Study on active sites of Mn-doped iron selenide on pencil electrode for electrocatalytic water splitting

Water electrolysis can be used to generate hydrogen, petrochemical fuel with high efficiency for use in power generation and a high gravimetric energy density that can be utilized to battle the exhaustion and pollution produced by current fossil fuels. The use of transition metal chalcogenides (TMC) as a potential alternative to precious metals in the water splitting process has recently sparked much attention. Hence, developing the future of the hydrogen economy depends on how well and reliably non-noble metal-based electrocatalysts can be made for the oxygen evolution reaction. Here, in the present work, a two-step hydrothermal method was employed to construct 3-dimensional (3D) Mn-doped iron selenide with microsphere architecture. The electrode’s distinctive 3D microsphere-like morphology leads to more active sites and faster electron movement over the perfect electrode, making it easier to release O 2 bubbles generated during oxygen evolution reaction (OER) catalysis. As a result, 10% Mn-doped iron selenide outperforms the lower overpotential of (133 mV) at a benchmark current density (j) deposited on the graphite pencil electrode (GPE). Hence, Mn-based electrocatalyst is one of the most intriguing possible applications. Graphical abstract Highlights In the present study, 3-dimensional mesoporous Mn-doped iron selenide microspheres morphology was fabricated by employing a two-step hydrothermal route. These remarkable 3-dimensional microsphere structures of 10% Mn-doped iron selenide release the O 2 bubbles produced during OER catalysis. The 10% Mn-doped iron selenide exhibits an outstanding OER activity having an ultralow overpotential of 133 mV to achieve a current density of 10 mA/cm 2 . The 10% Mn-doped iron selenide exhibits the highest stability of 30 h in alkaline solutions.