Effect of Citric Acid on the Hydrodesulfurization Performance of Unsupported Nickel Phosphide

The Ni–P incorporated citric acid (CA) catalysts with different CA/Ni molar ratios (x) were successfully prepared. The introduction of CA can change the structure of the catalyst precursor by complexing, and therefore affect the catalyst pore structures. The incorporation of CA into bulk Ni–P catalyst leads to a dramatic increase in surface area and pore volume. As compared to the Ni–P sample, the surface area of CA(2.0)–Ni–P increases 8.3 times. CA can also promote the formation of smaller, highly dispersed Ni2P particles, favoring more nickel phosphide phase. The DBT conversion of the CA(2.0)–Ni–P catalyst reached 96%, which increased by 34% as compared to the Ni–P sample.