Electrochemical detection of hydrogen peroxide using micro and nanoporous CeO₂ catalysts

In this research work, focus has been made on a glassy carbon electrode (GCE) modified commercial micro and synthesized nano-CeO₂ for the detection of hydrogen peroxide (H₂O₂). Firstly, CeO₂ nanoleaves were prepared by solvothermal route. Both commercially available micro CeO₂ and synthesized nano-CeO₂ structures were analyzed by different characterization techniques. The Raman spectra of synthesized nano CeO₂ has more oxygen vacancies than micro CeO₂. SEM images revealed that the synthesized CeO₂ acquired leaf-like morphology. The catalyst nano CeO₂ offered mesoporosity from nitrogen adsorption-desorption isotherms with massive sites of activation for increasing efficiency. Experiments on determining H₂O₂ using micro CeO₂ or nano-CeO₂/GCE was conducted using cyclic voltammetry (CV) and amperometry. Enhanced H₂O₂ reduction peak current with lower potential was observed in nano-CeO₂/GCE. The influence of scan rate and H₂O₂ concentration on the performance of nano-CeO₂/GCE were also studied. The obtained results have indicated that nano-CeO₂/GCE showed improved electrochemical sensing behavior towards the reduction of H₂O₂ than micro-CeO₂/GCE and bare GCE. A linear relationship was obtained over 0.001 μM-0.125 μM concentration of H₂O₂, with good sensitivity 141.96 μA μM^-1 and low detection limit of 0.4 nM. Hence, the present nano-CeO₂ system will have a great potential with solvothermal synthesis approach in the development of electrochemical sensors.