(2lu) Iron-Based Catalyst for Production of Hydrogen and CNTs through the Catalytic Decomposition of Methane.

The promising technique of catalytic decomposition of methane (CDM) aims to produce hydrogen and valuable byproduct like CNTs without releasing greenhouse gas emissions . However, a significant challenge in making this process commercially viable is the development of an appropriate catalyst that can maintain long-term stability, exhibit strong catalytic activity and be cost-effective.

Nickel is the best catalyst for this process, but due to the rapid decomposition of nickel it is not suitable for the long run. Since iron-based catalysts performance is comparable with Ni catalysts because, Fe catalysts can survive temperatures of 700 °C and above, it is possible to achieve larger methane conversions with them than with Ni catalysts, leading to a favorable shift in the equilibrium. On the other side, greater temperatures hasten the catalyst's deactivation.

Using incipient technique, monometallic and bimetallic catalysts were made, containing 30 wt% metal of Fe, 30Fe:5Ni. The calculated quantity of spherical Alumina (100–150 mesh) was dissolved in the metal salt solution that had already been prepared. Before the water was removed by rotary vacuum evaporation, the produced slurry was constantly agitated for two hours. The slurry was then put in the oven to dry for an entire night at 120°C. The resulting cake was then calcined in the furnace for 5 hours at a ramp rate of 3 °C/min from ambient temperature to 750 °C. Before each reaction, the catalyst was reduced in-situ using hydrogen and nitrogen gas (1:1 by volume) at a total flow of 40 mL/min at NTP.

Experiments with monometallic 30% Fe of loading and bimetallic alloys of 30Fe-5Ni to examine the impact of adding Ni metal with various compositions on the methane conversion in fluidized bed reactor. The experimental findings of methane conversion were studied. The reaction was conducted at 800°C and an atmospheric pressure while the feed was kept at 4,000 mL h^-1 g ^-1 cat. space velocity. The outcomes demonstrate the impact of Ni addition as well as the effect of doping the principal support (Al₂O₃) metal-supported catalysts.The result is for the 30Fe-5Ni and is for the 30% Fe. The result illustrates that the addition of nickel (Ni) resulted in a slight increase in the conversion rate. However, the significant finding from the Raman spectroscopic is the quality of carbon nanotubes (CNTs) produced. It is evident that increasing the nickel content enhances the quality of CNTs. Because of the in-plane carbon-carbon stretching, the G band is a result of the perfect vibration of the graphite layers. The structural flaw in graphite is thought to be the cause of the D band (disorder mode). High resolution transmission electron microscopy (HRTEM), which shows the production of carbon nanotubes over a 30% Fe/Al₂O₃ catalyst. The monofilaments had a strange shape and looked-like chain-like multiwalled carbon nanotubes. They were made of linear plates that were attached end to end and had growing diameters that were encased in one another.