Boosting the efficiency of CoSe2 electrocatalyst for water splitting with Zn and Mn doping: Robust and durable electrocatalysts in alkaline media

Abstract

The growing concerns about the depletion of fossil fuel reserves and the resulting global environmental issues have driven efforts to identify alternative energy sources. Hydrogen, possessing high energy density and emitting no carbon, presents a promising alternative to fossil fuels as a clean energy carrier. Herein, we report a simple, low-cost, and rapid method for synthesizing Zn and Mn-doped CoSe₂ on nickel foam for overall water splitting at high current densities. Firstly, we synthesized CoSe₂ and investigated the effective parameters of CoSe₂ synthesis to find the optimum electrode. Then, Zn and Mn were doped into the CoSe₂ lattice and explored their electrocatalytic activity. Mn-CoSe₂ and Zn-CoSe₂ require only 415 and 561 mV, respectively, to reach −500 mA cm⁻², which is ideal. Also, Mn and Zn-doped CoSe₂ demonstrate good OER electrocatalytic performance with a potential of 1.95 and 1.98 V, respectively, at 300 mA cm⁻². The results of experiments indicate that the highly active electrocatalytic property of Mn-CoSe₂ and Zn-CoSe₂ results from the doping of Mn and Zn into the CoSe₂ lattice. Finally, Mn-doped CoSe₂ demonstrates excellent electrocatalytic activity, maintaining stability even after 12 h and 2000 cycles of testing for hydrogen and oxygen evolution reactions (HER and OER). Additionally, the Mn-CoSe₂ catalyst is synthesized via a facile, binder-free, and time-efficient method, making it economically viable. Furthermore, the structural and electronic properties imparted by the Mn-Co combination significantly improve charge transfer kinetics and catalytic stability under operating conditions. These advantages establish Mn-CoSe₂ as a promising candidate for sustainable and large-scale water-splitting applications, addressing the growing demand for clean and renewable hydrogen energy.