Synthesis and Characterization of Discrete Nickel Phosphide Nanoparticles: Effect of Surface Ligation Chemistry on Catalytic Hydrodesulfurization of Thiophene

• Published in: Advanced functional materials Vol. 17; no. 18; pp. 3933 - 3939
• Main Authors: Senevirathne, K., Burns, A. W., Bussell, M. E., Brock, S. L.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 17-12-2007
• Subjects: Catalysts; Inorganic nanoparticles; Metals; Nickel; Structure-Property relationships
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.200700758

Discrete, unsupported nanoparticles of Ni
2
P have been prepared by using a solution‐phase method with bis(1,5‐cyclooctadiene)nickel(0) [Ni(COD)
2
] as the nickel source and trioctylphosphine (TOP) as the phosphorus source in the presence of the coordinating solvent trioctylphosphine oxide (TOPO). Ni
2
P nanoparticles prepared at 345 °C have an average crystallite size of 10.2 ± 0.7 nm and are capped with TOP and/or TOPO coordinating agents. The surface of the Ni
2
P nanoparticles can be modified by washing with CHCl
3
or by exchanging TOP/TOPO groups with mercaptoundecanoic acid (MUA). The surface areas of these nanoparticles are on the order of 30–70 m
2
g
–1
. As‐prepared and MUA‐capped nanoparticles undergo a phase transformation at 370 °C under reducing conditions, but CHCl
3
‐washed Ni
2
P nanoparticles retain the Ni
2
P structure. CHCl
3
‐washed and MUA‐capped nanoparticles exhibit higher HDS catalytic activity than as‐prepared nanoparticles or unsupported Ni
2
P prepared by temperature‐programmed reduction of a phosphate precursor. The surface modifications have a clear effect on the catalytic activity as well as the thermal stability of Ni
2
P nanoparticles under reducing conditions.