Catalysis Today, Vol.259, 340-346, 2016
The hydroxyapatite nanotube as a promoter to optimize the HDS reaction of NiMo/TiO2 catalyst
A composite containing TiO2 whiskers (TiO2(w)) and hydroxyapatite nanotube (nHA) with mosaic structure functioned as a support was successfully synthesized by a facile route. The TiO2(w) was prepared from potassium titanate and the novel single-crystalline hydroxyapatite nanotubes were synthesized via a distinctive biomimetic route. Properties of support and catalyst were characterized by SEM, TEM, XRD, FT-IR of adsorbed pyridine (in situ FT-IR), BET, TPR, and NH3-TPD. Catalytic activity of NiMo/TiO2(w)-nHA, and the effect of nHA contents on hydrodesulfurization (HDS) activity was performed. Results indicated the incorporation of nHA can weaken the Lewis acidity of TiO2 supports and decrease acidity of the NiMo/TiO2(w)-nHA catalyst. The addition of moderate nHA has weak influence on the textural and structural properties of the catalyst. NiMo/TiO2(w)-nHA exhibits higher HDS catalytic activity than that of NiMo/TiO2( w) catalyst under mild conditions of low temperature and pressure (280 degrees C and 2 MPa), and the catalytic performance of NiMo/TiO2(w)-nHA-0.1 is the best. The synergistic effects between TiO2(w) and nHA and acidity regulation contribute to improve the HDS catalytic activity of the nHA-doped samples. (C) 2015 Elsevier B.V. All rights reserved.