A facile strategy for fabricating AgI–MIL-53(Fe) composites: superior interfacial contact and enhanced visible light photocatalytic performance

Metal–organic framework (MOF)-based composites have attracted great attention due to their potential applications in sustainable energy and environmental remediation. However, the development of the MOF-based composite as a visible-light photocatalyst for water treatment is still a challenge. Herein, through a simple grinding process, g-AgI/MIL-53(Fe) composites have been successfully fabricated. The resulting g-AgI/MIL-53(Fe) not only explored more active sites but also improved the interfacial contact between AgI and MIL-53(Fe), which is available for the separation and transfer of photogenerated charge carriers. Thus, the g-AgI/MIL-53(Fe) composites exhibited enhanced visible-light photocatalytic performance for Rhodamine B (RhB) degradation compared with the bare MIL-53(Fe) and pristine AgI under the same experimental conditions. After 45 min, RhB was completely mineralized by the g-AgI/MIL-53(Fe)-0.5 composite under visible light irradiation. In addition, acid blue (AB) and Methyl orange (MO) were also degraded by the g-AgI/MIL-53(Fe)-0.5 composite after 45 min irradiation, by 39% and 65%, respectively. Based on the photoelectrochemical analyses, it can be proven that the introduction of AgI could effectively hinder the recombination of photogenerated electron–hole pairs. Subsequently, the possible photocatalytic mechanism of the g-AgI/MIL-53(Fe)-0.5 composite has also been investigated in detail. Furthermore, g-AgI/MIL-53(Fe) composites also showed excellent photocatalytic stability. Under visible light irradiation, the RhB degradation activity was retained at approximately 70% of its original activity after five recycles, which makes it a potential candidate for large-scale applications.