Formation and Catalytic Performance of Supported Ni Nanoparticles via Self-Reduction of Hybrid NiAl-LDH/C Composites

In the present work, hybrid NiAl-layered double hydroxide/carbon (LDHIC) composites with adjustable compositions were successfully assembled by crystallization of LDH in combination with carbonization of glucose under hydrothermal conditions, and further utilized as an integrated catalyst for the growth of carbon nanotubes (CNTs) in catalytic chemical vapor deposition (CCVD) of acetylene. The materials were characterized by X-ray diffraction. Fourier transform infrared, elemental analysis. thermogravimetric and differential thermal analysis, SEM, transmission electron microscopy, Xray photoelectron spectra, and Raman spectroscopy. The results revealed that the supported Ni nanoparticles with the small crystallite size of about 10 nm could be obtained by in situ self-reduction of as-assembled hybrid LDHIC composites in the course of CCVD. The carbon in the hybrid structure as a reducing agent played a key role for the high dispersion of resulting Ni nanoparticles. Furthermore, the Ni nanoparticles obtained here exhibited excellent activity for catalytic growth of CNTs, which could be delicately tuned by varying the compositions of hybrid composites. (C) 2010 American Institute of Chemical Engineers AIChE J, 56: 2934-2945, 2010