Supercritical CO2-Assisted Ru/CoO With Room-Temperature Ferromagnetism for Efficient Alkaline Oxygen Evolution.

Abstract

In this work, Ru/CoO catalysts with room-temperature ferromagnetism have been successfully fabricated by a supercritical CO2-assisted synthesis coupled with a subsequent annealing strategy. Furthermore, the efficient oxygen evolution reaction (OER) of the as-prepared catalyst has been demonstrated. Structural characterizations indicated that the room-temperature ferromagnetism of Ru/CoO is mediated by Ru─O─Co interfacial coupling. Experimentally, it shows the unannealed CoCO3-Ru showed modest OER activity with an overpotential of 284 mV at 10 mA cm-2 (η10) and a charge-transfer resistance (Rct) of 115 Ω, both higher than the benchmark values for commercial RuO2 (229 mV and 37.7 Ω), which indicates that the loading of Ru alone therefore did not trigger efficient catalysis. After annealing, the resulting Ru/CoO catalyst required only η10 of 150 mV and Rct of 34.1 Ω. In addition, durability tests confirmed stable operation at 100 mA cm-2 for 50 h. Therefore, all the results imply a correlation between spin ordering and OER catalytic performance.

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