The study investigates the hydrogen evolution reaction (HER) on platinum (Pt) surfaces in alkaline media, focusing on the impact of pH on reaction kinetics. Using cyclic voltammetry (CV) and electrical transport spectroscopy (ETS), the researchers found that the Tafel slope and exchange current density of HER switch from ~110 mV/decade to ~53 mV/decade and from ~0.002 mA/cm² to >0.5 mA/cm², respectively, at pH 10. ETS measurements revealed a significant change in surface speciation at pH 10, suggesting a transition in interfacial water molecule orientation from O-down to H-down. Theoretical calculations using fixed-potential density functional theory (FP-DFT) confirmed that this orientation change weakens the O-H bond, enhancing HER kinetics. The study provides a molecular-level understanding of the pH-dependent HER kinetics in alkaline media, highlighting the importance of interfacial water structure in determining reaction rates.The study investigates the hydrogen evolution reaction (HER) on platinum (Pt) surfaces in alkaline media, focusing on the impact of pH on reaction kinetics. Using cyclic voltammetry (CV) and electrical transport spectroscopy (ETS), the researchers found that the Tafel slope and exchange current density of HER switch from ~110 mV/decade to ~53 mV/decade and from ~0.002 mA/cm² to >0.5 mA/cm², respectively, at pH 10. ETS measurements revealed a significant change in surface speciation at pH 10, suggesting a transition in interfacial water molecule orientation from O-down to H-down. Theoretical calculations using fixed-potential density functional theory (FP-DFT) confirmed that this orientation change weakens the O-H bond, enhancing HER kinetics. The study provides a molecular-level understanding of the pH-dependent HER kinetics in alkaline media, highlighting the importance of interfacial water structure in determining reaction rates.