Investigating the stability of Ni and Fe nanoparticle distribution and the MWCNT structure in the dry reforming of methane.

Camila Emilia KozonoeVinícius Modolo SantosMartin Schmal
Published in: Environmental science and pollution research international (2023)
Catalysts based on Ni and Fe nanoparticles deposited selectively on carbon nanotubes were investigated before and after the dry methane reforming. Three catalysts were synthesized and evaluated, varying the concentration of Ni inside and Fe outside the carbon tubes. BET analysis revealed that the acid treatment opened the ends of the nanotubes and resulted in a higher surface area. Transmission electron microscopy (TEM) showed 24 layers with inner diameter ranging from 4 to 6 nm and outer diameter ranging from 16 to 22 nm. Raman spectroscopy confirmed that after calcination at high temperature the structure of the nanotubes was maintained. X-ray diffraction (XRD) analysis of the catalysts confirmed the presence of NiO (2.6-3.2 nm) and Fe 2 O 3 (4.3 nm) crystallites. The catalytic tests presented high activity in dry methane reform (DRM). The catalysts 10Ni@CNT and 10Ni@CNT/5Fe presented conversions of CH 4 (63 and 67%) and CO 2 (72 and 88%), respectively, at 800 °C, under atmospheric pressure. Analysis after the reaction showed an increasing ratio of I D /I G , which indicates the formation of defects. The Raman analysis showed that even after calcination at high temperatures the structures of the nanotubes were mostly preserved, and TEM images showed that during the reaction, there were formation of nanotubes occurring randomly.