Preparation of Ni@Pd Core–Shell Nanoparticles Supported on KIT-6 by Ultrasound-Assisted Galvanic Replacement for Dodecahydro-<i>N</i>-ethylcarbazole Dehydrogenation
Zhaolu Feng, Ziting Liu, Xuefeng Bai
Abstract
Using Ni as a template and reductant, Ni core–Pd shell nanoparticles (Ni@Pd NPs) supported on KIT-6 (Ni@Pd/K6) were prepared by a galvanic replacement reaction under ultrasonic radiation. The characterization results show that the Ni@Pd core–shell NPs with an average diameter of 1.9 ± 0.3 nm are uniformly dispersed on KIT-6. The d-band center position of Pd in Ni@Pd core–shell NPs can be affected by both ligand and strain effects. The relationship between the d-band center of Pd and the selectivity of intermediates is a nearly straight curve. The dehydrogenation efficiency of dodecahydro- N -ethylcarbazole on Ni@Pd(6:1)/K6 is 100% only for 3 h at 180 °C and 95.5% for 6 h at 160 °C, which is better than the reported catalysts. The outstanding catalytic dehydrogenation performance of Ni@Pd(6:1)/K6 can be attributed to the synergistic effect of the ligand and strain effect, the high dispersion of core–shell NPs, and the weak H 2 binding ability of the catalyst.