Fig. 3: Quantification of isotope-labeled O2 and H2O2 products in water oxidation.
a The O2 evolution in 2 M K2C16O3–H218O fresh solution at reaction current density 200 mA cm−2. The applied potential was turned off at 18 min and the later O2 evolution came from the H2O2 disproportionation, representing the ratio of H216O2:H216O18O:H218O2. b O2 evolution during water oxidation at different current densities in 2 M K2C16O3–H218O fresh solution. c O2 evolution during water oxidation at reaction current density 200 mA cm−2 after different reaction times in 2 M K2C16O3–H218O fresh solution. It should be noted that a 10 min reaction was conducted between each test. The top panel shows the I–t curves to indicate the duration of the time when the potential was applied to the cell. The mid panel was the molar flux of O2 evolution, and the bottom panel was the cumulative mole of the O2. The molar flux (mid panel) of gas evolution was denoted as ṅ, and the cumulative mole (bottom panel) of the gas was denoted as n. The flow rate of the carrier gas Ar was 2 mL min−1.
