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Dynamic Evolution of Palladium Single Atoms on Anatase Titania Support Determines the Reverse Water–Gas Shift Activity

Journal Article · · Journal of the American Chemical Society
DOI:https://doi.org/10.1021/jacs.3c02326· OSTI ID:1984061
Research interest in single-atom catalysts (SACs) has been continuously rising. However, the lack of understanding of the dynamic behaviors of SACs during applications hinder catalyst development and mechanistic understanding. Herein, we report on the evolution of active sites over Pd/TiO2-anatase SAC (Pd1/TiO2) in the reverse water-gas shift (rWGS) reaction. Combining kinetics, in-situ characterization, and theory, we show that at T ≥ 350 °C, the reduction of TiO2 by H2 alters the coordination environment of Pd, creating Pd sites with partially cleaved Pd-O interfacial bonds and a unique electronic structure that exhibit high intrinsic rWGS activity through the carboxyl pathway. The activation by H2 is accompanied by the partial sintering of single Pd atoms (Pd1) into disordered, flat, ~1 nm diameter clusters (Pdn). The highly active Pd sites in the new coordination environment under H2 are eliminated by oxidation, which, when performed at high temperature, also re-disperses Pdn and facilitates the reduction of TiO2. In contrast, Pd1 sinters into crystalline, ~5 nm particles (PdNP) during CO treatment, deactivating Pd1/TiO2. During the rWGS reaction, the two Pd evolution pathways co-exist. The activation by H2 dominates, leading to the increasing rate with time-on-stream, and steady-state Pd active sites similar with the ones formed under H2. Finally, this work demonstrates how the coordination environment and nuclearity of metal sites on a SAC evolve during catalysis and pre-treatments, and how their activity is modulated by these behaviors. These insights on SAC dynamics and structure-function relationship are valuable to mechanistic understanding and catalyst design.
Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB)
Grant/Contract Number:
AC02-05CH11231; AC02-06CH11357; AC02-76SF00515; AC05-76RL01830
OSTI ID:
1984061
Alternate ID(s):
OSTI ID: 1986279
Report Number(s):
PNNL-SA-184358
Journal Information:
Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 19 Vol. 145; ISSN 0002-7863
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English

References (104)

Static Regulation and Dynamic Evolution of Single‐Atom Catalysts in Thermal Catalytic Reactions journal November 2018
Tailoring the Shape of Metal Ad-Particles by Doping the Oxide Support journal October 2011
Electronic Metal-Support Interactions in Single-Atom Catalysts journal March 2014
An Atomic-Scale View of CO and H 2 Oxidation on a Pt/Fe 3 O 4 Model Catalyst journal September 2015
Negative Charging of Au Nanoparticles during Methanol Synthesis from CO 2 /H 2 on a Au/ZnO Catalyst: Insights from Operando IR and Near‐Ambient‐Pressure XPS and XAS Measurements journal July 2019
In Situ Dispersion of Palladium on TiO 2 During Reverse Water–Gas Shift Reaction: Formation of Atomically Dispersed Palladium journal August 2020
Kinetics of H 2 Adsorption at the Metal–Support Interface of Au/TiO 2 Catalysts Probed by Broad Background IR Absorbance journal February 2021
Alkene Hydrosilylation on Oxide‐Supported Pt‐Ligand Single‐Site Catalysts journal May 2019
Influence of Hydrogen Pretreatment on the Structure of the Metal-Support Interface in Pt/Zeolite Catalysts journal December 1993
Effect of Various Pretreatments on the Structure and Properties of Ruthenium Catalysts journal June 1996
Nature of the metal-support interface in supported metal catalysts: Results from X-ray absorption spectroscopy journal January 1992
Catalytic hydrogenation of CO2 over supported palladium journal March 1986
An EXAFS study of platinum - oxygen bonds in the metal-support interface of a highly dispersed Pt/Al2O3 catalyst journal June 1985
On the intermediates of the acetic acid reactions on oxides: an IR study journal October 1996
Infrared study of CO adsorption on alumina supported palladium particles journal May 1998
The surface science of titanium dioxide journal January 2003
Oxide-catalyzed conversion of acetic acid into acetone: an FTIR spectroscopic investigation journal March 2003
Using probe molecule FTIR spectroscopy to identify and characterize Pt-group metal based single atom catalysts journal September 2017
Active sites and effects of H2O and temperature on the photocatalytic oxidation of 13C-acetic acid on TiO2 journal October 2005
Effects of single metal atom (Pt, Pd, Rh and Ru) adsorption on the photocatalytic properties of anatase TiO 2 journal December 2017
The synthesis of highly dispersed noble and base metals on silica via strong electrostatic adsorption: I. Amorphous silica journal December 2008
TAP reactor studies of the oxidizing capability of CO2 on a Au/CeO2 catalyst – A first step toward identifying a redox mechanism in the Reverse Water–Gas Shift reaction journal June 2013
CO2 hydrogenation on Au/TiC, Cu/TiC, and Ni/TiC catalysts: Production of CO, methanol, and methane journal November 2013
Kinetic modeling and transient DRIFTS–MS studies of CO2 methanation over Ru/Al2O3 catalysts journal November 2016
Synthesis of platinum single-site centers through metal-ligand self-assembly on powdered metal oxide supports journal September 2018
Steering the selectivity in CO2 reduction on highly active Ru/TiO2 catalysts: Support particle size effects journal September 2021
CO adsorption on oxide supported gold: from small clusters to monolayer islands and three-dimensional nanoparticles journal March 2004
Deciphering the Local Environment of Single-Atom Catalysts with X-ray Absorption Spectroscopy journal May 2021
Well-Defined Materials for Heterogeneous Catalysis: From Nanoparticles to Isolated Single-Atom Sites journal December 2019
Homogeneity of Surface Sites in Supported Single-Site Metal Catalysts: Assessment with Band Widths of Metal Carbonyl Infrared Spectra journal September 2016
Influence of CO on the Activation, O-Vacancy Formation, and Performance of Au/ZnO Catalysts in CO 2 Hydrogenation to Methanol journal June 2019
Heterolytic Hydrogen Activation: Understanding Support Effects in Water–Gas Shift, Hydrodeoxygenation, and CO Oxidation Catalysis journal April 2020
Controlling the O-Vacancy Formation and Performance of Au/ZnO Catalysts in CO2 Reduction to Methanol by the ZnO Particle Size journal July 2021
Temperature-Dependent Communication between Pt/Al2O3 Catalysts and Anatase TiO2 Dilutant: the Effects of Metal Migration and Carbon Transfer on the Reverse Water–Gas Shift Reaction journal September 2021
Disordered, Sub-Nanometer Ru Structures on CeO2 are Highly Efficient and Selective Catalysts in Polymer Upcycling by Hydrogenolysis journal April 2022
Mechanism of CO 2 Hydrogenation on Pd/Al 2 O 3 Catalysts: Kinetics and Transient DRIFTS-MS Studies journal September 2015
Influence of TiO 2 Bulk Defects on CO Adsorption and CO Oxidation on Au/TiO 2 : Electronic Metal–Support Interactions (EMSIs) in Supported Au Catalysts journal February 2017
Tuning the Selectivity of Single-Site Supported Metal Catalysts with Ionic Liquids journal September 2017
Beating Heterogeneity of Single-Site Catalysts: MgO-Supported Iridium Complexes journal March 2018
In Situ/Operando Techniques for Characterization of Single-Atom Catalysts journal February 2019
Understanding Heterolytic H 2 Cleavage and Water-Assisted Hydrogen Spillover on Fe 3 O 4 (001)-Supported Single Palladium Atoms journal July 2019
Gold Supported on Thin Oxide Films: From Single Atoms to Nanoparticles journal August 2008
Zeolite- and MgO-Supported Molecular Iridium Complexes: Support and Ligand Effects in Catalysis of Ethene Hydrogenation and H–D Exchange in the Conversion of H 2 + D 2 journal October 2011
Heterogeneous Catalysis on Atomically Dispersed Supported Metals: CO 2 Reduction on Multifunctional Pd Catalysts journal August 2013
CO 2 Reduction on Supported Ru/Al 2 O 3 Catalysts: Cluster Size Dependence of Product Selectivity journal October 2013
An extended x-ray absorption fine structure study of rhodium-oxygen bonds in a highly dispersed rhodium/aluminum oxide catalyst journal September 1985
Highly dispersed rhodium on alumina catalysts: influence of the atmosphere on the state and dispersion of rhodium journal March 1987
Structure of rhodium/titania in the normal and the SMSI state as determined by extended x-ray absorption fine structure and high-resolution transmission electron microscopy journal April 1988
Stabilization of metal ensembles at room temperature: palladium clusters in zeolites journal August 1989
Determination of IR extinction coefficients for linear- and bridged-bonded carbon monoxide on supported palladium journal August 1981
Structure of rhodium in an ultradispersed rhodium/alumina catalyst as studied by EXAFS and other techniques journal May 1985
Isolated Metal Active Site Concentration and Stability Control Catalytic CO 2 Reduction Selectivity journal February 2015
A Common Single-Site Pt(II)–O(OH) x – Species Stabilized by Sodium on “Active” and “Inert” Supports Catalyzes the Water-Gas Shift Reaction journal March 2015
Catalyst Architecture for Stable Single Atom Dispersion Enables Site-Specific Spectroscopic and Reactivity Measurements of CO Adsorbed to Pt Atoms, Oxidized Pt Clusters, and Metallic Pt Clusters on TiO 2 journal September 2017
H 2 Oxidation over Supported Au Nanoparticle Catalysts: Evidence for Heterolytic H 2 Activation at the Metal–Support Interface journal September 2018
Atomically Dispersed Pd on Nanodiamond/Graphene Hybrid for Selective Hydrogenation of Acetylene journal September 2018
Unlocking the Catalytic Potential of TiO 2 -Supported Pt Single Atoms for the Reverse Water–Gas Shift Reaction by Altering Their Chemical Environment journal June 2021
Spectroscopic Detection of Hydrogen Atom Spillover from Au Nanoparticles Supported on TiO 2 :  Use of Conduction Band Electrons journal January 2007
Effect of Surface Oxygen Vacancy on Pt Cluster Adsorption and Growth on the Defective Anatase TiO 2 (101) Surface journal November 2007
Adsorption and Photoinduced Decomposition of Acetone and Acetic Acid on Anatase, Brookite, and Rutile TiO 2 Nanoparticles journal July 2010
Hydrogen Adsorption and Diffusion on the Anatase TiO 2 (101) Surface: A First-Principles Investigation journal March 2011
Acetic Acid Adsorption on Anatase TiO 2 (101) journal May 2012
Reduced and n-Type Doped TiO 2 : Nature of Ti 3+ Species journal September 2009
Oxide- and Zeolite-Supported Isostructural Ir(C 2 H 4 ) 2 Complexes: Molecular-Level Observations of Electronic Effects of Supports as Ligands journal August 2012
Atmospheric formic and acetic acids: An overview journal May 1999
Dynamic formation of single-atom catalytic active sites on ceria-supported gold nanoparticles journal March 2015
Carbon monoxide-induced adatom sintering in a Pd–Fe3O4 model catalyst journal June 2013
Controlling selectivities in CO2 reduction through mechanistic understanding journal September 2017
Surpassing the single-atom catalytic activity limit through paired Pt-O-Pt ensemble built from isolated Pt1 atoms journal August 2019
Rh single atoms on TiO2 dynamically respond to reaction conditions by adapting their site journal October 2019
Structural evolution of atomically dispersed Pt catalysts dictates reactivity journal April 2019
Dynamic charge and oxidation state of Pt/CeO2 single-atom catalysts journal August 2019
A heterogeneous single-atom palladium catalyst surpassing homogeneous systems for Suzuki coupling journal June 2018
Bridging homogeneous and heterogeneous catalysis by heterogeneous single-metal-site catalysts journal June 2018
Tuning of catalytic sites in Pt/TiO2 catalysts for the chemoselective hydrogenation of 3-nitrostyrene journal September 2019
Carboxyl intermediate formation via an in situ-generated metastable active site during water-gas shift catalysis journal September 2019
Interface dynamics of Pd–CeO2 single-atom catalysts during CO oxidation journal June 2021
Phase stability frustration on ultra-nanosized anatase TiO2 journal June 2015
The effects of acetaldehyde, glyoxal and acetic acid on the heterogeneous reaction of nitrogen dioxide on gamma-alumina journal January 2016
Methanation of CO 2 and reverse water gas shift reactions on Ni/SiO 2 catalysts: the influence of particle size on selectivity and reaction pathway journal January 2015
Adatom surface diffusion of catalytic metals on the anatase TiO 2 (101) surface journal January 2017
Towards ALD thin film stabilized single-atom Pd 1 catalysts journal January 2016
Acetylene hydrochlorination using Au/carbon: a journey towards single site catalysis journal January 2017
Fabrication, characterization, and stability of supported single-atom catalysts journal January 2017
Atomically dispersed supported metal catalysts: perspectives and suggestions for future research journal January 2017
Reductant composition influences the coordination of atomically dispersed Rh on anatase TiO 2 journal January 2020
Ligand-coordinated Ir single-atom catalysts stabilized on oxide supports for ethylene hydrogenation and their evolution under a reductive atmosphere journal January 2021
Spectroscopic study of the interaction of carbon monoxide with cationic and metallic palladium in palladium–alumina catalysts journal January 1992
Spectroscopic study of CO adsorption on palladium–ceria catalysts journal January 1996
Thermodynamic analysis of phase stability of nanocrystalline titania journal January 1998
Estimation of mean size and shape of small metal particles by EXAFS journal January 1999
Surface chemistry of titania (anatase) and titania-supported catalysts journal January 1996
Energetics and diffusion of intrinsic surface and subsurface defects on anatase TiO[sub 2](101) journal January 2009
EXAFS Model of 2-Dimensional Platinum Clusters journal April 2013
Surface and subsurface oxygen vacancies in anatase TiO 2 and differences with rutile journal March 2009
Thermodynamic properties of Pt nanoparticles: Size, shape, support, and adsorbate effects journal December 2011
(Sub)Surface Mobility of Oxygen Vacancies at the TiO 2 Anatase (101) Surface journal September 2012
Crossover from Three-Dimensional to Two-Dimensional Geometries of Au Nanostructures on Thin MgO(001) Films: A Confirmation of Theoretical Predictions journal May 2007
Coordinatively Unsaturated Al3+ Centers as Binding Sites for Active Catalyst Phases of Platinum on  -Al2O3 journal September 2009
Isolated Metal Atom Geometries as a Strategy for Selective Heterogeneous Hydrogenations journal March 2012
Identification of active sites in CO oxidation and water-gas shift over supported Pt catalysts journal September 2015
Photochemical route for synthesizing atomically dispersed palladium catalysts journal May 2016
Thermally stable single-atom platinum-on-ceria catalysts via atom trapping journal July 2016
High-affinity adsorption leads to molecularly ordered interfaces on TiO 2 in air and solution journal August 2018