Investigating the correlation between deactivation and the carbon deposited on the surface of Ni/Al2O3 and Ni/La2O3-Al2O3 catalysts during the biogas reforming reaction
By N. Charisiou, L. Tzounis, V. Sebastián, S. Hinder, M. Baker, K. Polychronopoulou, M. Goula. Applications of Surface Science, 2019
166 citations recorded by the source corpus.
Abstract Ni/Al2O3 and Ni/La2O-Al2O3 catalysts were investigated for the biogas reforming reaction using CH4/CO2 mixtures with minimal dilution. Stability tests at various reaction temperatures were conducted and TGA/DTG, Raman, STEM-HAADF, HR-TEM, XPS techniques were used to characterize the spent samples. Graphitized carbon allotrope structures, carbon nanotubes (CNTs) and amorphous carbon were formed on all samples. Metallic Ni0 was recorded for all (XPS), whereas a strong peak corresponding to Ni2O3/NiAl2O4, was observed for the Ni/Al sample (650–750 °C). Stability tests confirm that the Ni/LaAl catalyst deactivates at a more gradual rate and is more active and selective in comparison to the Ni/Al for all temperatures. The Ni/LaAl exhibits good durability in terms of conversion and selectivity, whereas the Ni/Al gradually loses its activity in CH4 and CO2 conversion, with a concomitant decrease of the H2 and CO yield. It can be concluded that doping Al2O3 with La2O3 stabilizes the catalyst by (a) maintaining the Ni0 phase during the reaction, due to higher dispersion and stronger active phase-support interactions, (b) leading to a less graphitic and more defective type of deposited carbon and (c) facilitating the deposited carbon gasification due to the enhanced CO2 adsorption on its increased surface basic sites.
Subfields: Catalysis, Materials Chemistry, Mechanical Engineering
View Paper: https://www.semanticscholar.org/paper/4750fbadf98ad77591ebf66a216e013a4f5126c2
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Citations in the corpus
- Removal of Hydrogen Sulfide From Various Industrial Gases: A Review of The Most Promising Adsorbing Materials (2020, background): “However, pure metal oxides without a framework are characterized by low porosity, low surface area, and metal evaporation, and they are not able to resist sintering at higher temperatures, resulting in a reduced capacity for capturing H2S [90,91].”
- CO and CO2 methanation over Ni catalysts supported on CeO2, Al2O3 and Y2O3 oxides (2020, background): “isotherm of 15Ni/Al2O3 sample displayed classic IV type curve (IUPAC), corresponding to the typical feature of mesoporous materials [42,43].”