Photocatalytic activity of MnCl and Cu 5,10,15,20-Tetrakis(4-aminophenyl) porphyrins conjugated to graphene quantum dots against Rhodamine B dye using visible light

Abstract

The photocatalytic degradation of organic dyes presents a vital solution to mitigating environmental pollution caused by industrial effluents. This study explores the photocatalytic activity of metallo-porphyrins, specifically manganese (III) chloride 5,10,15,20-Tetrakis(4-aminophenyl) porphyrin (MnCl_TAPP) and copper (II) 5,10,15,20-Tetrakis(4-aminophenyl) porphyrin (CuTAPP), conjugated with graphene quantum dots (GQDs) for the degradation of Rhodamine B (RhB) dye under visible light irradiation. The incorporation of GQDs with the metallo-porphyrins significantly enhanced their photocatalytic performance. Among the tested composites, MnCl_TAPP_GQDs exhibited the highest degradation efficiency and rate constant, outperforming CuTAPP_GQDs. The degradation efficiencies of RhB under various conditions photolysis, CuTAPP, MnCl_TAPP, CuTAPP_GQDs, and MnCl_TAPP_GQDs were recorded as 12.06 %, 41.09 %, 51.09 %, 66.06 %, and 81.15 %, respectively. These findings demonstrate that the MnCl_TAPP_GQDs composite holds great potential for visible-light-driven photocatalytic applications, offering a promising approach to environmental remediation. • MnCl_TAPP soret peak shifted to the shorter wavelength due to metal dπ. • Incorporation of GQDs with metalated porphyrins enhances their degradation efficacy. • Photocatalytic degradation of Rhodamine B occurs through the formation of hydrogen peroxide H 2 O 2 . • H 2 O 2 can dissociate to form strongly oxidative and non-selective OH radicals during degradation processes. • FEEM was used to map different EX-EM fluorescence changes observed during degradation.