Controlling Heterogeneous Catalysis with Organic Monolayers on Metal Oxides.

ConspectusA key theme of heterogeneous catalysis research is achieving control of the environment surrounding the active site to precisely steer the reactivity toward desired reaction products. One method toward this goal has been the use of organic ligands or self-assembled monolayers (SAMs) on metal nanoparticles. Metal-bound SAMs are typically employed to improve catalyst selectivity but often decrease the reaction rate as a result of site blocking from the ligands. Recently, the use of metal oxide-bound organic modifiers such as organophosphonic acid (PA) SAMs has shown promise as an additional method for tuning reactions on metal oxide surfaces as well as modifying oxide-supported metal catalysts. In this Account, we summarize recent approaches to enhance catalyst performance with oxide-bound monolayers. These approaches include (1) modification of metal oxide catalysts to tune surface reactions, (2) formation of SAMs on the oxide component of supported metal catalysts to modify sites at the metal-support interface, and (3) enhancement of catalyst performance (e.g., stability) through modification of sites remote from the active sites.Both the headgroups and organic tail groups of PA SAMs or other ligands can influence reactions on metal oxide surfaces. Binding of the headgroup can selectively poison certain active sites, altering the selectivity in a manner analogous to metal-bound ligands (at the expense of active site quantity). Moreover, tail groups can be functionalized to interact favorably with reactants and intermediates, for instance through dipole-dipole interactions. On supported metal catalysts like Pt/Al2O3, PA SAMs can selectively form on the oxide support. This selective deposition allows for modification of the metal-support interface with minimal blockage of metal sites. PA headgroups were shown to provide tunable acid sites at the interface, dramatically improving hydrodeoxygenation rates of various alcohols. Additionally, organic tail functionality was used to activate or stabilize specific reactants at the interface, such as with the use of amine-functionalized PAs to stabilize chemisorption of CO2 during the reverse water gas shift reaction. PAs have also been found to affect the electronic properties of bulk metal sites through long-range electron withdrawal via the oxide, providing an additional avenue to tune catalytic behavior. Finally, organic modifiers were shown to enhance catalytic performance without directly modifying the active site. For instance, in biphasic liquid environments the modification of catalyst particles with hydrophobic or hydrophilic SAMs shifts the selectivity of multipath reactions on the basis of the hydrophobicities of different intermediates and products. As another "long-range" effect, the deposition of ligands on oxide supports improved catalyst stability through both improved resistance to sintering and suppression of active site poisoning. The recent contributions discussed in this Account demonstrate the versatility and significant potential for the approach of modifying catalysts with oxide-bound organic monolayers.

[1]  M. Coppens,et al.  Effect of External Surface Diffusion Barriers on Platinum/Beta‐Catalyzed Isomerization of n‐Pentane , 2021, Angewandte Chemie.

[2]  C. Farberow,et al.  Organic Modifiers Promote Furfuryl Alcohol Ring Hydrogenation via Surface Hydrogen-Bonding Interactions , 2021 .

[3]  P. Christopher,et al.  Enhancing sintering resistance of atomically dispersed catalysts in reducing environments with organic monolayers , 2021 .

[4]  Anlian Zhu,et al.  Light-switched reversible emulsification and demulsification of oil-in-water Pickering emulsions. , 2020, Angewandte Chemie.

[5]  Guozhu Zhang,et al.  Phosphonic acid modified ZnO nanowire sensors: Directing Reaction Pathway of Volatile Carbonyl Compounds. , 2020, ACS applied materials & interfaces.

[6]  J. Falconer,et al.  Tuning Gas Adsorption Selectivity and Diffusion Rates in Zeolites with Phosphonic Acid Monolayers , 2020 .

[7]  M. Janik,et al.  Control of molecular bonding strength on metal catalysts with organic monolayers for CO2 reduction. , 2020, Journal of the American Chemical Society.

[8]  D. K. Schwartz,et al.  Controlling Catalyst Phase Selectivity in Complex Mixtures with Amphiphilic Janus Particles. , 2019, ACS applied materials & interfaces.

[9]  C. Musgrave,et al.  Enhancing Au/TiO2 Catalyst Thermostability and Coking Resistance with Alkyl Phosphonic-Acid Self-Assembled Monolayers. , 2019, ACS applied materials & interfaces.

[10]  Xiaoqing Pan,et al.  Rh single atoms on TiO2 dynamically respond to reaction conditions by adapting their site , 2019, Nature Communications.

[11]  Jongmin Choi,et al.  A Short Review on Interface Engineering of Perovskite Solar Cells: A Self‐Assembled Monolayer and Its Roles , 2019, Solar RRL.

[12]  Lucas D. Ellis,et al.  Effects of Phosphonic Acid Monolayers on the Dehydration Mechanism of Aliphatic Alcohols on TiO2 , 2019, ACS Catalysis.

[13]  Guangxin Xie,et al.  Compartmentalization of Multiple Catalysts into Outer and Inner Shells of Hollow Mesoporous Nanospheres for Heterogeneous Multi-Catalyzed/Multi-Component Asymmetric Organocascade , 2019, ACS Catalysis.

[14]  F. Xia,et al.  Switching acidity on manganese oxide catalyst with acetylacetones for selectivity-tunable amines oxidation , 2019, Nature Communications.

[15]  Xue-qing Gong,et al.  Taming the stability of Pd active phases through a compartmentalizing strategy toward nanostructured catalyst supports , 2019, Nature Communications.

[16]  Peter N. Ciesielski,et al.  Phosphonic acid modifiers for enhancing selective hydrodeoxygenation over Pt catalysts: The role of the catalyst support , 2019, Journal of Catalysis.

[17]  D. K. Schwartz,et al.  Effects of metal oxide surface doping with phosphonic acid monolayers on alcohol dehydration activity and selectivity , 2019, Applied Catalysis A: General.

[18]  D. Resasco,et al.  Improving stability of cyclopentanone aldol condensation MgO-based catalysts by surface hydrophobization with organosilanes , 2018, Applied Catalysis B: Environmental.

[19]  D. K. Schwartz,et al.  Effect of Surface Hydrophobicity of Pd/Al2O3 on Vanillin Hydrodeoxygenation in a Water/Oil System , 2018, ACS Catalysis.

[20]  Joaquin Resasco,et al.  Approaches for Understanding and Controlling Interfacial Effects in Oxide-Supported Metal Catalysts , 2018, ACS Catalysis.

[21]  D. K. Schwartz,et al.  Phosphonic acid promotion of supported Pd catalysts for low temperature vanillin hydrodeoxygenation in ethanol , 2018, Applied Catalysis A: General.

[22]  Michael J. Janik,et al.  Interaction trends between single metal atoms and oxide supports identified with density functional theory and statistical learning , 2018, Nature Catalysis.

[23]  Tao Zhang,et al.  Heterogeneous single-atom catalysis , 2018, Nature Reviews Chemistry.

[24]  Carsten Sievers,et al.  Enhanced Hydrothermal Stability of γ-Al2O3 Catalyst Supports with Alkyl Phosphonate Coatings. , 2018, Langmuir : the ACS journal of surfaces and colloids.

[25]  D. K. Schwartz,et al.  Enhancing Cooperativity in Bifunctional Acid–Pd Catalysts with Carboxylic Acid-Functionalized Organic Monolayers , 2018 .

[26]  Jiping Ma,et al.  Carboxylic acid-modified metal oxide catalyst for selectivity-tunable aerobic ammoxidation , 2018, Nature Communications.

[27]  J. Dumesic,et al.  Solvent-enabled control of reactivity for liquid-phase reactions of biomass-derived compounds , 2018, Nature Catalysis.

[28]  Carsten Sievers,et al.  Control of interfacial acid–metal catalysis with organic monolayers , 2018, Nature Catalysis.

[29]  C. Musgrave,et al.  Controlling the Surface Reactivity of Titania via Electronic Tuning of Self-Assembled Monolayers , 2017 .

[30]  B. Puértolas,et al.  Hybrid Palladium Nanoparticles for Direct Hydrogen Peroxide Synthesis: The Key Role of the Ligand. , 2017, Angewandte Chemie.

[31]  J. Hensley,et al.  Bifunctional Catalysts for Upgrading of Biomass-Derived Oxygenates: A Review , 2016 .

[32]  Ping Liu,et al.  Inverse Oxide/Metal Catalysts in Fundamental Studies and Practical Applications: A Perspective of Recent Developments. , 2016, The journal of physical chemistry letters.

[33]  B. Binks,et al.  Compartmentalization of incompatible reagents within Pickering emulsion droplets for one-pot cascade reactions. , 2015, Journal of the American Chemical Society.

[34]  J. Warneke,et al.  Functionalization of platinum nanoparticles with L-proline: simultaneous enhancements of catalytic activity and selectivity. , 2015, Journal of the American Chemical Society.

[35]  S. Pang,et al.  Hydrogen exposure effects on Pt/Al₂O₃ catalysts coated with thiolate monolayers. , 2014, Langmuir : the ACS journal of surfaces and colloids.

[36]  D. K. Schwartz,et al.  Controlling the surface environment of heterogeneous catalysts using self-assembled monolayers. , 2014, Accounts of chemical research.

[37]  D. K. Schwartz,et al.  Control of metal catalyst selectivity through specific noncovalent molecular interactions. , 2014, Journal of the American Chemical Society.

[38]  Xiaohong Li,et al.  Carbon-supported bimetallic Pd–Fe catalysts for vapor-phase hydrodeoxygenation of guaiacol , 2013 .

[39]  Dhrubojyoti D. Laskar,et al.  Pathways for biomass‐derived lignin to hydrocarbon fuels , 2013 .

[40]  D. K. Schwartz,et al.  Controlling surface crowding on a Pd catalyst with thiolate self-assembled monolayers , 2013 .

[41]  R. Lobo,et al.  Bimetallic effects in the hydrodeoxygenation of meta-cresol on γ-Al2O3 supported Pt–Ni and Pt–Co catalysts , 2012 .

[42]  N. Zheng,et al.  Selective hydrogenation of α,β-unsaturated aldehydes catalyzed by amine-capped platinum-cobalt nanocrystals. , 2012, Angewandte Chemie.

[43]  D. K. Schwartz,et al.  Adsorption of oxygenates on alkanethiol-functionalized Pd(111) surfaces: mechanistic insights into the role of self-assembled monolayers on catalysis. , 2011, Langmuir : the ACS journal of surfaces and colloids.

[44]  M. Sakamoto,et al.  Corrosion resistant performances of alkanoic and phosphonic acids derived self-assembled monolayers on magnesium alloy AZ31 by vapor-phase method. , 2011, Langmuir : the ACS journal of surfaces and colloids.

[45]  Ute Zschieschang,et al.  Mixed Self‐Assembled Monolayer Gate Dielectrics for Continuous Threshold Voltage Control in Organic Transistors and Circuits , 2010, Advanced materials.

[46]  Juan Carlos Serrano-Ruiz,et al.  Conversion of cellulose to hydrocarbon fuels by progressive removal of oxygen , 2010 .

[47]  D. K. Schwartz,et al.  Controlled selectivity for palladium catalysts using self-assembled monolayers. , 2010, Nature materials.

[48]  A. F. Oliveira,et al.  Self-assembled Monolayers of Alkylphosphonic Acids on Aluminum Oxide Surfaces – A Theoretical Study , 2010 .

[49]  Daniel E. Resasco,et al.  Solid Nanoparticles that Catalyze Biofuel Upgrade Reactions at the Water/Oil Interface , 2010, Science.

[50]  A. Ulman,et al.  Formation and Structure of Self-Assembled Monolayers. , 1996, Chemical reviews.

[51]  D. K. Schwartz,et al.  Mechanisms and kinetics of self-assembled monolayer formation. , 2001, Annual review of physical chemistry.