High electrochemical performance of RuO₂–Fe₂O₃ nanoparticles embedded ordered mesoporous carbon as a supercapacitor electrode material

The electrode materials RuO₂ or RuO₂–Fe₂O₃ nanoparticle embedded OMC (ordered mesoporous carbon) are prepared by the method of impregnation and heating in situ. The mesoporous structure optimized the electron and proton conducting pathways, leading to the enhanced capacitive performances of the composite materials. The average nanoparticle size of RuO₂ and RuO₂–Fe₂O₃ is 2.54 and 1.96 nm, respectively. The fine RuO₂–Fe₂O₃ nanoparticles are dispersed evenly in the pore channel wall of the two-dimensional mesoporous carbon without blocking the mesoporous channel, and they have a higher specific surface area, a larger pore volume, a proper pore size and a small charge transfer impedance value. The special electrochemical capacitance of RuO₂–Fe₂O₃/OMC tested in acid electrolyte (H₂SO₄) is measured to be as high as 1668 F g⁻¹, which is higher than that of RuO₂/OMC. Meanwhile, the supercapacitor properties of the RuO₂–Fe₂O₃/OMC composites show a good cycling performance of 93% capacitance retention (3000 cycles), a better reversibility, a higher energy density (134 Wh kg⁻¹) and power density (4000 W kg⁻¹). The composite electrode of RuO₂–Fe₂O₃/OMC, which combines a double layer capacitance with pseudo-capacitance, is proved to be suitable for ideal high performance electrode material of a hybrid supercapacitor application. - Highlights: • The nanocomposites of RuO₂–Fe₂O₃/OMC are prepared by impregnation and heating in situ. • The fine RuO₂–Fe₂O₃ nanoparticles distribute in the pore channel wall of OMC. • We discuss a reversible redox reaction mechanism of RuO₂–Fe₂O₃/OMC in acid solutions. • RuO₂–Fe₂O₃ nanoparticles embedded OMC shows a higher supercapacitive performance.