Comparative Study of the Efficiency of Different Noble Metals Supported on Hydroxyapatite in the Catalytic Lean Methane Oxidation under Realistic Conditions
Zouhair Boukha,
Beatriz de Rivas,
Juan R. González-Velasco,
José I. Gutiérrez-Ortiz,
Rubén López-Fonseca
Affiliations
Zouhair Boukha
Chemical Technologies for Environmental Sustainability Group, Chemical Engineering Department, Faculty of Science and Technology, University of The Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain
Beatriz de Rivas
Chemical Technologies for Environmental Sustainability Group, Chemical Engineering Department, Faculty of Science and Technology, University of The Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain
Juan R. González-Velasco
Chemical Technologies for Environmental Sustainability Group, Chemical Engineering Department, Faculty of Science and Technology, University of The Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain
José I. Gutiérrez-Ortiz
Chemical Technologies for Environmental Sustainability Group, Chemical Engineering Department, Faculty of Science and Technology, University of The Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain
Rubén López-Fonseca
Chemical Technologies for Environmental Sustainability Group, Chemical Engineering Department, Faculty of Science and Technology, University of The Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain
The combustion of lean methane was studied over palladium, rhodium, platinum, and ruthenium catalysts supported on hydroxyapatite (HAP). The samples were prepared by wetness impregnation and thoroughly characterized by BET, XRD, UV-Vis-NIR spectroscopy, H2-TPR, OSC, CO chemisorption, and TEM techniques. It was found that the Pd/HAP and Rh/HAP catalysts exhibited a higher activity compared with Pt/HAP and Ru/HAP samples. Thus, the degree of oxidation of the supported metal under the reaction mixture notably influenced its catalytic performance. Although Pd and Rh catalysts could be easily re-oxidized, the re-oxidation of Pt and Ru samples appeared to be a slow process, resulting in small amounts of metal oxide active sites. Feeding water and CO2 was found to have a negative effect, which was more pronounced in the presence of water, on the activity of Pd and Rh catalysts. However, the inhibiting effect of CO2 and H2O decreased by increasing the reaction temperature.
