Ruthenium-iridium nanosized coral

Ruthenium-iridium nanosized corals (RuIr-NC) are electrodes consisting of nanosized anisotropic ruthenium-iridium sheets for efficient electrolysis of water in acid discovered in the Kyoto University.^[1]^[2]

The RuIr-NC were discovered unintentionally at the Kyoto University, but then investigated and refined for the purpose of efficient electrolysis of water in acid and found to have very promising qualities in terms of performance and durability.^[1]

As of 2021 the researchers at Kyoto University report their RuIr-NC are composed of 94% ruthenium and 6% iridium with the exposed hexagonal atomic arrangement corresponding to a hexagonal closed-packed (HCP) crystalline lattice plane crystal structure. The nanosheets take the form of 3 nm thick sheets with a mean diameter of 57 ± 7 nm.^[1]^[2] The researchers found them suitable for use as both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) electrodes.^[1]

Their water splitting cell using RuIr-NC as both OER and HER electrodes is able to achieve 10 mA cm⁻²_geo at 1.485 V for 120 h without noticeable degradation. They report that, of the electrodes they evaluated for water electrolysis in acid, the RuIr-NC shows the highest intrinsic activity and stability.^[1]

The RuIr-NC is obtained by adding a mixture of RuCl3·nH2O and H2IrCl6 aqueous solutions to triethylene glycol solution containing polyvinylpyrrolidone at 230 °C.^[1]

The research team at Kyoto University published their work in February 2021 and presented it at the Chemical Society of Japan 101. General Meeting in March 2021.^[3]

References

^ ^a ^b ^c ^d ^e ^f Wu, Dongshuang; Kusada, Kohei; Yoshioka, Satoru; Yamamoto, Tomokazu; Toriyama, Takaaki; Matsumura, Syo; Chen, Yanna; Seo, Okkyun; Kim, Jaemyung; Song, Chulho; Hiroi, Satoshi; Sakata, Osami; Ina, Toshiaki; Kawaguchi, Shogo; Kubota, Yoshiki; Kobayashi, Hirokazu; Hiroshi, Kitagawa (2021-02-16), "Efficient overall water splitting in acid with anisotropic metal nanosheets", Nature Communications, 12 (1): 1145, Bibcode:2021NatCo..12.1145W, doi:10.1038/s41467-021-20956-4, hdl:2433/261722, PMC 7887272, PMID 33594054, S2CID 231945044
^ ^a ^b "Efficient production of hydrogen from water with new OER electrocatalyst – Success at Kyoto University - Highly stable atomic structure achieved with precision control". Science Japan. Japan Science and Technology Agency. 2021-04-26. Retrieved 2021-06-07. A research group led by Kohei Kusada, Program-Specific Associate Professor at the Hakubi Center for Advanced Research, Kyoto University and Professor Hiroshi Kitagawa and Program-Specific Assistant Professor Dongshuang Wu of the Graduate School of Science, Kyoto University, have succeeded in developing a water electrolysis catalyst that is 1,000 times more active and 10 times more stable than existing catalysts.
^ "Unprecedentedly efficient overall water splitting in acid with anisotropic metal nanosheets". Chemical Society of Japan. 2021-03-20. Retrieved 2021-06-09.