Electrocatalytic activity of manganese tetra 4-aminophenyl porphyrin in the presence of graphene quantum dots

A manganese tetra 4-aminophenyl porphyrin (MnTAPP) was synthesized and attached to graphene quantum dots (GQDs) via covalent and x -x interaction to give MnTAPP@GQDs and MnTAPP-GQDs, respectively. There was an increase (using dynamic light scattering and transmission electron microscopy) in size of the GQDs in the presence of the porphyrin due to aggregation. The porphyrins in the absence and presence of GQDs were then adsorbed onto a glassy carbon electrode using drop and dry method. The electrochemical behavior was tested by cyclic voltammetry and chronoamperometry towards hydrazine. Both methods of com-bining MnTAPP with GQDs improved the activity of the electrocatalysis compared to individual components. MnTAPP@GQDs showed better catalytic rate constant of 4.36 x 10(2) Ms-1 and lowest LoD of 0.0023 mM fol-lowed by MnTAPP-GQDs. Furthermore, the sensor showed good selectivity in the presence of interfering ana -lytes. All probes showed good stability.

Automated summary

MnTAPP was synthesized and attached to GQDs to improve electrocatalysis activity, with MnTAPP@GQDs showing the best catalytic rate constant and lowest limit of detection. The sensors also demonstrated good stability and selectivity in the presence of interfering analytes.