Preparation And Preliminary Application Of NZP Family Phosphate Catalytic Material

In this study,NH4Zr2(PO4)3 which belong to NZP family had been synthesized by mechanochemical activation combined with hydrothermal crystallization method,whose phosphorus source was(NH4)2HPO4 and zirconium source was ZrOCl2·8H2O.The effects of milling time,hydrothermal time,and pH values on hydrothermal phase of the products were studied by single factor experiments.On the basis of above work,preliminary explorations of the synthesis of other crystal compounds belong to NZP family were also conducted.Furthermore,the crystal compounds belong to NZP family with mesoporous structure is formed by sol-gel route as well as MA method followed with hydrothermal treatment.The specific surface area,total pore volume,average pore size and pore size distribution were characterized.The effects of different templates used in sol-gel route and MA method were preliminary studied,with the view to obtain a new materials belong to NZP family which has large specific surface area and uniform pore size distribution.At last,the materials were put into use in oxidative dehydrogenation of propane to propylene,the effects of pore structure to conversion of propane were studied.The results show that:(1)Well-crystallized NH4Zr2(PO4)3 compounds can be synthesized by hydrothermally crystallizing at 160℃ for 24h,and the milling time was 6h,the ratio of HF to ZrO2 was 1 to 1.NaZr2(PO4)3 and KZr2(PO4)3 were also successfully synthesized by MA route while CaZr4(PO4)6 was not.(2)The better time when PEO put into system was during the MA process.The materials which keep mesoporous structure were obtained when the template were PEO,DDA,CTAB,and were not when SDBS were used.The specific surface area of mesoporous materials synthesized by MA method was smaller.(3)The specific surface area of CaZr4(PO4)6 could reach 51.2 m2/g when it was synthesized by sol-gel method and PEO was used as template.The specific surface area of CaZr4(PO4)6 could reach 67.2 m2/g when it was synthesized by sol-gel method and CTAB was used as template.When SDBS was used as template in sol-gel method,crystallized NZP materials was obtained,but its got a small specific surface,23.03m2/g,which means that SDBS is not a proper template for NZP family.(4)The catalyst was synthesized.when vanadium component load to the NZP family mesoporous materials.The catalyst was used in oxidative dehydrogenation of propane to propylene,and the conversion of propane could reach 21%when the temperature got to 550℃.