Supporting Pd catalysts characterized significant different size distribution were obtained using PdCl2, [Pd(NH3)(4)](NO3)(2) and Pd(acac)(2) as precursors. High-resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), in-situ Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy were used to examine the dispersion of Pd. Catalytic performance measurements show that the activities for CO oxidation increase as the Pd particle size decreases and the O-2/CO ratio increases. The activities under oxygen rich conditions are significantly higher than those at near the stoichiometric conditions. Pd on TiO2 prepared by the Pd(acac)(2) precursor is highly dispersed, leading to a considerable activity for CO oxidation at near room temperature. CO oxidation on the 1 wt% Pd/TiO2 and under an O-2/CO ratio of 1 characterized an apparent activation energy of 36.7 kJ/mol, which is closed to those reported for CO oxidation on the supported Au catalysts. The present work demonstrates a high catalytic activity of highly dispersed noble metals, and suggests a promising approach of using noble metals as catalysts with exceeding high efficiency.National Natural Science Foundation of China [20873109]; National Basic Research Program of China (973 program) [2005CB221401, 2010CB732303]; Chinese Ministry of Education [309019]; Ph.D. Programs Foundation of Chinese Ministry of Education [200803841011]; Natural Science Foundation of Fujian Province, China [2008J0168

The electrochemical behavior of graphite anode in KF-KBF 4 molten salt at 500°C was studied by means of cyclic voltammetry, electrochemical impedance spectroscopy and chronopotentiometry techniques in this present work. The results showed that I-type "CF" compound is formed at 1.5 V vs. Pt-QRE, and II-type "CF" compound is formed at 2.1 V, while fluorine gas is formed at 4.9 V. The electrochemical reaction at 1.5 V is quasi-reversible, while the electrochemical reaction at 2.1 V is irreversible. The resistance of II-type "CF" compound is higher than I-type "CF" compound, and the value of charge transfer coefficient (β) for electrochemical formation II-type "CF" compound is calculated to be 0.26.