Catalyst made of NiMo sulfide supported on hydroxyapatite: Influence of Al addition on support properties and on the catalytic conversion of thiophene

A hydroxyapatite and two apatites enriched with alumina have been synthesized to support NiMo sulfide. Hydroxyapatites are efficient supports of NiMo sulfide catalyst for desulfurization of thiophene. Addition of Al ions during the preparation results in an intimate mixture of crystalline apatite and amorphous AlPO 4 . This leads to an important increase in surface area and porous volume that is beneficial to the catalytic activity. The highest activity is obtained with calcium-deficient apatite because the presence of apatitic HPO 4 2- groups or related surface defects is required to improve the dispersion of the Mo ions in the oxidic precursor. The apatitic catalysts are superior to commercial NiMOP/Al 2 O 3 catalysts, which makes NiMo/apatite a good candidate for hydrotreating.