ABSTRACT
Ru-doped SnO2 nanoparticles were prepared by chemical precipitation and calcinations at 823 K. Due to high stability in diluted acidic solution, Ru-doped SnO2 nanoparticles were selected as the catalyst support and second catalyst for methanol electrooxidation. The micrograph, elemental composition, and structure of the Ru-doped SnO2 nanoparticles were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction, respectively. The electrocatalytic properties of the Ru-doped SnO2-supported Pt catalyst (Pt/Ru-doped SnO2) for methanol oxidation have been investigated by cyclic voltammetry. Under the same loading mass of Pt, the Pt/Ru-doped SnO2 catalyst shows better electrocatalytic performance than the Pt/SnO2 catalyst and the best atomic ratio of Ru to Sn in Ru-doped SnO2 is 1/75. Additionally, the Pt/Ru-doped SnO2 catalyst possesses good long-term cycle stability.
Subject(s)
Methanol/chemistry , Platinum/chemistry , Ruthenium/chemistry , Tin Compounds/chemistry , Catalysis , Electrochemistry , Microscopy, Electron, Scanning , Nanoparticles/chemistry , Oxidation-Reduction , Tin Compounds/chemical synthesisABSTRACT
We studied the antigens present in L929 mouse fibroblast or rabbit testicular cells, which had been infected or not with a prototype strain of Rickettsia tsutsugamushi, the causal agent of scrub typhus, and its attenuated variant. Immunoblotting revealed four antigens, designated 1, 1a, 2 and 3, which appeared to be specifically associated with infection with this organism. Antigens 1 and 1a had similar mol. wt of about 60 kD and antigen 2 and 3 had mol. wts of 45 kD and 28 kD respectively. Whereas antigen 1a, 2 and 3 were common to infection with either the virulent or the attenuated strains of the organism, antigen 1 was only detected in cells infected with the virulent strain and was reactive only with the antiserum raised against cells infected with that strain. In addition, two antigens were also detected by crossed immunoelectrophoresis, one of which was similarly associated with infection with the virulent strain as antigen 1, while the other was common to infection with either of the strains. It seems that the antigenic cross reaction between the two strains may account, in part at least, for the protection of mice against infection with the virulent strain afforded by the attenuated strain, while the loss or modification of antigen 1 might be associated with attenuation of the organism with respect to its virulence to mice.
