, the inactivity to visible light and the inconvenience to recycle severely limit its practical application. In this work, via a facile hydrothermal method, Fe3O4 NPs were integrated onto the surfaces of 3D ball-flower-like MoS2 microspheres as efficiently visible light responsive and magnetically recyclable photocatalysts. Experimental results indicate that, an optimal loading amount (20 wt %) of Fe3O4 NPs can not only effectively enhance the photocatalytic ability of the MoS2/Fe3O4 (MF) hybrid composite with approximately 2 times better than pure MoS2, but also make it conveniently recycle from water by an external magnetic field. The photoelectrochemical studies also reveal that the incorporation of Fe3O4 NPs can effectively enhance the charge transfer rate and accelerate separation of photoinduced charge carriers. The surface catalytic mechanism of MF hybrid composite was also explored through XPS spectra. With both the excellent photocatalytic performance and magnetical recyclability, the 20 wt %-MF hybrid composite is considered to be a promising and competitive photocatalyst for wastewater treatment utilizing solar energy.

Core–shell nanostructured materials with synergetic effects have gained increasing attention for their widespread applications in electrochemical water-splitting field. However, for most electrocatalysts, the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) can only work efficiently in neutral solution or alkaline solution, which hinders their further applications using untreated natural waters with a wide pH range, such as seawater (pH ∼ 7.5–8.5). In this paper, we report the synthesis of core–shell MoS2@CoO bifunctional electrocatalysts. The MoS2@CoO-coated carbon cloth electrode demonstrates excellent electrocatalytic properties for both OER and HER with 325 and 173 mV at a current density of 10 mA cm–2 and Tafel slopes of 129.9 and 83.0 mV dec–1 in 1 M KOH solutions, respectively. Additionally, the electrode can also work efficiently in neutral solutions (1 M PBS, pH = 7), showing good OER and HER activities for potential electrocatalytic water splitting applications in untreated natural waters.

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