Mechanochemical redox-based synthesis of highly porous CoxMn1-xOy catalysts for total oxidation

Article abstract of DOI:10.1016/S1872-2067(20)63635-X

A mechanochemical redox reaction between KMnO₄ and CoCl₂ was developed to obtain a Co_xMn_1–xO_y catalyst with a specific surface area of 479 m² g^?1, which was higher than that obtained using a co-precipitation (CP) method (34 m² g^?1), sol-gel (SG) method (72 m² g^?1), or solution redox process (131 m² g^?1). During catalytic combustion, this Co_xMn_1–xO_y catalyst exhibited better activity (T100 for propylene = ~200 °C) than the control catalysts obtained using the SG (325 °C) or CP (450 °C) methods. The mechanical action, mainly in the form of kinetic energy and frictional heating, may generate a high degree of interstitial porosity, while the redox reaction could contribute to good dispersion of cobalt and manganese species. Moreover, the as-prepared Co_xMn_1–xO_y catalyst worked well in the presence of water vapor (H₂O 4.2%, >60 h) or SO₂ (100 ppm) and at high temperature (400 °C, > 60 h). The structure MnO₂·(CoOOH)_2.93 was suggested for the current Co_xMn_1–xO_y catalyst. This catalyst could be extended to the total oxidation of other typical hydrocarbons (T₉₀ = 150 °C for ethanol, T₉₀ = 225 °C for acetone, T₉₀ = 250 °C for toluene, T₉₀ = 120 °C for CO, and T₉₀ = 540 °C for CH₄). Scale-up of the synthesis of Co_xMn_1–xO_y catalyst (1 kg) can be achieved via ball milling, which may provide a potential strategy for real world catalysis.

Full text of DOI:10.1016/S1872-2067(20)63635-X

Chinese Journal of Catalysis 41 (2020) 1846–1854
a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m
j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c h n j c
Article
Mechanochemical redox-based synthesis of highly porous
Co catalysts for total oxidation
Mn1-xO
x y
a
b
c
a,
Jiafeng Bao , Hao Chen , Shize Yang , Pengfei Zhang *
a
School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY11973, USA
b
c
A R T I C L E I N F O
A B S T R A C T
Article history:
A mechanochemical redox reaction between KMnO
4
and CoCl
2
was developed to obtain a Co
x
Mn1–x
O
y
2
–1
Received 21 March 2020
Accepted 23 April 2020
Published 5 December 2020
catalyst with a specific surface area of 479 m g , which was higher than that obtained using a
2
–1
2
–1
co-precipitation (CP) method (34 m g ), sol-gel (SG) method (72 m g ), or solution redox process
2
–1
(131 m g ). During catalytic combustion, this Co
x
Mn1–x
y
O catalyst exhibited better activity (T100 for
propylene = ~200 °C) than the control catalysts obtained using the SG (325 °C) or CP (450 °C)
methods. The mechanical action, mainly in the form of kinetic energy and frictional heating, may
generate a high degree of interstitial porosity, while the redox reaction could contribute to good
Keywords:
Mechanochemical synthesis
Solid-state synthesis
Porous metal oxide
dispersion of cobalt and manganese species. Moreover, the as-prepared Co
well in the presence of water vapor (H O 4.2%, >60 h) or SO (100 ppm) and at high temperature
400 °C, > 60 h). The structure MnO ·(CoOOH)2.93 was suggested for the current Co catalyst.
Mn1–xO
x y
catalyst worked
2
2
(
2
Mn1–xO
x y
Co Mn1–xO
x y
catalyst
This catalyst could be extended to the total oxidation of other typical hydrocarbons (T90 = 150 °C for
ethanol, T90 = 225 °C for acetone, T90 = 250 °C for toluene, T90 = 120 °C for CO, and T90 = 540 °C for
Hydrocarbon combustion
CH
may provide a potential strategy for real world catalysis.
2020, Dalian Institute of Chemical Physics, Chinese Academy of Sciences.
4
). Scale-up of the synthesis of Co
Mn1–xO
x y
catalyst (1 kg) can be achieved via ball milling, which
©
Published by Elsevier B.V. All rights reserved.
1.
Introduction
toward commercialization. In particular, cobalt-manganese
oxides (Co
x
Mn1–x
O ) with multi-redox cycles are promising
y
The catalytic combustion of hydrocarbons is of great im-
candidates in the catalytic oxidation of hydrocarbons [16–19].
Several synthetic methods have been developed for these cata-
lysts. Among the parameters that determine the catalytic per-
formance of combustion catalysts, the porosity and surface
active oxygen species appear to be most critical [11,20,21].
portance in the control of volatile organic compounds (VOCs)
and automobile exhaust gases [1–6]. At present, most commer-
cial catalysts are noble-metal-based materials with low com-
bustion temperatures and long catalyst lifetimes [1,7–11]. In
contrast, transition metal oxide catalysts are inexpensive and
based on earth-abundant elements, but their activities and sta-
bilities are somewhat low [4,12–15], obstructing their path
The traditional strategies for Co
x
Mn1–x
O synthesis are the
y
co-precipitation (CP) method, sol-gel (SG) method [22] and
redox method [23], all of which are solution-based processes
*
Corresponding author. Tel: +86-21-54742893; Fax: +86-21-54742898; E-mail: chemistryzpf@sjtu.edu.cn
This work was supported by the National Natural Science Foundation of China (21776174), the Open Foundation of the State Key Laboratory of
Ocean Engineering (Shanghai Jiao Tong University of China) (1809), Shanghai Jiao Tong University Scientific and Technological Innovation Funds
(2019QYB06), China Shipbuilding Industry Corporation (CSIC) and Zhejiang XinAn Chemical Industry Corporation.
DOI: 10.1016/S1872-2067(20)63635-X | http://www.sciencedirect.com/science/journal/18722067 | Chin. J. Catal., Vol. 41, No. 12, December 2020

Chinese Journal of Catalysis, 41 (2020) 1846-1854. doi:10.1016/S1872-2067(20)63635-X

Chinese Journal of Catalysis, 41 (2020) 1846-1854. doi:10.1016/S1872-2067(20)63635-X

Chinese Journal of Catalysis, 41 (2020) 1846-1854. doi:10.1016/S1872-2067(20)63635-X

Chinese Journal of Catalysis, 41 (2020) 1846-1854. doi:10.1016/S1872-2067(20)63635-X

Chinese Journal of Catalysis, 41 (2020) 1846-1854. doi:10.1016/S1872-2067(20)63635-X

Chinese Journal of Catalysis, 41 (2020) 1846-1854. doi:10.1016/S1872-2067(20)63635-X

Chinese Journal of Catalysis, 41 (2020) 1846-1854. doi:10.1016/S1872-2067(20)63635-X

Chinese Journal of Catalysis, 41 (2020) 1846-1854. doi:10.1016/S1872-2067(20)63635-X