Conjugated Base Assists Proton Stripping off Pt for Alkaline H₂ Electrooxidation

Recent studies have revealed that slow transfer of the continuously formed H⁺ away from Pt surface can be a potential cause responsible for the extremely sluggish alkaline hydrogen oxidation (HOR). Herein, we show that anchoring mild oxyacid on carbon support is a generally effective approach to boost interfacial transfer of proton away from Pt. In alkaline solution, the surface anchored oxyacid is deprotonated generating affluent conjugated base surrounding Pt; taking C-PO₄ ^2- as a typical example, the conjugated base can readily seize the as-formed H⁺ around Pt (Pt-H⁺ + C─PO₄ ^2- → Pt + C─H₂PO₄) from HOR, which then are neutralized immediately by OH^- in the bulk solution (C─H₂PO₄ + OH^- → C─PO₄ ^2- + H₂O). Via such repetitive protonation and deprotonation, the as-formed H⁺ from HOR is efficiently transported away from Pt surface, thereby significantly improving the HOR rates. This strategy is found both effective for developing home-made Pt electrocatalysts as well as for modification of those commercial Pt/C. This study emphasizes the importance of enhancing interfacial proton transfer along the pursuit of efficient Pt electrocatalysts for alkaline HOR and provides a straightforward and generally effective strategy to address the issue.