Effect of Metal Precursors on the Performance of Pt/Y Catalysts for Isobutane-Butene Alkylation Reaction-Regeneration

Pt/Y catalysts were made by vacuum impregnation using Pt(NH3)4Cl2, Pt(NH3)4(NO3)2, Pt(NH3)4(CH3COO)2, and Pt(NH3)(NO2) as precursors. The effects of Pt precursors on the performance of Pt/Y catalysts on the physicochemical characteristics and catalytic performance were investigated. The results of X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), NH3-TPD, and Py-IR revealed that the type of platinum salt precursor had no significant effect on the fundamental physicochemical properties of the zeolite catalysts throughout the loading process, including the unit cell, relative crystallinity, specific surface area, pore volume, and acid properties. Also, the lifetime of alkylation of the supported catalysts remains the same compared with the one before Pt loading. However, the regeneration performance differs obviously; when the Pt loading was reduced to 0.3%, the catalyst (Pt–N–Y) prepared with Pt(NH3)4(NO3)2 as the precursor showed the best stable regeneration capability due to the highest Pt dispersion of Pt–N–Y according to transmission electron microscopy (TEM), thermogravimetric and mass-spectrometric (TG-MS) analyses, and H2-TPR analysis. In addition, the reason for this has been discussed in detail. The decomposition temperature of the Pt(NH3)4(NO3)2 precursor is only 240 °C, and the reduction temperature of the catalyst prepared by it is also lower, which avoids the agglomeration of Pt particles at high temperatures. At the same time, the one-step decomposition of Pt(NH3)4(NO3)2 reduced the degree of autoreduction of POx by NH3. Thus, with a lower Pt loading, Pt–N–Y exhibits steady reaction-regeneration performance in isobutane-butene alkylation.