Next Article in Journal
Electrodeposited Nanostructured CoFe2O4 for Overall Water Splitting and Supercapacitor Applications
Next Article in Special Issue
Effect of Preparation Method of Co-Ce Catalysts on CH4 Combustion
Previous Article in Journal
Dehydrogenation of Propane to Propylene Using Promoter-Free Hierarchical Pt/Silicalite-1 Nanosheets
Previous Article in Special Issue
Electropositive Promotion by Alkalis or Alkaline Earths of Pt-Group Metals in Emissions Control Catalysis: A Status Report
Article Menu
Issue 2 (February) cover image

Export Article

Open AccessArticle
Catalysts 2019, 9(2), 175; https://doi.org/10.3390/catal9020175

Comprehensive Comparison between Nanocatalysts of Mn−Co/TiO2 and Mn−Fe/TiO2 for NO Catalytic Conversion: An Insight from Nanostructure, Performance, Kinetics, and Thermodynamics

1
Key Laboratory of Renewable Energy Building Application Technology of Shandong Province, Shandong Jianzhu University, Jinan 250101, China
2
Department of Thermal Engineering, Shandong Jianzhu University, Jinan 250101, China
3
Engineering Laboratory of Power Plant Thermal System Energy Saving of Shandong Province, Shandong University, Jinan 250061, China
*
Author to whom correspondence should be addressed.
Received: 15 January 2019 / Revised: 7 February 2019 / Accepted: 9 February 2019 / Published: 13 February 2019
(This article belongs to the Special Issue Emissions Control Catalysis)
Full-Text   |   PDF [6096 KB, uploaded 13 February 2019]   |  

Abstract

The nanocatalysts of Mn−Co/TiO2 and Mn−Fe/TiO2 were synthesized by hydrothermal method and comprehensively compared from nanostructures, catalytic performance, kinetics, and thermodynamics. The physicochemical properties of the nanocatalysts were analyzed by N2 adsorption, transmission electron microscope (TEM), X-ray diffraction (XRD), H2-temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). Based on the multiple characterizations performed on Mn−Co/TiO2 and Mn−Fe/TiO2 nanocatalysts, it can be confirmed that the catalytic properties were decidedly dependent on the phase compositions of the nanocatalysts. The Mn−Co/TiO2 sample presented superior structure characteristics than Mn−Fe/TiO2, with the increased surface area, the promoted active components distribution, the diminished crystallinity, and the reduced nanoparticle size. Meanwhile, the Mn4+/Mnn+ ratios in the Mn−Co/TiO2 nanocatalyst were higher than Mn−Fe/TiO2, which further confirmed the better oxidation ability and the larger amount of Lewis acid sites and Bronsted acid sites on the sample surface. Compared to Mn−Fe/TiO2 nanocatalyst, Mn−Co/TiO2 nanocatalyst displayed the preferable catalytic property with higher catalytic activity and stronger selectivity in the temperature range of 75–250 °C. The results of mechanism and kinetic study showed that both Eley-Rideal mechanism and Langmuir-Hinshelwood mechanism reactions contributed to selective catalytic reduction of NO with NH3 (NH3-SCR) over Mn−Fe/TiO2 and Mn−Co/TiO2 nanocatalysts. In this test condition, the NO conversion rate of Mn−Co/TiO2 nanocatalyst was always higher than that of Mn−Fe/TiO2. Furthermore, comparing the reaction between doping transition metal oxides and NH3, the order of temperature−Gibbs free energy under the same reaction temperature is as follows: Co3O4 < CoO < Fe2O3 < Fe3O4, which was exactly consistent with nanostructure characterization and NH3-SCR performance. Meanwhile, the activity difference of MnOx exhibited in reducibility properties and Ellingham Diagrams manifested the promotion effects of cobalt and iron dopings. Generally, it might offer a theoretical method to select superior doping metal oxides for NO conversion by comprehensive comparing the catalytic performance with the insight from nanostructure, catalytic performance, reaction kinetics, and thermodynamics. View Full-Text
Keywords: NH3-SCR; nanostructure; kinetics; thermodynamics; manganese oxides NH3-SCR; nanostructure; kinetics; thermodynamics; manganese oxides
Figures

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Gao, Y.; Luan, T.; Zhang, S.; Jiang, W.; Feng, W.; Jiang, H. Comprehensive Comparison between Nanocatalysts of Mn−Co/TiO2 and Mn−Fe/TiO2 for NO Catalytic Conversion: An Insight from Nanostructure, Performance, Kinetics, and Thermodynamics. Catalysts 2019, 9, 175.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Catalysts EISSN 2073-4344 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top