Controlled Synthesis Of Cuprprous Oxide And The Influence Of Facets Over The Performance For Preferential Oxidation Of Carbon Monoxide

As clean and effective strategic energy, hydrogen has become a powerful alternative to the traditional fuel to ease the energy crisis. The proton-exchange membrane fuel (PEMFC) has been regarded as a promising application as its promotion for development of hydrogen. There is still some CO after the reforming steam, which seriously poisons Pt anode of PEMFC. So, further CO purification must be carried out to decrease the CO concentration to acceptable level (<10 ppm). The preferential oxidation of CO (CO-PROX) has been proved to be the most simple and efficient method to removal of CO. Among the reported catalysts for CO-PROX, copper-ceria catalysts have gained tremendous attention due to it owns economic value and research significance.In this dissertation, different morphology Cu2O supports loaded by CeO2 were prepared as catalysts for CO-PROX. The as-prepared catalysts were characterized via SEM, TEM, XRD, N2 adsorption-desorption, H2-TPR, in situ FTIR, XPS techniques. Specific contents are as follows:1. The star Cu2O support was prepared via a liquid phase reduction method subsequent a series of CeO2/CuxO catalyst was prepared by impregnated method and been tested in CO-PROX reaction. The results show these catalyst have an excelent catalytic preformance. In this reaction, CO oxidation takes place at the interface of CeO2-CuxO catalyst, CO was chemical adsopted in the Cu+ species coming from the interface of copper-ceria. The carbonate and hydrogen carbonate species cover the surface of CeO2/CuxO catalysts at high temperature, and these species could cause the deactivation of the catalysts.2. A series of CeO2/CuxO catalysts were prepared by loading different amount CeO2 on the star Cu2O supports. The catalysts were characterized and studied in CO-PROX reaction, it shows the CeO2 has great influence on the constitute of interface. The large CeO2 particles were favorable for the formation of long periphery at the CeO2-CuxO interface, which could produce more active sites. The small CuO species formated with the increase of CeO2 is reduced to Cu" more easily, which is favorable for Cu2O over CO oxidation.3. The Cu2O supports exposed different index facets were prepared by a liquid phase reduction method and a series of CeO2/CuxO catalysts were synthesized by deposition-precipitation method. The Cu2O cubes, hexagons, multi-pods and polyhedron exposed (100), (110), (111) and (311) crystal planes. The polyhedral Cu2O enclosed by (311) high-index planes possessed greatest density of the "Cu" dangling bonds and apparent activation energy. The results indicate that the exposed facets of Cu2O supports affects catalytic performance in PROX, which coming from the difference in structure and texture properties.