Catalytic Performance Of Transition Metal Molybdenum Phosphide And Cobalt Phosphide

In recent years,transition metal phosphides not only have the properties of some noble metal catalysts,but also have better catalytic performance than transition metal carbides and nitrides.So,transition metal phosphides have potential research value and good research prospects in a sense.In this work,Molybdenum phosphide?MoP?was firstly used as a catalyst for partial oxidation of methane?POM?and its catalytic performance for POM was compared with that for dry reforming of methane?DRM?using stoichiometric feedstocks.It was found that the MoP phase was the dominant active site in POM and DRM reactions,and the activity would gradually decrease when more and more MoP was converted to Mo₂C phase?non-dominant active site?and then rapid deactivation would occur due to bulk oxidation of catalyst.The redox type mechanism over MoP catalyst was vitally important to keep its structure reasonably well during methane reforming reactions.The MoP catalyst revealed a higher catalytic stability in POM than in DRM,attributing to the higher H₂ yield obtained in POM,which can promote and maintain the redox cycle of catalyst.Besides,We developed a novel type of alumina-supported Co₂P catalyst for PROX reaction.In order to investigate the catalytic performance of Co₂P/?-Al₂O₃ catalyst on PROX,Firstly,Novel alumina-supported cobalt phosphide catalysts prepared from a series of precursors with different Co loading?3-40wt%?were synthesized by H₂-temperature-programmed reaction to prepare new Co₂P/?-Al₂O₃ catalysts,and designated as CoP-3,?CoP-10,?CoP-20 and CoP-40.Then,the catalytic performance of the Co₂P/?-Al₂O₃ catalyst for preferential CO oxidation?PROX?were investigated in excess H₂ at high temperature.It was found that the catalytic activities of these Co₂P/?-Al₂O₃catalysts were related to their Co loadings.The 10wt%Co₂P/?-Al₂O₃ catalyst showed the best PROX performance in 220 ^oC,which was attributed to its optimal microstructures?high surface area,small particle size and big amount of active site?.