Photoatalytic Degradation of Organic Pollutants in Water Under Visible Light by NH2‐MIL‐125(Ti‐Zr)@BiOClxI1‐x Composite Photocatalyst

Abstract

AbstractCombining two different semiconductors to construct heterojunction is an effective solution to the problem of high recombination rate of photo‐generated carriers. In this work, for further improvement of the photocatalytic performance of NH2‐MIL‐125(Ti−Zr)@BiOCl, NH2‐MIL‐125(Ti−Zr)@BiOClxI1‐x was synthesized by doping BiOI. The influence of BiOI doping amount on the photocatalytic performance of organic pollutant Acid Red B (ARB) was explored. The experimental results showed that the existence of BiOI enhanced the absorption of visible light and further reduced the recombination rate of photo‐generated carriers, thus improved the photocatalytic performance. The characterization of NH2‐MIL‐125(Ti−Zr)@BiOClxI1‐x was performed by XRD, SEM, TEM, EIS, DRS UV‐Vis DRS, and PL. Compared with the photocatalyst NH2‐MIL‐125(Ti−Zr)@BiOCl, the composite photocatalyst NH2‐MIL‐125(Ti−Zr)@BiOCl0.8I0.2 demonstrated superior visible‐light photocatalytic activity. With the illumination time of 90 min, the degradation rate of ARB was 94.6 %. After 3 times of recycling, the degradation rate of ARB was 91 %. The results of free radical quenching experiments showed that the degradation of ARB by NH2‐MIL‐125(Ti−Zr)@BiOCl0.8I0.2 was attributed to the oxidation of ⋅O2− and h+. A preliminary discussion on the photocatalytic mechanism was made.