Synthesis of g-C3N4/SmVO4 composite photocatalyst with improved visible light photocatalytic activities in RhB degradation

This paper reported novel graphitic carbon nitride (g-C3N4) and SmVO4 composite photocatalysts which were prepared through a simple mixing–calcination method. Multiple techniques, such as Brunauer–Emmett–Teller (BET) method, thermogravimetric/differential thermal analysis (TG–DTA), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy were applied to investigate the physical and photophysical properties of the catalysts. The XRD and FT-IR results indicate that the prepared sample is a two-phase composite of SmVO4 and g-C3N4. The TG–DTA result suggests that the real g-C3N4 concentration in the composite is lower than the theoretical value due to the catalysis of SmVO4. The DRS result shows that the addition of SmVO4 to g-C3N4 slightly changes the optical properties. The photocatalytic activity of the novel composite was investigated using rhodamine B (RhB) as a target pollutant. Results show that the g-C3N4/SmVO4 photocatalysts exhibit a significantly enhanced photocatalytic activity in degrading RhB. The optimal SmVO4 concentration and calcination temperature were also determined. Based on the band position, the synergetic effect of SmVO4 and g-C3N4 is the source of the enhanced photocatalytic activity, as proven by PL spectroscopy and transient photocurrent response.

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► A series of g-C3N4/SmVO4 composite is prepared by milling and heating method.
► The optimal g-C3N4 content and heating temperature is determined.
► The g-C3N4/SmVO4 composite degraded RhB 2× faster than g-C3N4 under visible light.
► The high activity can be attributed to the synergy of SmVO4 and g-C3N4.