Iridium-cobalt mixed oxide electrode for efficient chlorine evolution in dilute chloride solutions

Electrochemical chlorine evolution reaction to improve the desalination of sea sand

Sea sand, a vital sand and gravel resource, is rich in chloride, which causes corrosion of steel reinforcements. This study investigates the effect of the electrochemical chlorine evolution reaction (CER) on the desalination of sea sand. The results indicate that the chlorine removal efficiency (RE) of sea sand increased from 48.76 to 56.40 % under optimal conditions: a current density of 15 mA/cm2, an electrolysis time of 1 min, and a sodium sulphate-supported electrolyte concentration of 0.05 mol/L. After 30 days of resting, the dissolved chlorine content in sea sand was 0.154 %, which was 21.03 % lower than that of the control group. The electrically active chlorine-mediated desalination process demonstrated excellent dechlorination ability, facilitated the transformation of metal and organic chlorine into liquid and gaseous forms, and reduced the slow release of chloride from sea sand. Therefore, CER is expected to be an efficient method for sea sand desalination.

Mn-doped Sequentially Electrodeposited Co-based Oxygen Evolution Catalyst for Efficient Anion Exchange Membrane Water Electrolysis

Designing high-performance and durable oxygen evolution reaction (OER) catalysts is important for green hydrogen production through anion exchange membrane water electrolysis (AEMWE). Herein, a series of Mn-doped Co-based OER catalysts supported on FeOxHy (FCMx) are presented to enhance the OER activity. Mn doping effectively reduces the size of the Co oxide particles, thereby augmenting the active surface area. Moreover, Mn doping induces the creation of oxygen vacancies, leading to an efficient structural conversion during the OER, which is confirmed via in situ Raman spectroscopy. Under optimal conditions, the catalyst exhibits an overpotential of 234.4 mV at 10 mA cm-2 and a Tafel slope of 37.2 mV dec-1 under half-cell conditions. The AEMWE single-cell system demonstrates a current density of 1560 mA cm-2 at 1.8 V at 60 °C with a degradation rate of 0.4 mV h-1 for 500 h at 500 mA cm-2. Our development of a robust OER catalyst represents notable progress in the field of nonprecious-metal water electrolysis, marking a step toward cost-effective green hydrogen production.

Translating the Optimized Durability of Co-Based Anode Catalyst into Sustainable Anion Exchange Membrane Water Electrolysis

Development of robust electrocatalysts for the oxygen evolution reaction (OER) underpins the efficient production of green hydrogen via anion exchange membrane water electrolysis (AEMWE). This study elucidates the factors contributing to the degradation of cobalt-based (Co-based) OER catalysts synthesized via electrodeposition, thus establishing strategic approaches to enhance their longevity. Systematic variations in the electroplating process and subsequent heat treatment reveal a delicate balance between catalytic activity and durability, substantiated by comprehensive electrochemical assessments and material analyses. Building upon these findings, the Co-based anode is successfully optimized in the AEMWE single-cell configuration, showcasing an average degradation rate of 0.07 mV h-1 over a continuous operation for 1500 h at a current density of 1 A cm-2 .