Our electrochemical cell design for

Our electrochemical cell design for this study is a modified compression cell based on a model previously reported by our group and is shown in the Figure S1.41Cyclic voltammetry was used for the initial evaluation of the general electrochemical behavior of this system. Using a parallel-plate electrochemical cell equipped with a Ti working electrode, a glassy carbon counter electrode, and an Ag/AgCl reference electrode, (Ti/GC system) potential sweeps from 0 to −2 V versus RHE were performed at each of four pH values (∼0.77, 2.95, 10.05, and 13.00) in 0.1 M NO3−electrolytes.The resulting I−V curves (Figure S2) show that electrolytes of more extreme pH values give significantly higher total current densities than those of moderate pH, with the highest currents exhibited by the strongly alkaline electrolyte (pH 13.00) at more negative potentials, despite equal ion concentrations across solutions.