Preparation Of The Nzp Family Of Carrier And Its Load Of Precious Metal Catalysts

As a kind of new type material, the chemical property of phosphate material of NZP family is quietly steady. They aren't eroded by strong acid and strong alkali in most cases, and are oxidized hardly since they are in hot environment. The thermal expansion coefficient of NZP family material is extremely low, and the performance of thermal shock resistance is greatly good, so NZP family material could give loadful catalyst no bad heat-resisting impact performance, lengthen the service life of the catalyst as well.The subject prepares five material of [NZP] family ([CZP],[BZP], [CBZP] ,[KZP] and [SKZP]) via co precipitation method, and has systemedly studied the preparation methods and calcine temperature of [NZP] family on impact performance, looks structure and surface area.Ulteriorly, the thesis emphatically research that additive and modification work on performance of CZP.These carriers are used in the research of three way catalyst (TWO that purifies the tail gas of the automobile. Pd-only catalyst for automobile exhaust control were prepared in impregnation method with the supports of [CZP],[BZP], [CBZP] ,[KZP] and [SKZP],as while as their catalytic capability were tested; Auxiliary CeO₂, La₂O₃ are introduced in this test in order to investigate their impact on structure and performance of Pd/ CZP catalyst; we also prepared the P.d-only catalysts with the supports of [CZP] that modified by solution with the value was 3,5,7 and 9. The phase structure, reduction, specific surface area and catalytic capability of these samples are tested.These researches indicate that:(1) By the measure of calcination,coprecipition method can make NZP family material crystallize well; In the mean while, the effect of the calcine temperature of the carrier for looks structure and surface area is very obvious, it's fitting to choose 700-900℃;(2) The composition of the carrier for the dispersal of Pd in the catalysts isn't very perfect; The effect of the modification by the solution with difference value of pH for the reduction and the dispersal of Pd is not obvious.At the same time,auxiliary CeO₂ , La₂O₃ can not reduce the reduction temperature but also raise the dispersion of the Pd at the bodysurface;(3) The three way catalytic activity of Pd/CZP catalyst is similar with the one of Pd/y-Al₂O₃ catalyst.