The effect of preparation conditions on the properties of high-surface area Ni 2P catalysts

Abstract

The effect of preparation conditions on the properties of unsupported, high surface area Ni 2P catalysts, prepared by adding citric acid (CA) to precursor metal salt solutions prior to drying, calcination and temperature-programmed reduction (TPR), is reported. The highest Ni 2P surface area (∼220 m 2/g) was obtained from a precursor solution with a P/Ni mole ratio of 2 and a CA/Ni mole ratio of 2 that was dried, calcined at 500 °C and reduced in H 2 at 650 °C. Adding CA to the precursor salt solution is shown to yield amorphous precursors after calcination, rather than crystalline NiO and Ni 2P 4O 12 that was observed in the absence of CA, and the amorphous material yielded high surface area Ni 2P when reduced at temperatures above 600 °C. The high surface area Ni 2P favored the hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) by the hydrogenation route, although some direct-desulfurization was observed on catalysts reduced at lower temperature in which significant metaphosphate species were identified.