DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Elucidating the Role of CO in the NO Storage Mechanism on Pd/SSZ-13 with in Situ DRIFTS

Journal Article · · Journal of Physical Chemistry. C
 [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Institute for Integrated Catalysis
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Institute for Integrated Catalysis; Washington State Univ., Pullman, WA (United States)

Pd ion exchanged zeolites emerged as promising materials for the adsorption and oxidation of air pollutants. For low-temperature vehicle exhaust, dispersed Pd ions are able to adsorb NOx even in H2O-rich exhaust in the presence of carbon monoxide. In order to understand this phenomenon, changes in Pd ligand environment have to be monitored in-situ. Herein, we directly observe the activation of hydrated Pd ion shielded by H2O into a carbonyl-nitrosyl complex Pd2+(NO)(CO) in SSZ-13 zeolite. The subsequent thermal desorption of ligands on Pd2+(NO)(CO) complex proceeds to nitrosyl Pd2+ rather than to carbonyl Pd2+ under various conditions. Thus, CO molecules act as additional ligands to provide alternative pathway through Pd2+(NO)(CO) complex with lower energy barrier for accelerating NO adsorption on hydrated Pd2+ ion, which is kinetically limited in the absence of CO. We further demonstrate that hydration of Pd ions in the zeolite is a prerequisite for CO-induced reduction of Pd ions to metallic Pd. The reduction of Pd ions by CO is limited under dry conditions even at a high temperature of 500°C, while water makes it possible at near RT. However, the primary NO adsorption sites are Pd2+ ions even in gases containing CO and water. These findings clarify additional mechanistic aspects of the passive NOx adsorption (PNA) process and will help extend the NOx adsorption chemistry in zeolite-based adsorbers to practical applications.

Research Organization:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
AC05-76RL01830
OSTI ID:
1842285
Report Number(s):
PNNL-SA--168814
Journal Information:
Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 3 Vol. 126; ISSN 1932-7447
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English

References (49)

Economizing on Precious Metals in Three‐Way Catalysts: Thermally Stable and Highly Active Single‐Atom Rhodium on Ceria for NO Abatement under Dry and Industrially Relevant Conditions** journal October 2020
Achieving Atomic Dispersion of Highly Loaded Transition Metals in Small-Pore Zeolite SSZ-13: High-Capacity and High-Efficiency Low-Temperature CO and Passive NO x Adsorbers journal November 2018
Palladium/Ferrierite versus Palladium/SSZ‐13 Passive NOx Adsorbers: Adsorbate‐Controlled Location of Atomically Dispersed Palladium(II) in Ferrierite Determines High Activity and Stability** journal December 2021
Investigations of the Dispersion of Pd in H-ZSM-5 journal December 1997
Structure, Distribution, and Properties of Co Ions in Ferrierite Revealed by FTIR, UV–Vis, and EXAFS journal September 2000
NO x uptake mechanism on Pt/BaO/Al2O3 catalysts journal November 2006
Low Temperature NO Storage of Zeolite Supported Pd for Low Temperature Diesel Engine Emission Control journal June 2016
Current Understanding of Cu-Exchanged Chabazite Molecular Sieves for Use as Commercial Diesel Engine DeNOx Catalysts journal August 2013
Comparison of NOx Adsorption/Desorption Behaviors over Pd/CeO2 and Pd/SSZ-13 as Passive NOx Adsorbers for Cold Start Application journal April 2019
Palladium/Zeolite Low Temperature Passive NOx Adsorbers (PNA): Structure-Adsorption Property Relationships for Hydrothermally Aged PNA Materials journal September 2019
An in situ Fourier transform infrared studyof zeolitic vibrations: Dehydration, deammoniation, and reammoniation of ion-exchanged Y zeolites journal March 1993
Oxidative redispersion of palladium and formation of PdO particles in NaY journal September 1989
On the hydrothermal stability of Cu/SSZ-13 SCR catalysts journal June 2018
Effect of reduction treatments (H2 vs. CO) on the NO adsorption ability and the physicochemical properties of Pd/SSZ-13 passive NOx adsorber for cold start application journal January 2019
Palladium/Beta zeolite passive NOx adsorbers (PNA): Clarification of PNA chemistry and the effects of CO and zeolite crystallite size on PNA performance journal January 2019
Mechanistic insight into the passive NOx adsorption in the highly dispersed Pd/HBEA zeolite journal January 2019
Activation of Pd/SSZ-13 catalyst by hydrothermal aging treatment in passive NO adsorption performance at low temperature for cold start application journal September 2017
Investigation of the active sites and optimum Pd/Al of Pd/ZSM–5 passive NO adsorbers for the cold-start application: Evidence of isolated-Pd species obtained after a high-temperature thermal treatment journal June 2018
Improving NOx storage and CO oxidation abilities of Pd/SSZ-13 by increasing its hydrophobicity journal November 2020
The superior hydrothermal stability of Pd/SSZ-39 in low temperature passive NOx adsorption (PNA) and methane combustion journal January 2021
Mechanistic insight in NO trapping on Pd/Chabazite systems for the low-temperature NOx removal from Diesel exhausts journal May 2021
Investigation of crystal size effect on the NOx storage performance of Pd/SSZ-13 passive NOx adsorbers journal August 2021
A comparative kinetics study between Cu/SSZ-13 and Fe/SSZ-13 SCR catalysts journal December 2015
Effect of sulfur aging and regeneration on low temperature NO adsorption over hydrothermally treated Pd/CeO 2 and Pd/Ce 0.58 Zr 0.42 O 2 catalysts journal November 2017
NOx uptake and release on Pd/SSZ-13: Impact Of Feed composition and temperature journal January 2021
Excellent activity and selectivity of Cu-SSZ-13 in the selective catalytic reduction of NOx with NH3 journal October 2010
Following the movement of Cu ions in a SSZ-13 zeolite during dehydration, reduction and adsorption: A combined in situ TP-XRD, XANES/DRIFTS study journal May 2014
Structural Interconversion between Agglomerated Palladium Domains and Mononuclear Pd(II) Cations in Chabazite Zeolites journal February 2021
Low-Temperature Pd/Zeolite Passive NO x Adsorbers: Structure, Performance, and Adsorption Chemistry journal July 2017
Molecular Level Understanding of How Oxygen and Carbon Monoxide Improve NO x Storage in Palladium/SSZ-13 Passive NO x Adsorbers: The Role of NO + and Pd(II)(CO)(NO) Species journal April 2018
Stabilization of Super Electrophilic Pd +2 Cations in Small-Pore SSZ-13 Zeolite journal December 2019
Theoretical and Spectroscopic Evidence of the Dynamic Nature of Copper Active Sites in Cu-CHA Catalysts under Selective Catalytic Reduction (NH 3 –SCR–NO x ) Conditions journal November 2020
Mobility of Cu Ions in Cu-SSZ-13 Determines the Reactivity of Selective Catalytic Reduction of NO x with NH 3 journal March 2021
Controlling Catalytic Selectivity Mediated by Stabilization of Reactive Intermediates in Small-Pore Environments: A Study of Mn/TiO 2 in the NH 3 -SCR Reaction journal September 2020
Condition-Dependent Pd Speciation and NO Adsorption in Pd/Zeolites journal September 2020
CH 4 Oxidation Activity in Pd and Pt–Pd Bimetallic Catalysts: Correlation with Surface PdO x Quantified from the DRIFTS Study journal April 2021
Synthesis, Modeling, and Catalytic Properties of HY Zeolite-Supported Rhodium Dinitrosyl Complexes journal August 2017
Onset of High Methane Combustion Rates over Supported Palladium Catalysts: From Isolated Pd Cations to PdO Nanoparticles journal March 2021
Mobility and Reactivity of Cu + Species in Cu-CHA Catalysts under NH 3 -SCR-NOx Reaction Conditions: Insights from AIMD Simulations journal September 2021
Regulation of the Dispersion of PdO through the Interaction with Acid Sites of Zeolite Studied by Extended X-ray Absorption Fine Structure journal October 2000
In-Situ QXAFS Studies on the Dynamic Coalescence and Dispersion Processes of Pd in the USY Zeolite journal September 2007
Dynamic in situ observation of rapid size and shape change of supported Pd nanoparticles during CO/NO cycling journal May 2007
Unraveling the mysterious failure of Cu/SAPO-34 selective catalytic reduction catalysts journal March 2019
Tuning Pt-CeO2 interactions by high-temperature vapor-phase synthesis for improved reducibility of lattice oxygen journal March 2019
Simple physical mixing of zeolite prevents sulfur deactivation of vanadia catalysts for NOx removal journal February 2021
The impact of automotive catalysis on the United Nations sustainable development goals journal July 2019
Uniform synthesis of palladium species confined in a small-pore zeolite via full ion-exchange investigated by cryogenic electron microscopy journal January 2021
Characterization of Cu-SSZ-13 NH3 SCR catalysts: an in situ FTIR study journal January 2013
On the Nature of Water Bound to a Solid Acid Catalyst journal February 1996