title: MnO(x) Nanoparticle-Dispersed CeO2 Nanocubes: A Remarkable Heteronanostructured System with Unusual Structural Characteristics and Superior Catalytic Performance.
abstract: Understanding the interface-induced effects of heteronanostructured catalysts remains a significant challenge due to their structural complexity, but it is crucial for developing novel applied catalytic materials. This work reports a systematic characterization and catalytic evaluation of MnOx nanoparticle-dispersed CeO2 nanocubes for two important industrial applications, namely, diesel soot oxidation and continuous-flow benzylamine oxidation. The X-ray diffraction and Raman studies reveal an unusual lattice expansion in CeO2 after the addition of MnOx. This interesting observation is due to conversion of smaller sized Ce(4+) (0.097 nm) to larger sized Ce(3+) (0.114 nm) in cerium oxide led by the strong interaction between MnOx and CeO2 at their interface. Another striking observation noticed from transmission electron microscopy, high angle annular dark-field scanning transmission electron microscopy, and electron energy loss spectroscopy studies is that the MnOx species are well-dispersed along the edges of the CeO2 nanocubes. This remarkable decoration leads to an enhanced reducible nature of the cerium oxide at the MnOx/CeO2 interface. It was found that MnOx/CeO2 heteronanostructures efficiently catalyze soot oxidation at lower temperatures (50% soot conversion, T50 ∼660 K) compared with that of bare CeO2 nanocubes (T50 ∼723 K). Importantly, the MnOx/CeO2 heteronanostructures exhibit a noticeable steady performance in the oxidation of benzylamine with a high selectivity of the dibenzylimine product (∼94-98%) compared with that of CeO2 nanocubes (∼69-91%). The existence of a strong synergistic effect at the interface sites between the CeO2 and MnOx components is a key factor for outstanding catalytic efficiency of the MnOx/CeO2 heteronanostructures.
authors.affiliation: †Centre for Advanced Materials and Industrial Chemistry (CAMIC), School of Applied Sciences, RMIT University, Melbourne VIC 3001, Australia.
authors.forename: Sudarsanam
authors.initials: S
authors.lastname: Putla
authors.affiliation: †Centre for Advanced Materials and Industrial Chemistry (CAMIC), School of Applied Sciences, RMIT University, Melbourne VIC 3001, Australia.
authors.forename: Mohamad Hassan
authors.initials: MH
authors.lastname: Amin
authors.affiliation: ‡Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India.
authors.forename: Benjaram M
authors.initials: BM
authors.lastname: Reddy
authors.affiliation: ⊥Chemistry Department, College of Science, King Saud University, Riyadh, Saudi Arabia.|§Chemistry Department, Faculty of Science, Sohag University, Sohag 82524, Egypt.
authors.forename: Ayman
authors.initials: A
authors.lastname: Nafady
authors.affiliation: ⊥Chemistry Department, College of Science, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Khalid A
authors.initials: KA
authors.lastname: Al Farhan
authors.affiliation: †Centre for Advanced Materials and Industrial Chemistry (CAMIC), School of Applied Sciences, RMIT University, Melbourne VIC 3001, Australia.
authors.forename: Suresh K
authors.initials: SK
authors.lastname: Bhargava
keywords: catalytic oxidation performance; cerium oxide; characterization; heteronanostructures; interface effects; manganese oxide