Electrolyser and Nanosensor for Efficient Oxygen Evolution Reaction and Sensitive Detection of Drugs

Abstract

This PhD thesis presents details of electrode modification and its application as a sensitive electrochemical platform for efficient water splitting and traces level detection of drugs. For water splitting the reaction for oxygen evolution has unfavourable thermodynamics since it needs energy to proceed. Lately scientists are focused to develop cheap oxygen evolving catalysts that are abundantly present in nature and have succeeded as well. But stability and efficiency of these catalysts still demands improvements. In this respect a part of the current work is focused on the development of an industrially favourable material that is durable and suitable for oxygen evolution reaction (OER) at low values of overpotential. Herein the synthesis of a novel and stable alkyl amine ligands containing NiFe complex material is reported, which displays remarkably high OER performance and extraordinary stability for OER stretching over days at varying temperature conditions under alkaline conditions. The powdered form of catalyst was found to give signal of OER at overpotential of 290 mV for consecutive 14 hours. The presence of binder in the preparation method of the powdered catalyst caused to affect its conductivity. Therefore, the catalyst was directly grown on nickel foam electrode which demonstrated improved water splitting performance as evidenced by 230 mV overpotential and stability upto consecutive 20 hours. After modification, the electrode was developed into a sensor for drugs analysis. Three different nanobiosensors were prepared using graphene oxide, multiwalled carbon nanotubes and gold and silver nanoparticles using screen printed electrode. Nanomaterials are associated with favorable characteristics including large surface area and rare electrical properties. So, nanomaterial-enriched deoxyribonucleic acid DNA sensors were developed for sensing the DNA binding events of a number of anticancer drugs. The results revealed decrease in signals response of DNA bases (adenine and guanine) due to the damage of the oxidizable moieties of these electroactive bases. The sensors demonstrated good values of sensitivity, selectivity, reproducibility, fast detection ability and to analyse drugs in its pharmaceutical dosage.