Immobilization of crystalline Fe2O3 nanoparticles over SiO2 for creating an active and stable catalyst: A demand for high temperature sulfuric acid decomposition

• Published in: Applied catalysis. B, Environmental Vol. 283; p. 119610
• Main Authors: Nadar, Ashish, Banerjee, Atindra Mohan, Pai, M.R., Meena, Sher Singh, Patra, A.K., Sastry, P.U., Singh, R., Singh, M.K., Tripathi, A.K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-04-2021; Elsevier BV
• Subjects: Catalysts; Catalytic activity; Crystal structure; Crystallinity; Decomposition; Ferric oxide; High temperature; Hydrogen generation; Immobilization; Impregnation; Iron oxides; Morphology; Mossbauer spectroscopy; Nanoparticles; Polyol; Porosity; Redox properties; Silica supported iron oxide; Silicon dioxide; Stability analysis; Sulfuric acid; Sulfuric acid decomposition; α-Fe2O3; α-Fe2O3; Polyol; Hydrogen generation; Silica supported iron oxide; Sulfuric acid decomposition
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2020.119610

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•Fe2O3/SiO2 was investigated for H2SO4 decomposition step prepared by polyol (FSP), solvothermal (FSST) and wet-impregnation methods (FSWI).•α-Fe2O3 in FSP and ε-Fe2O3 in FSWI and FSST as the major phase.•Rod shaped in FSP, spherical nanoparticles in FSST, while FSWI shows elliptical nanoparticles.•Higher pore confinement of Fe2O3, better anti-sintering behavior by virtue of Fe-O-Si interactions, higher degree of reduction in FSP.•Trend of catalytic activity followed as FSP > FSWI∼ FSST.
To address the issues of catalytic activity and stability of the promising Fe2O3/SiO2 catalyst for sulfuric acid decomposition, Fe2O3 was immobilized on SiO2 support by polyol, solvothermal and wet-impregnation methods and examined. The different methods yielded catalysts with varying crystal structure, porosity, morphology and redox properties which were investigated by XRD, Mössbauer spectroscopy, N2-BET surface area, SAXS, ED-XRF, HR-TEM, TPR/O and XPS techniques. The effect of the properties on the activity and stability was evaluated in a fixed-bed reactor and a structure-activity correlation was established. Above 750 °C the catalytic activity followed the order polyol > wet impregnation ∼ solvothermal. Stability of the sample prepared by polyol method was ascertained by 100 h experimental run at 800 °C. The higher activity and stability of the Fe2O3/SiO2 catalyst (polyol) is ascribed to the development of crystalline α-Fe2O3 dispersed phase, higher pore confinement, better support-active phase interactions and higher degree of reduction.