Preparation of Ruthenium-Porous Carbon Composite from a Chelate Resin and Its Application to Capacitor Electrode

The ruthenium-porous carbon composites were prepared from a commercial chelate resin (IRC748) with the adsorption of aqueous ruthenium ion (Ru3+) by carbonization (N2) and activation (CO2) at 800°C. The specific surface area and pore volume of the composites depended on the amount of Ru3+ adsorbed on the chelate resin. The ruthenium ion changed to metallic ruthenium when the ruthenium content of the composite (XRu) was below 10 mass%. When XRu was above 36 mass%, not only metallic ruthenium but also ruthenium oxide (RuO2) were found in the composite. The crystalline size of the ruthenium compounds from the Scherre equation were almost 30-33 nm by XRD analysis. The ruthenium-porous carbon composites were applied to electrode of capacitor. The specific capacitances (CS) of the composite were stable in the charge and discharge experiment. The CS depended on XRu; when XRu was small (0-30 mass%), Cs deceased linearly with increasing XRu. However, CS increased with increasing XRu (> 30 mass%). The effect of ruthenium content on the capacitance was also discussed by comparing the experimental results of physical mixing of porous carbon and ruthenium oxide.