Three-Dimensionally Arranged NiSe₂ Nanosheets as an Efficient Electrocatalyst for Methanol Electrooxidation Reaction

Methanol oxidation stands out as a pivotal solution in addressing the global energy crisis and environmental pollution, owing to its practical applicability, high current density, and the ready availability of methanol as a fuel source. To effectively catalyze methanol oxidation, an electrocatalyst is imperious to overcome the activation energy barrier. Herein, a three-dimensionally arranged NiSe₂ nanosheet-based electrocatalyst is synthesized through a facile solvothermal followed by an annealing method. The catalyst's porous structure enhances catalytic efficiency by providing a substantial electrochemical surface area (ECSA) equivalent to 0.121 mF cm⁻². Notably, the electrocatalyst exhibits a remarkable response of 21.58 mA cm⁻² at an overpotential of 1.70 V vs RHE, accompanied by the lowest Tafel slope recorded at 39.14 mV dec⁻¹. The electronic circuit, represented by R_s(Q_f(R_fW(Q_dlR_ct)), aligns well with electrochemical impedance spectroscopy data, elucidating the reaction path and intrinsic properties. Furthermore, the catalytic performance is elucidated concerning ECSA and weight, revealing current densities of 5.60 mA cm⁻² and 71.34 mA mg⁻¹, respectively. Impressively, the catalyst demonstrates exceptional resistance to poisoning and sustained stability over a continuous 3600-s operation. This comprehensive study underscores the promising potential of the NiSe₂ nanosheet-based electrocatalyst for efficient methanol oxidation, providing valuable insights for advancing clean energy technologies.