Chemical Vapor Deposition Synthesis of Carbon Nanomaterials over Lanthanum-Nickel Co-Loaded Catalyst Supported on Novel Radially Aligned Nano Rutile

Abstract

Deposition-precipitation using urea (DPU) method was efficiently used to load lanthanum and nickel catalyst nanoparticles onto the radially aligned nano rutile (RANR) support material to achieve a metal loading ranging from 1 to 10 wt. % La-Ni/RANR co-loaded supported catalysts. The PXRD peaks due to La occurred at 2θ values <30° and increased in intensities with an increase in La wt. % loading. The occurrence and distribution of the catalyst metal phases were analyzed using wavelength dispersive spectroscopy mapping (WDS) of the electrode probe microanalysis technique (EPMA). The reduction profiles showed TPR peaks that shifted to higher temperatures with an increase in metal wt. % loading. TEM micrographs of the La-Ni/RANR-supported catalysts showed that at different wt. % loadings, the particles deposited take different shapes and sizes with polydisperse La-Ni nanoparticles assuming a short rod-like structure at 1% wt loading. The La-Ni/RANR catalyst directly affected and influenced the nature of the carbon nanomaterials in CVD reactions under different parametric conditions of varied wt. % composition, temperature, flow rate, and time. It was concluded that the straight CNFs were catalyzed by the La end, while the coiled or twisted CNFs were catalyzed by the Ni end of this catalyst.