Study On Manipulation Of Composite Active Phases In Pd/ZrO₂ Catalysts For Alkane Combustion

In this work,we designed a novel In-site reduction technology for the preparation of nanocatalyst in which palladium supported on zirconia substrate in the system of non-polarization.Above the process,We regulate the reduction parameters to prepare a series of noble metal nanocatalyst with microdomain structure which was based on the interaction between support-metal(SMI).Firstly,acetylacetone solution was used to modify the surface of zirconia partially carbonated so that promoting the mutual dissolution between carrier precursor and metal-salt compound.Then,oxidized palladium were reduced to nanoparticles with the protection of capping agent and supported on zirconia simultaneously by regulating the reduction conditions.Finally,the metal nanoparticles near surface of support assembled a material with microdomain structure after calcination,which were driven by SMI.In addition,we prepared bimetallic nanocatalyst with doping the nickel precursor into palladium oxide so as to explore the influence of the introduction of transition metal on the structure and catalytic performance of the composite.Palladium species microdomain on zirconia detected with HAADF-STEM techniques.We manipulate the interaction between support and metal by changing the preparation parameters.It was found that the multi-precipitant improved surface structure and reducibility of ZrO2 and Pd-O-Zr species,thereby enhancing the catalytic performance.The catalysts prepared by in-situ reduction show higher alkane catalytic activities compared with catalysts prepared by conventional impregnation method.It was concluded that the catalyst prepared by the 2,5-di-tert-butyl-p-diphenol reducing agent(DTBHQ)changed the ratio of the active phase(Pd/PdOx).Similarly,the catalysts prepared by pre-reduction step improve the stability of Pd and PdOx on the zirconia support linking to catalytic activity.In general,multi-precipitant,DTBHQ and the ways of pre-reduction showed the different active phase of catalysts,so that promoting the interaction degree between the metal and the support via SMI.Therefore,it is an improvement route for the VOCs oxidation to optimize and control active phase in supported catalysts under SMI.