Study of the CO2 decomposition over doped Ni-ferrites

Abstract The H 2 reduced NiFe 2− x Cr x O 4 can be used to decompose CO 2 to C repeatedly. A series of nanocrystalline Ni-ferrite doping different contents of Cr 3+ were synthesized by mixed ions co-precipitation method and characterized by XRD, BET and TEM. The results showed that their crystallite sizes were 1–2 nm and BET surface area changed from 220 to 285 m 2 /g. The evaluation of the activity and stability indicated that Ni-ferrite with 4 wt% Cr 3+ dopant could be used repeatedly as many as 60 times and was transformed to Fe y Ni 1− y (0 y 5 C 2 gradually during the cycle decomposition of CO 2 to carbon, especially for no Cr 3+ sample. After the 60th reaction, although NiFe 2 O 4 phase just remained 2.1 wt%, the decomposition activity of Ni-ferrite with 4 wt% Cr 3+ was still 60% of initial activity. This fact suggests that nanocrystalline Fe y Ni 1− y (0 y 2 . The results from scanning electron microscopy (SEM), TEM and XRD show that the deposited carbon from CO 2 decomposition consisted of amorphous, crystallite and carbon nanotubes.