Ruthenium nanoparticles stabilized by mercaptan and acetylene derivatives with supercapacitor application

Ruthenium nanoparticles (RuHT, RuPET and RuPA) were prepared by hydrazine hydrate reduction of RuCl₃ and stabilized by the self-assembly of organic molecules (hexanethiol, phenylethanethiol and phenylacetylene). The sizes of these Ru nanoparticles were carried out by transmission electron microscopic measurement, with the average core sizes of 2.84 ± 0.55 nm, 3.06 ± 1.22 nm, and 3.10 ± 1.08 nm, respectively. The structures and properties of these Ru nanoparticles were further examined and verified by UV-vis, FTIR, ¹HNMR, XPS and fluorescent measurements. The performance of the supercapacitor was characterized by cyclic voltammetry and constant-current charge-discharge analysis. Ru nanoparticles exhibited enhanced supercapacitor behaviors as compared with blank electrodes. The Ru nanoparticles for supercapacitors in the H₂SO₄ electrolyte exhibited areal capacitances of 347.8, 304.9 and 229.1 mF cm^-2 for RuPET, RuPA and RuHT at a scan rate of 10 mV s^-1, and specific capacitances for 344.4, 249.3, 230.0 F g^-1 for RuPET, RuPA and RuHT at a current density of 0.5 A g^-1, respectively. The interfacial bonding between ruthenium and the outlayer organic ligands and varied ratio of ruthenium in high valence might be the reasonable explanation for the capacitance difference.