PW12/CN@Bi2WO6 composite photocatalyst prepared based on organic-inorganic hybrid system for removing pollutants in water

摘要

In the drive toward green and sustainable chemistry in wastewater treatment, it is necessary to explore more efficient and stable photocatalysts to achieve the degradation of antibiotic and reduction of heavy metal ions. To this end, an organic-inorganic hybrid PW12/CN@Bi2WO6 composite photocatalyst was prepared: PW12/CN composite was prepared by heating H3PW12O40, melamine and phytic acid; PW12/CN@Bi2WO6 was synthesized via PW12/CN and Bi2WO6 by hydrothermal method. The photocatalytic activity of as-prepared photocatalyst was evaluated by degrading tetracycline hydrochloride (TC) and reducing hexavalent chromium (Cr(VI)) under the simulated xenon light source. The results show the PW22/CN@Bi2WO6 composite always maintains high catalytic performance for TC and Cr6+ and has well cycle stability. After irradiation for 90 and 100 min, the most effective 10%-PW12/CN@Bi2WO6 achieved a removal rate of 98.7% for Cr(VI) and 97.5% for TC. Photoluminescence spectroscopy and photoelectrochemical results demonstrate that the charge separation is enhanced for the PW12/CN@Bi2WO6, attributed to the introduction of the organic-inorganic systems to enhance the absorbance of light energy, promote charge transfer and inhibit e(-) and h(+) pair recombination. In addition, the free radical scavenging test and electron spin resonance analysis (ESR) test indicate that the main species of action are h(+) and O-center dot(2)- in the photocatalytic oxidation reaction. Further, the mechanism of photocatalysis was proposed by Mott-Schottky. The strategy improving catalytic performance through organic-inorganic hybrid systems provides a new route for the development of photocatalysts.