| 초록 |
Nickel phosphide nanocrystals were synthesized by using a solution phase reaction of Ni(acac)2 and trioctylphosphine oxide (TOP) in the presence of coordinating solvent (trioctylphosphine oxide, TOPO). In this reaction, TOP works as a phosphorous precursor and coordinating solvent. TOPO is an extra coordinating solvent which prevents particles from aggregating during the formation of nanoparticles. XRD and EXAFS studies confirm that a Ni2P phase was successfully formed on Al2O3. TEM analysis showed that the particle size distribution of Ni2P/Al2O3–HT was in the range 20-30 nm, while the Ni2P/Al2O3–TOP gave rise to homogeneous nanoparticles of 5-9 nm in size. In agreement with the particle size distribution of Ni2P, the amount of CO uptake of the catalysts followed the sequence, Ni2P/Al2O3–TOP(148 μmol g−1)＞ Ni2P/Al2O3-HT(105 μmol g−1). As for the catalytic activity in HDS of 4,6-DMDBT, the Ni2P/Al2O3–TOP gave an HDS conversion of 75 %, which was much higher than that of Ni2P/Al2O3-HT catalyst which gave an HDS conversion of 50 %. These results thus demonstrate that the ligand stabilization is highly effective method to enhance the catalytic activity of the Ni2P/Al2O3 catalyst for deep HDS. |
