Quinizarin Metal Complex based Electrocatalysts for Oxygen Evolution Reaction and DNA-Modified Electrodes for Drug Sensing

Abstract

In the realm of electrochemical advancements, this study delves into electrode modification as a pivotal strategy for enhancing water splitting efficiency and enabling trace-level detection of pharmaceutical compounds. A central challenge lies in Oxygen Evolution Reaction (OER), necessitating the development of high-performance, non-noble-metal electrocatalysts. This work harnesses the potential of metal–ligand coordination chemistry, exemplified through the synthesis of metal coordination complexes using the quinizarin ligand via a solvothermal approach. In alignment with sustainability, Earth-abundant transition metals were employed as metal sources, chosen for their wide availability and their d-orbitals' electron donation and acceptance capabilities. Among the synthesized electrocatalysts, the NiCoQ/FTO exhibited catalytic prowess as an integrated OER anode. Demonstrating excellent performance, it requires 269 mV overpotential to drive a current density of 10 mA/cm² in 0.05 M KOH solution. This impressive achievement is accompanied by a low Tafel slope of 33.1 mV dec⁻¹, further solidifying its standing as a formidable candidate. Importantly, this catalyst maintains its electrochemical durability for a remarkable duration of 40 consecutive hours, underscoring its practical viability. The study's second is dedicated to exploring the intricate interactions between three pharmaceutically significant drugs (paroxetine, azacytidine, and nelarabine) and biomolecules. Employing a multi-faceted approach encompassing electrochemical, fluorescence, and spectroscopic techniques, the research dissects the interaction mechanisms between the drugs and double-stranded calf thymus DNA, calculating essential binding parameters. Intriguingly, the investigation uncovers distinct interaction modes: Paroxetine-DNA and Nelarabine-DNA interactions adopt an intercalative approach, while Azacytidine-DNA interaction engages in groove binding. Elevating the practical implications, the electrode surface modification with ct-dsDNA leads to the creation of sensitive and selective biosensors. The oxidation of drugs emerges as a potent avenue for detecting drug-DNA interactions. Notably, Paroxetine-DNA interaction determination spans the concentration range of 1-50 μM, boasting a limit of detection (LOD) value of 0.31 μM, while Azacytidine-DNA interaction determination extends from 20 to 70 μM, exhibiting LOD values of 1.34 μM (adenine peak) and 9.8 μM (guanine peak). This voltammetric procedure is characterized by its efficiency, cost-effectiveness, and simplicity, rendering it a versatile analytical tool. VI This work embodies a comprehensive exploration of electrode modification's transformative potential in water splitting and pharmaceutical compound interaction studies. Through the synthesis of high-performance electrocatalysts and the creation of sensitive biosensors, this research not only contributes to fundamental understanding but also ushers in new possibilities for sustainable energy generation and pharmaceutical analysis