Integrating Bi-containing metal-organic frameworks for enhancing their LED visible-light-driven photocatalytic activities towards Rhodamine dye

Tuning metal-organic framework (MOF) properties to enhance their catalytic activities has recently gained considerable attention. In this work, Bi(III) MOFs, including UU-200, CAU-17, and their integrated architecture, namely MIX-UCAU, were effectively prepared and characterized by various techniques, including FE-SEM, XRD, XPS, FT-IR, Raman, TGA, and EIS analyses. Results revealed that the UU-200 and CAU-17 frameworks were effectively integrated into a heterojunction MOF using a mixture of DMF and MeOH. The MIX-UCAU exhibited increased crystallinity, higher oxygen defect concentration and improved light absorption. The combined UU200-CAU-17 framework also showed enhanced photo-generated electron-hole pairs separation and immigration performance compared to single MOFs. The photodegradation experiments of Rhodamine B dye (RhB) in an aqueous solution showed that the MIX-UCAU had a high photodegradation efficiency of ca. 99 % within 90 min under energy-saving visible LED light irradiation, surpassing the bare UU-200 (-81 %) and CAU-17 (-89 %). In addition, the catalyst showed good photostability under successive cyclic experiments. The LC/MS and radical quenching tests revealed the degradation of RhB, including several steps, including the N-dealkylation, decarboxylation, deamination, and ring cleavages to tiny fragmentation products, and these procedures were predominantly controlled by the active species of O2 center dot- and h+. The study provides a facile and efficient strategy for developing photocatalysts for treating organic pollutants in wastewater.