Revealing the Formation and Reactivity of Cage-Confined Cu Pairs in Catalytic NOx Reduction over Cu-SSZ-13 Zeolites by In Situ UV–Vis Spectroscopy and Time-Dependent DFT Calculation DOI

Huarong Lei,

Dongdong Chen, Jia‐Yue Yang

et al.

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(33), P. 12465 - 12475

Published: Aug. 9, 2023

The low-temperature mechanism of chabazite-type small-pore Cu-SSZ-13 zeolite, a state-of-the-art catalyst for ammonia-assisted selective reduction (NH3-SCR) toxic NOx pollutants from heavy-duty vehicles, remains debate and needs to be clarified further improvement NH3-SCR performance. In this study, we established experimental protocols follow the dynamic redox cycling (i.e., CuII ↔ CuI) Cu sites in during catalysis by situ ultraviolet-visible spectroscopy infrared spectroscopy. Further integrating spectroscopic observations with time-dependent density functional theory calculations allows us identify two cage-confined transient states, namely, O2-bridged dimers μ-η2:η2-peroxodiamino dicopper) proximately paired, chemically nonbonded CuI(NH3)2 sites, confirm pair as precursor dimer. Comparative experiments reveal particularly high reactivity pairs NO-to-N2 at low temperatures. Our study demonstrates direct evidence formation paired CuI under zeolite confinement provides new insights into monomeric-to-dimeric transformation completing cycle over Cu-SSZ-13.

Language: Английский

Computational Methods in Heterogeneous Catalysis DOI
Benjamin W. J. Chen, Lang Xu, Manos Mavrikakis

et al.

Chemical Reviews, Journal Year: 2020, Volume and Issue: 121(2), P. 1007 - 1048

Published: Dec. 22, 2020

The unprecedented ability of computations to probe atomic-level details catalytic systems holds immense promise for the fundamentals-based bottom-up design novel heterogeneous catalysts, which are at heart chemical and energy sectors industry. Here, we critically analyze recent advances in computational catalysis. First, will survey progress electronic structure methods atomistic catalyst models employed, have enabled catalysis community build increasingly intricate, realistic, accurate active sites supported transition-metal catalysts. We then review developments microkinetic modeling, specifically mean-field kinetic Monte Carlo simulations, bridge gap between nanoscale insights macroscale experimental kinetics data with increasing fidelity. finally advancements theoretical accelerating discovery. Throughout review, provide ample examples applications, discuss remaining challenges, our outlook near future.

Language: Английский

Citations

336
Influence of framework Al density in chabazite zeolites on copper ion mobility and reactivity during NOx selective catalytic reduction with NH3 DOI
Siddarth H. Krishna, Anshuman Goswami, Yujia Wang

et al.

Nature Catalysis, Journal Year: 2023, Volume and Issue: 6(3), P. 276 - 285

Published: March 20, 2023

Language: Английский

Citations

65
Spatial Distribution of Brønsted Acid Sites Determines the Mobility of Reactive Cu Ions in the Cu-SSZ-13 Catalyst during the Selective Catalytic Reduction of NOx with NH3 DOI
Yu Fu,

Wenqing Ding,

Huarong Lei

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(16), P. 11141 - 11151

Published: April 10, 2024

The formation of dimer-Cu species, which serve as the active sites low-temperature selective catalytic reduction NO

Language: Английский

Citations

21
Competition between Mononuclear and Binuclear Copper Sites across Different Zeolite Topologies DOI Creative Commons
Asanka Wijerathne,

Allison M. Sawyer,

Rohil Daya

et al.

JACS Au, Journal Year: 2024, Volume and Issue: 4(1), P. 197 - 215

Published: Jan. 4, 2024

A key challenge for metal-exchanged zeolites is the determination of metal cation speciation and nuclearity under synthesis reaction conditions. Copper-exchanged zeolites, which are widely used in automotive emissions control potential catalysts partial methane oxidation, have particular evidenced a wide variety Cu structures that observed to change with exposure conditions, zeolite composition, topology. Here, we develop predictive models CHA, MOR, BEA, AFX, FER topologies using interatomic potentials, quantum chemical calculations, Monte Carlo simulations interrogate this vast configurational compositional space. Model predictions rationalize experimentally differences between Cu-zeolites wide-body literature, including populations, structural variations, methanol per yields. Our results show both topological features commonly Al-siting biases MOR increase population binuclear sites, explaining small mononuclear sites these materials relative other such as CHA BEA. Finally, machine learning classification model determine preference form or at different Al configurations 200 international database. reveal several extreme ends vs spectrum, highlighting synthetic options realization strong preferences.

Language: Английский

Citations

20
Revealing the active Cu species in Cu/ZSM-5 catalysts for the selective catalytic oxidation of ammonia DOI

Sein Hwang,

Dong Chan Park,

Hyeongdong Jung

et al.

Catalysis Today, Journal Year: 2025, Volume and Issue: unknown, P. 115244 - 115244

Published: Feb. 1, 2025

Language: Английский

Citations

2
Influence of solvent structure and hydrogen bonding on catalysis at solid–liquid interfaces DOI
David S. Potts, Daniel T. Bregante, Jason S. Adams

et al.

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(22), P. 12308 - 12337

Published: Jan. 1, 2021

A pedagogical review that deconvolutes the excess free energy effects of several solvent phenomena and connects findings across a variety catalytic reactions materials.

Language: Английский

Citations

105
Condition-Dependent Pd Speciation and NO Adsorption in Pd/Zeolites DOI
Keka Mandal, Yuntao Gu, Karl S. Westendorff

et al.

ACS Catalysis, Journal Year: 2020, Volume and Issue: 10(21), P. 12801 - 12818

Published: Sept. 28, 2020

Metal ions exchanged on zeolites represent a unique bridge between heterogeneous solid materials and homogeneous inorganic chemistry. The complexing of metal with H2O or NO, is particular relevance for number reactions, including the ubiquitous presence both gases in pollution remediation technologies. Here, we interrogate molecular structure Pd cations SSZ-13 their interaction NO using experimental computational analyses. Density functional theory (DFT) spectroscopic characterization establish that preferentially populate two Al (2Al) sites six-membered ring as PdII. In situ kinetic analyses follow coordination environment reactivity function environmental conditions, structures are rationalized through ab initio dynamics first-principles thermodynamic modeling. Experiment modeling together reveal that, at temperatures <573 K, solvated mobilized by molecules, promoting catalytic CO oxidation, form complexes akin to analogues. Exposure promotes transformation from 2Al → 1Al charge-compensated H2O-solvated Pd-nitrosyl complexes, which desorb higher inhibit adsorption oxidation. A comparison Pd-BEA Pd-ZSM-5 demonstrates distribution Pd-NO under dry conditions coalesce into upon exposure H2O.

Language: Английский

Citations

93
Direct Propylene Epoxidation with Molecular Oxygen over Cobalt-Containing Zeolites DOI
Weijie Li, Guangjun Wu,

Wende Hu

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(9), P. 4260 - 4268

Published: Feb. 22, 2022

Direct propylene epoxidation with molecular oxygen is a dream reaction 100% atom economy, but aerobic challenging because of the undesired over-oxidation and isomerization epoxide products. Herein, we report construction uniform cobalt ions confined in faujasite zeolite, namely, Co@Y, which exhibits unprecedented catalytic performance propylene. Propylene conversion 24.6% achieved at oxide selectivity 57% 773 K, giving state-of-the-art production rate 4.7 mmol/gcat/h. The Co@Y very stable, no activity loss can be observed for over 200 h. Spectroscopic analyses reveal details activation on isolated ions, followed by interaction to produce epoxide, Co2+–Coδ+–Co2+ (2 < δ 3) redox cycle involved. pathway byproduct acrolein formation from investigated density functional theory calculations, unique interpreted. This work presents an explicit example constructing specific transition-metal within zeolite matrix toward selective oxidations.

Language: Английский

Citations

67
Inhibition Effect of Phosphorus Poisoning on the Dynamics and Redox of Cu Active Sites in a Cu-SSZ-13 NH3-SCR Catalyst for NOx Reduction DOI
Anqi Guo, Kunpeng Xie,

Huarong Lei

et al.

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(18), P. 12619 - 12629

Published: Sept. 12, 2021

Phosphorus (P) stemming from biodiesel and/or lubricant oil additives is unavoidable in real diesel exhausts and deactivates gradually the Cu-SSZ-13 zeolite catalyst for ammonia-assisted selective catalytic NOx reduction (NH3-SCR). Here, deactivation mechanism of by P-poisoning was investigated ex situ examination structural changes probing dynamics redox Cu active sites via a combination impedance spectroscopy, diffuse reflection infrared Fourier transform ultraviolet–visible spectroscopy. We unveiled that strong interactions between P led to not only loss turnovers but also restricted dynamic motion species during low-temperature NH3-SCR catalysis. Furthermore, CuII ↔ CuI cycling sites, especially → reoxidation half-cycle, significantly inhibited, which can be attributed disabling formation key dimeric intermediates. As result, activity at low temperatures (200 °C below) decreased slightly mildly poisoned considerably severely Cu-SSZ-13.

Language: Английский

Citations

63
Dynamic Evolution of Zeolite Framework and Metal-Zeolite Interface DOI

Zhong‐Pan Hu,

Jingfeng Han, Yingxu Wei

et al.

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(9), P. 5060 - 5076

Published: April 14, 2022

Zeolites and metal-zeolites are a class of porous materials that have been widely utilized in industry. So far, several fundamental questions relating to the dynamic evolution zeolite framework metal-zeolite interface remain unanswered. Contrary classical view zeolites as static, rigid, changeless material, atoms foreign metals can dynamically interconvert under pretreatment or reaction conditions, making it difficult identify real active centers mechanisms. With development characterization techniques theoretical calculations, more profound understanding at atomic scale has achieved. This critical Review will feature recent progress metal-zeolites, mainly focusing on T–O–T bonds breaking formation, metal valence state transformation, phase evolution, migration. We compare these proposed mechanisms analyze their suitability distinct experimental conditions. highlight identification sites catalytic mechanism should be cautious consider Finally, we summarize usages limitations different characteristic techniques, propose some future research directions about hope bridge gaps between knowledge achieved characterizations nature guide zeolite-based synthesis, modification, application.

Language: Английский

Citations

53