Role of CuCo2S4 in Z-scheme MoSe2/BiVO4 composite for efficient photocatalytic reduction of heavy metals

The unique CuCo2S4 modified Z-scheme MoSe2/BiVO4 hybrid composites were prepared through hydrothermal method for efficient removal of heavy metals under visible light. The prepared samples showed remarkable photocatalytic properties for efficient removal of heavy metals. SEM, XRD, EDX and BET were used to determine the flower and needle like morphology, structure and elemental composition, and surface area. Whereas UV-Vis absorption and PL emission spectroscopy were found to be useful to observe the optical properties of samples. The monoclinic phase was observed and the crystallite size of the prepared photocatalyst calculated to be in the range of 15-25 nm. The band gap energy was found to be decreased due to incorporation of composite materials. This decrease in band gap could facilitate to absorb more energy in the visible range. The PL results showed that the addition of CuCo2S4 has played a significant role to inhibit the recombination of electrons/holes pair's during the photocatalysis. It was found that composite sample C/MBV-1 exhibited the 40 times higher efficiency when compared to pure sample. This outstanding photocatalytic performance of composite sample could be attributed to unique morphology, enriched absorption of visible part, large surface area and inhibited the recombination of charge-carriers to synergistic effect of CuCo2S4 and MoSe2/BiVO4.