Perspective of catalysts for (Tri) reforming of natural gas and flue gas rich in CO2

Natural gas is an attractive feedstock for the synthesis of fuels and chemicals, currently derived from petroleum. The increasing global demand for more environment friendly processes and materials is a motivation to look for natural gas chemical conversion technologies. Carbon dioxide is a gaseous compound, which is also considered to be one of the main contributor to greenhouse effects. Methane tri-reforming is an important way for CO2 utilization aiming at hydrogen and syngas production, without separation of carbon dioxide. One expects that the tri-reforming process decreases the greenhouse gas emission. The main challenges in bringing this reforming technology to practice rest in catalysts development and the understanding of the reaction mechanisms for kinetic modeling and process optimization. What can be done? The main goal of this article is to describe factors to consider in search of catalysts suitable for the reforming of flue gas rich in CO2 and related processes. First, we discussed the relevant metal oxides catalysts and the effect of the supports for methane tri-reforming as well as combined or separated reforming processes for syngas production. Secondly, we described an investigation of two different supported catalysts based on multi-wall carbon nanotubes (MWCNT) and perovskite-type oxides. Structural changes of the catalysts as observed by different characterizations techniques for both in situ and post-reaction analyses. We showed that the tri-reforming processes are promising, but it is important to find out suitable, stable catalysts. Carbon nanotubes are promising as supports because they are capable of dispersing the metal particles. However, better understanding of the surface reaction, carbon formation mechanisms and the structural modifications are essential to explain these phenomena in further improvement and search of better catalysts.