Influences of calcination and reduction methods on the preparation of Ni2P/SiO2 and its hydrodenitrogenation performance

摘要

The SiO2 supported Ni2P catalysts were prepared by H-2 temperature-programmed reduction (TPR) or plasma reduction (PR) of two precursors, which were obtained by co-impregnation of SiO2 with (NH4)(2)HPO4 and Ni(NO3)(2)center dot 6H(2)O with and without calcination. Their catalytic performances were evaluated by the hydrodenitrogenation of quinoline. The catalysts prepared by the TPR method showed a higher denitrogenation activity at low temperature (<= 320 degrees C) but a lower denitrogenation activity at high temperature (>= 340 degrees C) relative to those prepared by the PR method. The results of CO chemisorption and XPS analysis suggest that this can be explained that more metallic Ni species were present in the surface of the catalysts prepared by the TPR method, which enhanced their hydrogenation activity at temperatures below 340 degrees C. Calcination of the precursor is not necessary for the preparation of Ni2P/SiO2. However, both the dispersion and the surface composition of the Ni2P phase were affected by the calcination and reduction approaches. (C) 2015 Elsevier B.V. All rights reserved.