Support Effect on the Performance of Ni2P Catalysts in the Hydrodeoxygenation of Methyl Palmitate

Irina Deliy,Evgeny Gerasimov,Pavel Aleksandrov,Ivan Shamanaev,Ilya Yakovlev,Olga Lapina,Evgeny Kodenev,Vera Pakharukova,Galina Bukhtiyarova

doi:10.3390/catal8110515

Abstract

The effect of support nature, SiO2 and γ-Al2O3, on physicochemical and catalytic properties of nickel phosphide catalysts in methyl palmitate hydrodeoxygenation (HDO) has been considered. Firstly, alumina-supported nickel phosphide catalysts prepared by temperature-programmed reduction method starting from different precursors (phosphate–Ni(NO3)2 and (NH4)2HPO4 or phosphite–Ni(OH)2 and H3PO3) were compared using elemental analysis, N2 physisorption, H2-TPR, XRD, TEM, NH3-TPD, 27Al and 31P MAS NMR techniques and catalytic experiments. The mixture of nickel phosphide phases was produced from phosphate precursor on alumina while using of phosphite precursor provides Ni2P formation with the higher activity in methyl palmitate HDO. Besides, the comparative study of the performances of Ni2P/SiO2 and Ni2P/Al2O3 catalysts demonstrates the apparent superiority of alumina-supported Ni2P in the methyl palmitate hydrodeoxygenation. Considering the tentative scheme of methyl palmitate transformation, we proposed that cooperation of Ni2P and acid sites on the surface of alumina provides the enhanced activity of alumina-supported Ni2P through the acceleration of acid-catalysed hydrolysis.

Highlights

Depletion of fossil oils resources, as well as the environmental issues of increased carbon emission, stimulates the development of new catalytic technologies for the production of transportation fuels from renewable [1,2,3]
In our previous study we have found out the synergetic effect of Ni2 P/SiO2 and γ-Al2 O3 physical mixture in hydrodeoxygenation of methyl palmitate, which was explained by the cooperation of the metal sites of Ni2 P/SiO2 and the acid sites of γ-Al2 O3 in consecutive metal-catalysed and acid-catalysed reactions of methyl palmitate conversion [31]
Two sets of Nix Py /γ-Al2 O3 catalysts were prepared by the incipient wetness impregnation from the phosphate- or phosphite-containing precursors (NiP_A/Al2 O3 or NiP_I/Al2 O3 samples, correspondingly) with the subsequent temperature-programmed reduction at 550, 600 and 650 ◦ C

Summary

Introduction

Depletion of fossil oils resources, as well as the environmental issues of increased carbon emission, stimulates the development of new catalytic technologies for the production of transportation fuels from renewable [1,2,3]. Triglyceride-based feedstocks, such as non-edible vegetable oils, animal fats and waste cooking oils, are the attractive resources that give a mixture of C14 -C18 alkanes in the hydrodeoxygenation (HDO) process [2,4,5]. This product called green diesel has a high cetane number and stability, low density and can be mixed with the fossil-derived fuels to improve their quality [6,7,8]. New systems containing base metals or their carbides, nitrides and phosphides have emerged as the catalysts for HDO of Catalysts 2018, 8, 515; doi:10.3390/catal8110515 www.mdpi.com/journal/catalysts

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