Ni as the promoter on hydrogen spillover for better hydrogenative regeneration on Pt/Y based catalysts

Abstract

Hydrogenative regeneration of Pt/YA catalysts is vital to continuous operation of solid acid isobutane/butene alkylation. From the view of H2 activation, the mechanism of hydrogenative regeneration was investigated experimentally and theoretically. Herein with Pt/YA as reference, (Ni-Pt)/YA catalysts were prepared with almost identical cell parameter and different Ni/Pt contents by wet impregnation method following by several characterization methods, such as XPS, H2-TPR, H2-TPD, STEM-CS and Elemental mapping. Strong interactions between Ni and Pt were proven by XPS and H2-TPR. Moreover Ni can increase the capability of hydrogen spillover, which could be observed by H2-TPD, with the higher desorption temperature and more desorbed H2. DFT calculations revealed that hydrogen spillover is the rate determining step for the overall H2 activation over Pt/YA, and Ni as the hydrogen spillover promoter could couple with Pt to enhance the overall H2 activation because of almost 30% lower energy barrier for hydrogen spillover. With rather low Pt content, no obvious loss in lifetime in the 10 cycles of reaction-regeneration was observed over (5Ni-0.1Pt)/YA with rather stable product distribution.