Investigation of polyethylene glycol (PEG) assisted solvothermal synthesis of CuCoO 2 nanosheets for efficient oxygen evolution reaction.

Water splitting to produce hydrogen is known as an effective way to alleviate the energy crisis, but the slow kinetics of the oxygen evolution reaction (OER) has been seriously restricting the development of water splitting technology. Therefore, low cost and high efficiency OER electrocatalysts have become substitutes for traditional noble metal-based catalysts. In this work, CuCoO 2 nanosheets (denoted by CCO2) were successfully synthesized under the regulation of surfactants and a solvent polyethylene glycol (PEG) by a solvothermal route using Cu-BTC and Co(NO 3 ) 2 ·6H 2 O as reactants. The experimental results confirmed that PEG addition could further reduce significantly the crystal size of the CCO2 nanosheets, i.e. , the size was about 150 nm and the thickness was 13 nm. The Ni@CCO2 electrode exhibits outstanding OER performance in 1.0 M KOH electrolyte, which shows the overpotential at 10 mA cm -2 is 378 mV, and the Tafel slope is 85 mV dec -1 . Moreover, the CCO2 nanosheets exhibit good structural and compositional stability after the 18 h constant current OER test. Therefore, this work may offer a novel insight into enhancing the OER performance of CuCoO 2 catalysts by decreasing their crystal size, and using a solvothermal route.