title: Manganese Oxide Nanoarray-Based Monolithic Catalysts: Tunable Morphology and High Efficiency for CO Oxidation.
abstract: A generic one-pot hydrothermal synthesis route has been successfully designed and utilized to in situ grow uniform manganese oxide nanorods and nanowires onto the cordierite honeycomb monolithic substrates, forming a series of nanoarray-based monolithic catalysts. During the synthesis process, three types of potassium salt oxidants have been used with different reduction potentials, i.e., K2Cr2O7, KClO3, and K2S2O8, denoted as HM-DCM, HM-PCR, and HM-PSF, respectively. The different reduction potentials of the manganese source (Mn(2+)) and oxidants induced the formation of manganese oxide nanoarrays with different morphology, surface area, and reactivity of carbon monoxide (CO) oxidation. K2Cr2O7 and KClO3 can induce sharp and long nanowires with slow growth rates due to their low reduction potentials. In comparison, the nanoarrays of HM-PSF presented shorter nanorods but displayed an efficient 90% CO oxidation conversion at 200 °C (T90) without noble-metal loading. Reducibility tests for the three monolithic catalysts by hydrogen temperature-programmed reduction revealed an activation energy order of HM-PSF > HM-DCM > HM-PCR for CO oxidation. The characterizations of oxygen temperature-programmed desorption and X-ray photoelectron spectroscopy indicated the abundant surface-adsorbed oxygen and lattice oxygen contributing to the superior reactivity of HM-PSF. The straightforward synthetic process showed a scalable, low-cost, and template-free method to fabricate manganese oxide nanoarray monolithic catalysts for exhaust treatment.
authors.affiliation: Department of Chemistry, University of Connecticut , 55 N. Eagleville Road, Storrs, Connecticut 06269-3060, United States.
authors.forename: Sheng-Yu
authors.initials: SY
authors.lastname: Chen
authors.affiliation: Department of Chemistry, University of Connecticut , 55 N. Eagleville Road, Storrs, Connecticut 06269-3060, United States.
authors.forename: Wenqiao
authors.initials: W
authors.lastname: Song
authors.affiliation: Department of Materials Science and Engineering & Institute of Materials Science, University of Connecticut , 97 N. Eagleville Road, Storrs, Connecticut 06269-3136, United States.
authors.forename: Hui-Jan
authors.initials: HJ
authors.lastname: Lin
authors.affiliation: Department of Materials Science and Engineering & Institute of Materials Science, University of Connecticut , 97 N. Eagleville Road, Storrs, Connecticut 06269-3136, United States.
authors.forename: Sibo
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Chemistry, University of Connecticut , 55 N. Eagleville Road, Storrs, Connecticut 06269-3060, United States.
authors.forename: Sourav
authors.initials: S
authors.lastname: Biswas
authors.affiliation: Department of Chemistry, University of Connecticut , 55 N. Eagleville Road, Storrs, Connecticut 06269-3060, United States.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Mollahosseini
authors.affiliation: Department of Chemistry, University of Connecticut , 55 N. Eagleville Road, Storrs, Connecticut 06269-3060, United States.
authors.forename: Chung-Hao
authors.initials: CH
authors.lastname: Kuo
authors.affiliation: Department of Materials Science and Engineering & Institute of Materials Science, University of Connecticut , 97 N. Eagleville Road, Storrs, Connecticut 06269-3136, United States.
authors.forename: Pu-Xian
authors.initials: PX
authors.lastname: Gao
authors.affiliation: Department of Chemistry, University of Connecticut , 55 N. Eagleville Road, Storrs, Connecticut 06269-3060, United States.|Department of Materials Science and Engineering & Institute of Materials Science, University of Connecticut , 97 N. Eagleville Road, Storrs, Connecticut 06269-3136, United States.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Suib
keywords: CO oxidation; array; manganese oxide; monolithic catalysts; nanorod