biostudies-literatureUnknown3(10)Wang SAlkali metal cations (AM⁺) and hydroxide anions (OH^-) intricately influence Pt-catalyzed hydrogen evolution and oxidation reactions (HER/HOR) in alkaline media, a topic of ongoing debate. Here, we systematically investigate their effects using twenty-eight electrolytes with independently varied Na⁺ and OH^- concentrations ranging from 0.001 to 1.0 M. Our studies reveal a strong correlation between electrical double layer (EDL) thickness and HER/HOR rates. Increasing the OH^- concentration positively shifts the potential of zero free charge and enhances the negative surface charge on Pt within the HER/HOR potential regime. This reduces the EDL thickness, strengthens interfacial electric fields, and facilitates water dissociation during HEPrecision chemistry604-611https://www.ebi.ac.uk/biostudies/studies/S-EPMC12569947biostudies-literatureElectrical Double Layer Effects on Alkaline Hydrogen Reactions on Platinum.PMC12569947Wan CHuang YWang SShah AHDuan XfalseElectrical Double Layer Effects on Alkaline Hydrogen Reactions on Platinum.Alkali metal cations (AM⁺) and hydroxide anions (OH^-) intricately influence Pt-catalyzed hydrogen evolution and oxidation reactions (HER/HOR) in alkaline media, a topic of ongoing debate. Here, we systematically investigate their effects using twenty-eight electrolytes with independently varied Na⁺ and OH^- concentrations ranging from 0.001 to 1.0 M. Our studies reveal a strong correlation between electrical double layer (EDL) thickness and HER/HOR rates. Increasing the OH^- concentration positively shifts the potential of zero free charge and enhances the negative surface charge on Pt within the HER/HOR potential regime. This reduces the EDL thickness, strengthens interfacial electric fields, and facilitates water dissociation during HE2025-01-01T00:00:00Z2025 Oct2026-06-05T09:34:17.941Z2026-05-15T03:12:57.529ZS-EPMC125699474117015810.1021/prechem.5c00019