Nitrite production was calculated through spectrophotometric measurements, following established procedures. Briefly, the absorbance at 540 nm of a solution containing either known NO2 -concentrations or the post-electrolysis solution was combined with p-aminobenzenesulfonamide, N-(1-Naphthyl) ethylenediamine dihydrochloride, ultrapure water, and phosphoric acid was measured after 20 minutes of reaction time. H2 gas was quantified through gas chromatography measurements using an SRI GC. After 15 minutes of reaction, gas from the headspace of a sealed reactor was injected into the GC and quantified through the H2 peak area in the TCD detector channel, which was previously calibrated through measurements of known concentrations of H2 in N2.