Unraveling the mysterious failure of Cu/SAPO-34 selective catalytic reduction catalysts.
Aiyong Wang,Ying Chen,Eric D. Walter,Nancy M. Washton,Donghai Mei,Tamas Varga,Yilin Wang,János Szanyi,Yong Wang,Charles H. F. Peden,Feng Gao +10 more
TLDR
It is shown, via application of model catalysts with homogeneously dispersed isolated Cu ions, that Cu transformations resulting from low-temperature hydrothermal aging and ambient temperature storage can be semi-quantitatively probed with 2-dimensional pulsed electron paramagnetic resonance.Abstract:
Commercial Cu/SAPO-34 selective catalytic reduction (SCR) catalysts have experienced unexpected and quite perplexing failure. Understanding the causes at an atomic level is vital for the synthesis of more robust Cu/SAPO-34 catalysts. Here we show, via application of model catalysts with homogeneously dispersed isolated Cu ions, that Cu transformations resulting from low-temperature hydrothermal aging and ambient temperature storage can be semi-quantitatively probed with 2-dimensional pulsed electron paramagnetic resonance. Coupled with kinetics, additional material characterizations and DFT simulations, we propose the following catalyst deactivation steps: (1) detachment of Cu(II) ions from cationic positions in the form of Cu(OH)2; (2) irreversible hydrolysis of the SAPO-34 framework forming terminal Al species; and (3) interaction between Cu(OH)2 and terminal Al species forming SCR inactive, Cu-aluminate like species. Especially significant is that these reactions are greatly facilitated by condensed water molecules under wet ambient conditions, causing low temperature failure of the commercial Cu/SAPO-34 catalysts.read more
Citations
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The concept of active site in heterogeneous catalysis
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Poisoning-Resistant NOx Reduction in the Presence of Alkaline and Heavy Metals over H-SAPO-34-Supported Ce-Promoted Cu-Based Catalysts.
Penglu Wang,Lijun Yan,Yundong Gu,Sanchai Kuboon,Hongrui Li,Tingting Yan,Liyi Shi,Dengsong Zhang +7 more
TL;DR: A novel H-SAPO-34-supported ceria-promoted copper-based catalyst that demonstrated exceptional resistance against alkali, alkaline earth, and heavy metal poisoning during SCR of NOx is reported here.
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Opportunities and challenges in the development of advanced materials for emission control catalysts.
TL;DR: This Review assesses the state of the art for catalysing reactions related to emission control and also considers radical breakthroughs that could potentially completely transform this field.
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Solvation and Mobilization of Copper Active Sites in Zeolites by Ammonia: Consequences for the Catalytic Reduction of Nitrogen Oxides.
TL;DR: This work illustrates the power of precise control over a catalytic material, simultaneous kinetic and spectroscopic interrogation over a wide range of reaction conditions, and computational strategies tailored to capture those reaction conditions to reveal in microscopic detail the mechanistic features of a complex and widely practiced catalysis.
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Self-Protected CeO2-SnO2@SO42-/TiO2 Catalysts with Extraordinary Resistance to Alkali and Heavy Metals for NOx Reduction.
Sixiang Cai,Sixiang Cai,Tuoyu Xu,Tuoyu Xu,Penglu Wang,Lupeng Han,Sarawoot Impeng,Li Yue,Tingting Yan,Guorong Chen,Liyi Shi,Dengsong Zhang +11 more
TL;DR: This work proposes a novel self-protected anti-poisoning mechanism derived from the migration of sulfate in SO42-/TiO2 superacid to resist alkali and heavy metals and provides a new avenue for designing novel catalysts with outstanding resistance to alkaliand heavy metals.
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