Synthesis and Characterization of Mn₂O₃ and Its Electrochemical Properties in Relation to Dopamine

Introduction Manganese(III) oxide (Mn₂O₃) is a transition metal oxide that has gained significant attention due to its unique properties and potential applications in various fields, including catalysis, energy storage, and sensing. Dopamine, a neurotransmitter in the human brain, plays a crucial role in regulating several physiological processes as its detection is important in areas such as medical diagnostics and neurochemistry. The synthesis of Mn₂O₃ can be achieved through methods like precipitation, hydrothermal synthesis, or solid-state reactions. Aims The objective of this study is to synthesize Mn₂O₃, characterize its structure and morphology, and investigate its electrochemical properties toward dopamine. Materials and methods Materials used included manganese sulfate (MnSO₄), potassium permanganate, deionized water, a Teflon steel autoclave, and a hot air oven. For the synthesis of a hierarchical Mn₂O₃ rodlike shape, MnSO₄•H₂O (8 mmol) and potassium permanganate (8 mmol) were firstly dissolved in deionized water (40 mL) by stirring, which was then transferred to a Teflon-lined stainless steel autoclave (50 mL). This autoclave was sealed and maintained at 90℃ for six hours. Finally, the resultant Mn₂O₃ rods were collected by filtration, washed with distilled water and absolute ethanol for several times, and dried in air at 80℃. Mn₂O₃ rods were obtained by the calcinations of the as-prepared Mn₂O₃ rods at different temperatures. When Mn₂O₃ rods were treated at 600℃ for six hours in air, Mn₂O₃ rods could be collected. Results The X-ray diffraction (XRD) analysis shows that Mn₂O₃ is crystalline in structure and it matched with that of the Joint Committee on Powder Diffraction Standards (JCPDS). The field emission scanning electron microscopy (FE-SEM) shows the morphology of Mn₂O₃ is a particle with the size of 100 nm. Cyclic voltammetry response shows that compared to bare electrode, modified electrode shows the higher current response which indicates the sensing ability of the dopamine molecule. Conclusion  Mn₂O₃ was prepared using a hydrothermal technique, and the formation of nanoparticles (NPs) was verified through XRD, while the morphology was examined using FE-SEM. The Mn₂O₃ obtained was utilized in the detection of electrochemical dopamine, showing promise in the development of effective dopamine sensors. This study sets the stage for the integration of Mn₂O₃ into microfluidic systems for ongoing dopamine monitoring, presenting novel prospects for healthcare and neurochemical investigations. The exploration of various surface engineering approaches may additionally improve the electrochemical capabilities of Mn₂O₃ for the advancement of sensor technology.