Synergy of vanadia and ceria in the reaction mechanism of low-temperature selective catalytic reduction of NOx by NH3

被引：30

作者：

Hu, Wenshuo ^{[1
]}

Zou, Renzhi ^{[1
]}

Dong, Yi ^{[1
]}

Zhang, Shuo ^{[1
]}

Song, Hao ^{[1
]}

Liu, Shaojun ^{[1
]}

Zheng, Chenghang ^{[1
]}

Nova, Isabella ^{[2
]}

Tronconi, Enrico ^{[2
]}

Gao, Xiang ^{[1
]}

机构：

[1] Zhejiang Univ, State Key Lab Clean Energy Utilizat, 38 Zheda Rd, Hangzhou 310027, Peoples R China

[2] Politecn Milan, Dipartimento Energia, Lab Catalysis & Catalyt Proc, Via La Masa 34, I-20156 Milan, Italy

来源：

JOURNAL OF CATALYSIS | 2020年 / 391卷

基金：

中国国家自然科学基金;

关键词：

Low-temperature SCR; Vanadia; Ceria; Redox mechanism; NO oxidative activation; FINDING SADDLE-POINTS; NITRIC-OXIDE; ALKALI RESISTANCE; ACTIVE-SITES; ACID SITES; SCR; AMMONIA; OXIDATION; IDENTIFICATION; ADSORPTION;

D O I：

10.1016/j.jcat.2020.08.002

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Elucidation of redox mechanism is vital to develop highly active catalysts for selective catalytic reduction (SCR) of NOx. Here, we apply an integrated experimental and theoretical approach to investigate low-temperature SCR (LT-SCR) mechanism over VOx/CeO2, a model system containing industrially-relevant vanadia active-species and an eye-catching redox support, i.e. ceria, frequently documented in SCR studies. We show that NO oxidative activation to a gaseous nitrite-precursor intermediate, which was trapped by BaO/Al2O3 and further spectroscopically and computationally validated, serves as a key step in LT-SCR. This scheme involves paired contributions from vanadia and ceria, in which vanadium stabilizes at +5 while Ce3+/Ce4+ varies in the redox cascade, and coupling of V5+-OH and proximal Ce-4(+)-O reduces the NO oxidative activation barrier. These findings progress the understanding of LT-SCR mechanism and deliver a specific perspective on the synergy of surface active-sites and supports, which are essential for the design of further improved SCR catalysts. (C) 2020 Elsevier Inc. All rights reserved.

引用

页码：145 / 154

页数：10

共 59 条

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