Electronic Tuning of Ni by Mo Species for Highly Efficient Hydroisomerization of <i>n</i>-Alkanes Comparable to Pt-Based Catalysts

Abstract

Modulation of the electronic structure of metal-based catalysts is a key to optimize the catalytic activity. Here, we have shown the electronic tuning of Ni by Mo species anchored on SAPO-11 (Ni–Mo/S-11) enabling the high-efficient hydroisomerization of n-alkanes comparable to commercial Pt/S-11, which is of great importance in producing fuel oils. The well-dispersed Ni particles intimately contacted with MoO2 are anchored on S-11 based on a vacuum-assisted route. There is the obvious presence of electron transfer from Mo species to Ni due to the intimate contact, which can increase the electron density around Ni and consequently promote H activation and desorption on Ni catalyst. Also, the good dispersion of Ni–Mo species on S-11 is favorable to expose more Brønsted acid sites of S-11, being responsible for the skeletal isomerization. These characteristics endow enhanced activity of 3.0Ni–0.5Mo/S-11 for the hydroisomerization of n-hexadecane with a high isomer yield of 81.4%, being comparable to 81.0% for 0.5 wt % Pt/S-11. The analysis of products showed similar isomerization and cracking mechanisms over 3.0Ni–0.5Mo/S-11 catalyst to Pt catalyst. Further, the presence of Mo species can enhance the stability, with no obvious change after 100 h continuous catalytic reaction. Both the catalytic activity and stability are much superior to those of monometallic Ni/S-11 and the reported non-noble-metal catalyst. This work focuses on developing high-effective non-noble-metal-based catalysts.