Visible light assisted heterojunction composite of AgI and CDs doped ZIF-8 metal-organic framework for photocatalytic degradation of organic dye

Abstract

• CDs@ZIF-8@AgI was prepared by a solvent-free way coupled to ion deposition strategy. • Acridine Orange can be effectively degraded by CDs@ZIF-8@AgI under visible light. Water pollution induced by the productive process of organic dyes would lead to various diseases, and so treatment of the wastewater is an urgent task for protecting human health and ecological environment. In this work, visible light responsive heterojunction material based on silver iodide and carbon dots (CDs) doped ZIF-8 metal organic frameworks (CDs@ZIF-8@AgI) has been prepared by a green solvent-free strategy and in-situ ion deposition method. The CDs@ZIF-8@AgI composites have high photocatalytic performance for degradation of acridine orange (AO) dye under visible light, and the maximum degradation percentage can reach to 96.0%, which was estimated by the UV-visible spectroscopy. The porous structure and large surface area of the photocatalyst were favorable to absorption of the target dye on the catalyst, which can promote the kinetic degradation rate for low level concentration of the dye. The introduction of CDs into the AgI heterojunction can improve the electron transport efficiency and visible light absorption capacity, and thus significantly enhancing the photocatalytic activity of the catalyst. The photocatalytic mechanism was proposed as indirect Z-scheme heterojunction type based on the energy band structure of the catalyst. This work provides a visible light photocatalyst for removal of the AO dye in wastewater and offers a promising strategy for developing photocatalyst for treatment of organic pollutants in the environment using solar energy.