(560gc) Surface Lattice Oxygen Activation Via Zr4+ Cations Substituting on a2+ Sites of MnCr2O4 Forming ZrxMn1-xCr2O4 Catalysts for Enhanced NH3-SCR Performance
AIChE Annual Meeting
2019
2019 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Poster Session: Catalysis and Reaction Engineering (CRE) Division
Wednesday, November 13, 2019 - 3:30pm to 5:00pm
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(x=0, 0.05, 0.1, 0.2) catalysts: (a) MnCr2O4; (b) Zr0.05Mn0.95Cr2O4;
(c) Zr0.1Mn0.9Cr2O4; (d) Zr0.2Mn0.8Cr2O4
and the schematic diagram showing the surface active species changes by Zr
doping and proposed reaction mechanism
Geh Geh 2 224 2019-04-12T06:02:00Z 2019-04-12T06:02:00Z 1 390 2227 18 5 2612 16.00
false 5.25 °õ 7.8 °õ 0 2 false false false EN-US ZH-CN X-NONE
line-height:150%">
font-family:" times new roman>The
emissions of NOx have caused great environmental issues, and the V2O5-WO3/TiO2
is the most widely used commercial catalyst for NH3-selective
catalytic reduction (NH3-SCR). However, there are many
disadvantages with this catalyst, such as the toxicity of vanadium, the high price of WO3, and the high optimal
operating temperature range of 350-420 o 12.0pt;line-height:150%;font-family:" times new roman yahei ui>C. Therefore, it is desirable to develop novel
catalysts with high efficiency, a broader and lower operating temperature
window, and environmental friendliness. Some spinel catalysts have been proven
to be effective in 150%;font-family:" times new roman>NH3-SCR, and the catalytic performance
usually can be further enhanced via doping a new element. In this paper, Z font-family:" times new roman>r4+ cations were incorporated
into the lattice of line-height:150%;font-family:" times new roman>MnCr2O4 spinel,
forming 12.0pt;mso-bidi-font-size:12.0pt;line-height:150%;font-family:" times new roman>a
series of novel ternary ZrxMn1-xCr2O4
mso-bidi-font-size:12.0pt;line-height:150%;font-family:" times new roman>(x 12.0pt;line-height:150%;font-family:" times new roman>=0, 0.05, 0.1,
0.2)catalysts for the first time. The as-prepared
Zr-doped catalysts all exhibited higher NOx conversion than undoped
MnCr2O4 catalyst. The Zr0.05Mn0.95Cr2O4
exhibited the best catalytic performance, with good stability in the presence
of H2O, the lowest 12.0pt;mso-bidi-font-size:12.0pt;line-height:150%;font-family:" times new roman color:black>T50 and 12.0pt;mso-bidi-font-size:12.0pt;line-height:150%;font-family:" times new roman color:black>T90 (149 o 12.0pt;line-height:150%;font-family:" times new roman yahei ui>C and 12.0pt;line-height:150%;font-family:" times new roman>201 o 12.0pt;line-height:150%;font-family:" times new roman yahei ui>C font-family:" times new roman>, respectively),
and the broadest font-family:" times new roman>T80 operation
window (183-354 line-height:150%;font-family:" times new roman>o font-family:" times new roman yahei ui color:>C line-height:150%;font-family:" times new roman>) under a gas hourly
space velocity of 112,000 h-1. The structural properties,
morphologies, surface species, acidity, and redox ability of ZrxMn1-xCr2O4
catalysts were characterized by a series of characterizations. The
results revealed that Zr4+ cations are successfully incorporated,
and the resultant lattice deformation changed the physical and chemical
properties of the catalysts remarkably.
The introduction of zirconium increased the
concentration and intensity of the acid sites, produced higher levels of
reducible species, and activated surface lattice oxygen following a
Mars-van Krevelen mechanism in NH3-SCR. Synergetic electron transfer effects might be
" times new roman>established
between Mn, Cr, and Zr cations, giving rise to higher levels of beneficial Mn3+,
Mn4+ and Cr5+ species (Mn2+
+ Cr3+ ↔ Cr2+ + Mn3+,
Mn3+ + Cr3+ ↔ Cr2+
+ Mn4+, Mn2+ + 2Zr4+ ↔ 2Zr3+ + Mn4+, Mn3+ + Zr4+
↔ Mn4+ + Zr3+,
font-family:" times new roman background:white>Cr3+ + 2Zr4+↔ Cr5+
+ 2Zr3+ line-height:150%;font-family:" times new roman>). The promoted electrons
transfer effects and surface lattice oxygen activation are further
substantiated by density functional theory (DFT) results.
emissions of NOx have caused great environmental issues, and the V2O5-WO3/TiO2
is the most widely used commercial catalyst for NH3-selective
catalytic reduction (NH3-SCR). However, there are many
disadvantages with this catalyst, such as the toxicity of vanadium, the high price of WO3, and the high optimal
operating temperature range of 350-420 o 12.0pt;line-height:150%;font-family:" times new roman yahei ui>C. Therefore, it is desirable to develop novel
catalysts with high efficiency, a broader and lower operating temperature
window, and environmental friendliness. Some spinel catalysts have been proven
to be effective in 150%;font-family:" times new roman>NH3-SCR, and the catalytic performance
usually can be further enhanced via doping a new element. In this paper, Z font-family:" times new roman>r4+ cations were incorporated
into the lattice of line-height:150%;font-family:" times new roman>MnCr2O4 spinel,
forming 12.0pt;mso-bidi-font-size:12.0pt;line-height:150%;font-family:" times new roman>a
series of novel ternary ZrxMn1-xCr2O4
mso-bidi-font-size:12.0pt;line-height:150%;font-family:" times new roman>(x 12.0pt;line-height:150%;font-family:" times new roman>=0, 0.05, 0.1,
0.2)catalysts for the first time. The as-prepared
Zr-doped catalysts all exhibited higher NOx conversion than undoped
MnCr2O4 catalyst. The Zr0.05Mn0.95Cr2O4
exhibited the best catalytic performance, with good stability in the presence
of H2O, the lowest 12.0pt;mso-bidi-font-size:12.0pt;line-height:150%;font-family:" times new roman color:black>T50 and 12.0pt;mso-bidi-font-size:12.0pt;line-height:150%;font-family:" times new roman color:black>T90 (149 o 12.0pt;line-height:150%;font-family:" times new roman yahei ui>C and 12.0pt;line-height:150%;font-family:" times new roman>201 o 12.0pt;line-height:150%;font-family:" times new roman yahei ui>C font-family:" times new roman>, respectively),
and the broadest font-family:" times new roman>T80 operation
window (183-354 line-height:150%;font-family:" times new roman>o font-family:" times new roman yahei ui color:>C line-height:150%;font-family:" times new roman>) under a gas hourly
space velocity of 112,000 h-1. The structural properties,
morphologies, surface species, acidity, and redox ability of ZrxMn1-xCr2O4
catalysts were characterized by a series of characterizations. The
results revealed that Zr4+ cations are successfully incorporated,
and the resultant lattice deformation changed the physical and chemical
properties of the catalysts remarkably.
The introduction of zirconium increased the
concentration and intensity of the acid sites, produced higher levels of
reducible species, and activated surface lattice oxygen following a
Mars-van Krevelen mechanism in NH3-SCR. Synergetic electron transfer effects might be
" times new roman>established
between Mn, Cr, and Zr cations, giving rise to higher levels of beneficial Mn3+,
Mn4+ and Cr5+ species (Mn2+
+ Cr3+ ↔ Cr2+ + Mn3+,
Mn3+ + Cr3+ ↔ Cr2+
+ Mn4+, Mn2+ + 2Zr4+ ↔ 2Zr3+ + Mn4+, Mn3+ + Zr4+
↔ Mn4+ + Zr3+,
font-family:" times new roman background:white>Cr3+ + 2Zr4+↔ Cr5+
+ 2Zr3+ line-height:150%;font-family:" times new roman>). The promoted electrons
transfer effects and surface lattice oxygen activation are further
substantiated by density functional theory (DFT) results.
mso-font-kerning:0pt">Key words:
12.0pt;line-height:200%;color:#2E2E2E;mso-font-kerning:0pt">
200%">ZrxMn1-xCr2O4; NH3-SCR;
surface lattice oxygen; electrons
transfer effects; DFT.
mso-font-kerning:0pt">
(x=0, 0.05, 0.1, 0.2) catalysts: (a) MnCr2O4; (b) Zr0.05Mn0.95Cr2O4;
(c) Zr0.1Mn0.9Cr2O4; (d) Zr0.2Mn0.8Cr2O4
and the schematic diagram showing the surface active species changes by Zr
doping and proposed reaction mechanism