Ultrathin Silicon Oxide Overlayers Enable Selective Oxygen Evolution from Acidic and Unbuffered pH-Neutral Seawater

Seawater electrolysis is an attractive approach for producing clean hydrogen fuel in scenarios where freshwater scarce and renewable electricity abundant. However, chloride ions (Cl-) seawater can accelerate electrode corrosion participate the undesirable chlorine evolution reaction (CER). This problem especially acute acidic conditions that naturally arise at anode as a result of desired oxygen (OER). Herein, we demonstrate ultrathin silicon oxide (SiOx) overlayers on model platinum anodes are highly effective suppressing CER presence 0.6 M Cl- both unbuffered pH-neutral electrolytes by blocking transport to catalytically active buried interface while allowing (OER) occur there. The permeability SiOx 3 orders magnitude less than conventional salt-selective membrane used reverse osmosis desalination. also exhibit robust stability over 12 h chronoamperometry tests moderate overpotentials. promising step toward achieving selective stable without need adjust pH electrolyte.