Figure reports the Nyquist plots collected from electrochemical impedance spectroscopy (EIS) measurements. The 2 nm NiFe alloy sample shows the lowest charge-transfer resistance of 3.4 Ω from the EIS fitting results (Fig. ), exhibiting an efficient charge-transport capability at the interface between photoanodes and the electrolyte solution. The photoanode with 2 nm NiFe alloy coating, leveraging enhanced thermodynamics and kinetics, shows the highest applied bias photonto-current efficiency (ABPE) value of 4.24% (Fig. ), which is nearly 5.7-fold higher than 1 nm NiFe coated sample.