Platinum, when used as the high-voltage needle electrode in pulsed corona electrical discharge in water, reduces the production rates of molecular hydrogen, hydrogen peroxide, and molecular oxygen by the discharge, in comparison to the production rates of those species when a nickel-chromium electrode is used. Reactions between hydrogen and oxygen and hydrogen and hydrogen peroxide are proposed to explain this result. It is proposed that these reactions occur on the surfaces of particles sputtered from the discharge electrode.