Novelty without nobility: Outstanding Ni/Ti-SiO2 catalysts for propylene epoxidation

• Published in: Journal of catalysis 2020-06, Vol.386, p.94-105
• Main Authors: García-Aguilar, J., Fernández-Catalá, J., Juan-Juan, J., Such-Basáñez, I., Chinchilla, L.E., Calvino-Gámez, J.J., Cazorla-Amorós, D., Berenguer-Murcia, Á.
• Format: Article
• Language: English
• Subjects: Epoxidation; Nickel; Propylene; Silica; Single-site; Titanium
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2020.04.006

[Display omitted] •Ni-based catalysts have been prepared on titanosilicates by a simple route.•The prepared catalysts show outstanding propylene epoxidation performance.•DFT calculations and HRTEM have helped understand the catalysts behavior.•Formation of Ni-O-Ti interfaces is crucial to obtain efficient catalysts.•The catalysts are extremely cost-effective compared to Au-based systems. An efficient gas-phase production of propylene oxide (PO) with noble metal-free catalysts could modify the industrial output of this valuable compound. We present a novel catalyst based on well-dispersed Ni nanoparticles loaded on a Ti-SiO2 support for the propylene epoxidation reaction using H2/O2 mixtures. XPS, High Resolution Transmission Electron Microscopy (HRTEM), and UV–Vis corroborate both the small size of Ni particles and the excellent dispersion and incorporation of Ti as tetrahedral single site species into the silica framework. The catalytic results under steady-state conditions at low temperature (200 °C) show high PO selectivity (around 85%) with a substantial propylene conversion (over 6%) and excellent H2 efficiency (~37%) using only 0.5 wt% of Ni on Ti-SiO2 (Ti/Si = 0.01 M ratio). In this work, we have also carried out a preliminary DFT study to gain understanding of the characteristics that make this nickel catalyst active and selective for the propene epoxidation reaction.