Abstract
Near-neutral HCO(3)(-) aqueous solution plays an essential role in respiratory, mineralization and catalysis, yet the interconversion between hydrated CO(2), HCO(3)(-) and CO(3)(2-) and the associated proton transfer under such proton-deficient conditions remain uncovered. Here we reveal that cation enables HCO(3)(-) to self-dissociate into OH(-) and CO(2) through a pH-independent process, where CO(2) hydration and subsequent proton transfer in acid-base reactions lead to the overall exchange of oxygen isotopes between HCO(3)(-) and H(2)O tracked by oxygen isotope-labeled Raman spectroscopy. Isolating HCO(3)(-) from cations with crown ether impedes HCO(3)(-) dissociation and the following reactions. Further molecular dynamics simulations demonstrate that the interplay between HCO(3)(-) and hydrated cations drives HCO(3)(-) dissociation. This study suggests a natural proton channel upon coupling HCO(3)(-) with cations.