Ruthenium oxide/carbon composites with microporous or mesoporous carbon as support and prepared by two procedures. A comparative study as supercapacitor electrodes

Composites are prepared by deposition of nanoparticles of RuO 2· xH 2O (1–4 nm) on two carbons: microporous carbon (1.3 nm of average micropore size) and mesoporous carbon (11 nm of average mesopore size). Two-preparation procedures are used: (i) procedure A consisting of repetitive impregnations of the carbons with RuCl 3·0.5H 2O solutions, and (ii) procedure B based on impregnation of the carbons with Ru(acac) 3 vapour. The procedure B leads to supported RuO 2· xH 2O particles that appear more crystalline than those obtained by the procedure A. Specific capacitance and specific surface area of the composites are discussed as functions of the RuO 2 content, and different dependences for the composites derived from the two carbons are found. Mesoporous carbon is better support than microporous carbon. Procedure A leads to supported RuO 2· xH 2O particles with higher specific capacitance than the particles deposited by procedure B.