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Synthesis and Characterization of Discrete Nickel Phosphide Nanoparticles: Effect of Surface Ligation Chemistry on Catalytic Hydrodesulfurization of Thiophene
Author(s) -
Senevirathne K.,
Burns A. W.,
Bussell M. E.,
Brock S. L.
Publication year - 2007
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200700758
Subject(s) - phosphide , nanoparticle , trioctylphosphine oxide , catalysis , thiophene , hydrodesulfurization , materials science , nickel , inorganic chemistry , nuclear chemistry , chemical engineering , organic chemistry , chemistry , nanotechnology , extraction (chemistry) , metallurgy , engineering
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.