Fig. 3: The electrochemical performance of the single α-MnO₂ nanowire device.

a The schematic diagram of the single nanowire electrocatalytic device where a single α-MnO₂ nanowire is connected to the Au microelectrodes with Si₃N₄ as the insulating layer. b Polarisation curves and (c), Tafel plots of the single α-MnO₂ nanowire at different gate voltages. Inset: the schematic illustration of the working principle of gate voltage. V₁ represents the potential applied to the working electrode and V₂ is the gate voltage. d The statistics results of onset potential and Tafel slope plots at different gate voltages from different devices. The error bars represent the standard errors. e The gate voltage-tuned open circuit potential of the single α-MnO₂ nanowire. f Energy diagrams of MnO₂ electrochemical system with applied positive back gate voltage. The symbols in the diagram are vacuum level (E_vac), work functions of the back gate (Φ_G) and reference electrode (Φ_ref), electron affinity of MnO₂ (χ), electrical double layer (EDL), and vacuum level shifts in SiO₂ (Δϕ_G).