Nature of active sites in Ni2P hydrotreating catalysts as probed by iron substitution

- FeNi phosphides are highly active for 4,6-dimethyldibenzothiophene hydrodesulfurization (HDS).
- The catalysts are unusually selective for direct desulfurization to biphenyl products.
- X-ray absorption fine-structure indicates preferential Fe substitution in pyramidal sites.
- The unusual reactivity may be due to Ni occupation of surface tetrahedral sites.
- Density functional theory indicates stable FeNi structures with alternating Ni and Fe layers.