A technology has been developed to produce clean hydrogen using waste alkaline water generated from semiconductor, metal etching, and cleaning processes that pose a high risk of environmental pollution. It is expected to revolutionize the clean hydrogen market through application to industrial water electrolysis facilities and hydrogen charging stations in the future.

Dr. Seung-Mok Choi's team at the Extreme Materials Research Institute of the Korea Institute of Materials Science (KIMS) has developed a non-precious metal oxygen-generating catalyst for direct waste alkaline water anion exchange membrane electrolysis that can produce clean hydrogen by directly utilizing waste alkaline water generated in large quantities in semiconductor and metal cleaning processes without pretreatment.

The research team applied the catalyst to a commercial-grade 64 cm² large-area unit cell and succeeded in stably producing hydrogen with a performance degradation rate of less than 5% for over 2,000 hours.

Waste alkaline water generated during semiconductor, metal etching, and cleaning processes is difficult to recycle due to high disposal costs and environmental pollution risks.

The anion exchange membrane electrolysis method can directly use waste alkaline water without separate purification, but impurity ions interfere with the electrolysis reaction, resulting in reduced efficiency and problems with catalyst durability.

The research team conducted a nickel-cerium oxidationWe focused on the fact that the water (Ni-CeOx) interface weakly binds to waste alkaline water impurities. We established a theoretical basis through DFT calculations (Professor Seo Min-ho's team at Pukyung National University) and developed a durable anion exchange membrane in collaboration with Professor Lee Jang-yong's team at Konkuk University.

The research team synthesized nickel and cerium oxides using a co-precipitation method, and achieved acceleration of the oxygen generation reaction and securing catalytic stability simultaneously by forming oxygen vacancies in the first step and maximizing electron-metal-support interactions in the second step.

In a 64cm² large-area unit cell test, the deterioration rate was less than 5% even after 2,000 hours of continuous operation, proving durability and efficiency comparable to commercial water electrolysis systems.

Existing freshwater-based electrolysis requires approximately 18 tons of purified water and $2,340 in purification costs to produce 1 ton of hydrogen. On the other hand, direct waste alkaline water electrolysis technology drastically reduces the cost of hydrogen production as it does not require purified water, and also reduces the burden of wastewater treatment.

Future application areas are expected to include industrial electrolysis facilities, hydrogen charging stations, direct seawater electrolysis, mobility fuel cells, and the power industry, and the company is currently pursuing expansion of demonstration scale in parallel with the development of mass production processes.

This study was conducted with the support of the National Research Foundation of Korea's H2 NEXT ROUND, Nano and Material Technology Development Project, and was published in 'Advanced Science' on June 9.

The research team said, “Non-freshwater-based electrolysis technology will revolutionize the clean hydrogen market,” and announced plans to develop a catalyst for direct seawater electrolysis in parallel.