Synthesis and boosting visible light photoactivity of Ag@AgI/CdWO4 towards refractory organic pollutants degradation based on interfacial charge transfer

Abstract

The high visible light active photocatalysts of Ag@AgI/CdWO4 (AICW) were synthesized via in situ deposition–precipitation and photoreduction methods. The physicochemical properties of crystal phases, morphologies, chemical compositions, optical properties and so on were characterized via several techniques. The results shown that the interface interaction between CdWO4 (CW) nanorods and Ag@AgI (AI) particles would enhance the visible light trapping, improve the surface area, promote the separation and transfer of photogenerated charge carrier and prolong the photoelectron lifetime. The AICW–3 with considerable reusability exhibited the optimum synergism of visible light photoactivity towards rhodamine B (RhB) and tetracycline (TC) degradation, in which the RhB and TC degradation ratio is 99.3% (24 min) and 77.0% (20 min), respectively, and the photocatalytic rate is 2.43 and 2.61 times that of AI, respectively. Furthermore, the free radical capture and electron spin resonance (ESR) experiments indicated that the O2−, h+ and OH species were the main radicals for RhB and TC degradation. Accordingly, the possible mechanisms of transfer and separation of photoinduced carriers as well as the generation of radicals for RhB and TC decomposition under visible light irradiation were proposed to lead the further improvement in environment remediation.