Role of oxygen vacancies in dendritic fibrous M/KCC-1 (M = Ru, Pd, Rh) catalysts for methane partial oxidation to H2-rich syngas production. (15th October 2020)

• Record Type: Journal Article
• Authors: Siang, T.J.; Jalil, A.A; Hamid, M.Y.S.; Abdulrasheed, A.A.; Abdullah, T.A.T.; Vo, D.-V.N.
• Is Part Of: Fuel. Volume 278(2020)
• Publication Date: 2020-10-15
• Subjects: Noble metal -- Oxy-reforming of methane -- Fibrous silica -- KCC-1 supported catalyst -- Synthetic gas; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2020.118360
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: A new catalyst catalyzes methane partial oxidation with high-rate syngas formation. Oxygen vacancies (OV) of catalysts possess strong metal-support interaction. Combustion-reforming pathway was affirmed for MPO over KCC-1 catalysts. In-situ ESR studies revealed the promotional effect of OV on MPO mechanism. Rh/KCC-1 achieved the H2 /CO ratio about 2 for Fischer-Tropsch synthesis. Abstract: The fibrous M/KCC-1 (M = Ru, Pd, Rh) catalysts prepared by microwave-assisted hydrothermal approach were investigated for methane partial oxidation (MPO) reaction at stoichiometric CH4 /O2 feed ratio and temperature of 500–800 °C. A drop in BET surface area with metal oxide addition suggesting the successful embedment of metal oxides on KCC-1. Low-angle XRD, FTIR and TEM analyses confirmed the formation of bicontinuous concentric lamellar morphologic structure, typical fingerprint of fibrous KCC-1. The H2 -TPR and ESR studies revealed that oxygen vacancy (OV) of KCC-1 not only beneficial for the metal-support interactions of catalysts but also strongly and dissociately bind with O2, CO2 and H2 O promoting the syngas formation rate. The post-reaction Raman spectroscopy measurement corroborated the M/KCC-1 catalysts hindered the graphitic carbon formation during reaction. The Rh/KCC-1 appeared to be the optimum catalyst as it exhibited the TOF of both CH4 consumption and H2 formation about 2-fold higher to other catalysts meanwhile achieving H2 /CO ratio about 2.16 that applicable for industrial applications. Based on the experimental MPO evaluation, post-reaction Raman spectroscopy and the in-situ ESR studies, the synergistic effects of metals and OV from fibrous KCC-1, where metal dissociates CH bonds in CH4 molecules whilst OV generates activated O 2− species from oxidants at the OV sites, are determined as the key factors for the enhancement in MPO activity.