Fabrication of AgI/Ce-2MI Z-scheme heterojunction for enhanced photoreduction of Cr(VI) under visible light irradiation

Proper design and successful synthesis of photocatalysts with efficient interfacial charge transfer, strong redox capabilities, and strong environmental applications are critical. Herein, a novel Z-scheme heterojunction AgI/Ce2MI nanocomposite with redox-retaining properties was successfully prepared by a simple precipitation method. Compared with AgI and Ce-2MI, the efficiency of the optimized Z-scheme AgI/Ce-2MI composites in photocatalytic reduction of Cr(VI) in water within 75 min could exceed 90%. The reduction rate of AgI/Ce-2MI to Cr (VI) was 0.0277 min-1, which was 2.6 times and 6.8 times that of AgI and Ce-2MI, respectively. In addition, the cycle performance of AgI/Ce-2MI under different pH conditions was compared, and it was found that under the condition of pH= 2, its five-time catalytic activity stability showed good performance. Moreover, the enhancement process of reactive oxygen species & BULL;Oz and & BULL;OH were further verified by active radical capture experiment and ESR. Therefore, this study can provide a Z-scheme heterojunction nanocomposite photocatalytic process with environmental purification functions.

Automated summary

In this study, a novel Z-scheme heterojunction AgI/Ce2MI nanocomposite was successfully prepared, which showed efficient interfacial charge transfer, strong redox capabilities, and strong environmental applications. The optimized Z-scheme AgI/Ce-2MI composites exhibited a photocatalytic reduction efficiency of over 90% for Cr(VI) in water within 75 minutes, surpassing AgI and Ce-2MI. The reduction rate of AgI/Ce-2MI to Cr(VI) was 0.0277 min-1, which was significantly higher than AgI and Ce-2MI. Additionally, the catalytic stability of AgI/Ce-2MI showed good performance under pH=2 condition, and the enhancement of reactive oxygen species OZ and OH was further confirmed.