Enhanced hydrogen production enabled by pulsed potential coupled sulfite electrooxidation water electrolysis system

Water electrolysis (WE) from renewable energy sources is broadly acknowledged as a critical future route for hydrogen production. Reducing energy consumption and enhancing hydrogen production rates are both important directions for future WE technology. In this work, pulsed potential coupled anodic sulfite (SO₃²⁻) electrooxidation water electrolysis (PSWE) system was proposed, enabling the production of hydrogen at low cell voltages as well as enhanced rates. The onset potential for the electrooxidation of sulfite to sulfate (SO₄²⁻) is as low as 0.6 V vs. RHE. Under pulsed parameter of 0.75 V vs. RHE and frequency of 0.5 Hz, the hydrogen production rate increased by 321 % compared to constant potential of 0.75 V vs. RHE. Pulsed potential increased the local concentration of SO₃²⁻ anions at the anode, thereby enhancing the accumulation of total charges on the electrode surface. In the H-cell, operating voltage as low as 1.15 V could drive current density of 10 mA cm⁻², demonstrating excellent hydrogen production capability and lower electricity consumption. The proposed PSWE system offers a potential route for coupling WE with intermittent renewable energy sources, as well as with low-energy consumption.