Controllable synthesis of VSB-5 microspheres and microrods: growth mechanism and selective hydrogenation catalysis.
Nanoporous VSB-5 nickel phosphate molecular sieves with relatively well controllable sizes and morphology of microspheres assembled from nanorods were synthesized at 140 degrees C over a short time in the presence of hexamethylenetetramine (HMT) by a facile hydrothermal method. The pH value, reaction time, and ratio of HMT to NaHPO2.H2O crucially influence the morphology and quality of the final products. By adjusting the pH value of the initial reaction solution, the morphology changes from disperse rods to microspheres assembled from rods and finally to a large quantity of fibers, and the diameters of the VSB-5 rods can be varied. The catalytic activity of VSB-5 in selective hydrogenation of several unsaturated organic compounds was tested. Nickel(II) in VSB-5 can selectively catalyze hydrogenation of C=C in trans-cinnamaldehyde and 3-methylcrotonaldehyde. In addition, since nitrobenzene (NB) and 2-chloronitrobenzene could be reduced to aniline (AN) and 2-chloroaniline with high selectivity, VSB-5 could have potential applications in synthesizing dyes, agrochemicals, and pharmaceuticals.
Liu
Shu-Juan
SJ
Hefei National Laboratory for Physical Sciences at Microscale, Structural Research Laboratory of CAS, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
Cheng
Hai-Yang
HY
Zhao
Feng-Yu
FY
Gong
Jun-Yan
JY
Yu
Shu-Hong
SH
D002384:Catalysis; D006863:Hydrogen-Ion Concentration; D006865:Hydrogenation; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D015394:Molecular Structure; D043942:Nanotubes / Q000737:chemistry / Q000648:ultrastructure; D053770:Nanowires / Q000737:chemistry / Q000648:ultrastructure; D009532:Nickel / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014961:X-Ray Diffraction
D009532:Nickel