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Ga speciation in Ga/H-ZSM-5 by in-situ transmission FTIR spectroscopy

Journal Article · · Journal of Catalysis
 [1];  [2];  [2];  [2];  [3]
  1. Univ. of Delaware, Newark, DE (United States); University of Delaware
  2. Univ. of Delaware, Newark, DE (United States)
  3. Univ. of Delaware, Newark, DE (United States); Peking Univ., Beijing (China)
H-ZSM-5 supported Ga (Ga/H-ZSM-5) has long been recognized as a promising catalyst for nonoxidative dehydrogenation and dehydroaromatization of alkanes. However, Ga speciation under reaction conditions remains controversial. In this work, in-situ transmission Fourier Transform infrared (FTIR) spectroscopy is employed to systematically investigate Ga speciation in Ga/H-ZSM-5 with three Si/Al ratios (15, 28 and 39) and a wide range of Ga/Al ratios (0–1.7). Quantitative FTIR spectroscopy with pyridine reveals that one Ga atom roughly replaces one Brønsted acid site (BAS) at Ga/BAS ratio up to 0.7, however, only up to ~80% of the BAS on the H-ZSM-5 can be exchanged even with excess amounts of Ga. At a low Si/Al ratio of 15, the intensity of GaHx bands on reduced Ga/H-ZSM-5 at 550 °C increases almost linearly at low Ga loadings (Ga/Al < 0.13), and then levels off. In contrast, no detectable GaHx bands are observed on Ga/H-ZSM-5 with a high Si/Al ratio of 39, with Ga/Al ratios up to 1.3. The dependence of GaHx bands on both the Si/Al ratios and the Ga/Al ratios shows that Ga speciation varies with BAS density in the zeolite. We hypothesize that paired BAS sites are preferentially exchanged with Ga+, leading to the formation of Ga+–H+ pair sites, while the exchange of isolated BAS form isolated Ga+ species. Using water as a probe molecule, we show that isolated Ga+ and Ga+–H+ pair sites have distinct properties, i.e., the former can be easily oxidized by water at 150 °C to form GaOOH species, while the latter is inactive under the same conditions. Furthermore, these results provide direct experimental evidence for the existence of two types of Ga species on reduced Ga/H-ZSM-5, highlighting the possibility that they have different catalytic activities in alkane dehydrogenation reactions.
Research Organization:
Univ. of Delaware, Newark, DE (United States)
Sponsoring Organization:
USDOE; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Advanced Manufacturing Office
Grant/Contract Number:
EE0007888
OSTI ID:
1861078
Alternate ID(s):
OSTI ID: 1775871
Journal Information:
Journal of Catalysis, Journal Name: Journal of Catalysis Vol. 393; ISSN 0021-9517
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (46)

Hydroxyl-Mediated Non-oxidative Propane Dehydrogenation over VO x /γ-Al 2 O 3 Catalysts with Improved Stability journal May 2018
The Chemical State of Gallium in Working Alkane Dehydrocyclodimerization Catalysts. In situ Gallium K-Edge X-Ray Absorption Spectroscopy journal March 1993
In situ Ga K edge XANES study of the activation of Ga/ZSM-5 prepared by chemical vapor deposition of trimethylgallium journal May 2005
The Nature of the Isolated Gallium Active Center for Propane Dehydrogenation on Ga/SiO2 journal March 2017
Maximizing propylene production via FCC technology journal March 2015
Characterization of Ga/HZSM-5 and Ga/HMOR synthesized by chemical vapor deposition of trimethylgallium journal October 2003
DRIFTS study of the chemical state of modifying gallium ions in reduced Ga/ZSM-5 prepared by impregnationI. Observation of gallium hydrides and application of CO adsorption as a molecular probe for reduced gallium ions journal October 2004
Gallium oxide nanorods by the conversion of gallium oxide hydroxide nanorods journal July 2007
DRIFTS study of the nature and chemical reactivity of gallium ions in Ga/ZSM-5II. Oxidation of reduced Ga species in ZSM-5 by nitrous oxide or water journal July 2005
Characterization and reactivity of Ga+ and GaO+ cations in zeolite ZSM-5 journal April 2006
Effect of liquid water on acid sites of NaY: An in situ liquid phase spectroscopic study journal October 2016
Propane dehydrogenation catalyzed by gallosilicate MFI zeolites with perturbed acidity journal January 2017
Cooperativity of adjacent Brønsted acid sites in MFI zeolite channel leads to enhanced polarization and cracking of alkanes journal May 2017
Catalytic properties of Ga-containing MFI-type zeolite in cyclohexane dehydrogenation and propane aromatization journal September 2018
γ-Al2O3 sheet-stabilized isolate Co2+ for catalytic propane dehydrogenation journal January 2020
Ultrasmall Co confined in the silanols of dealuminated beta zeolite: A highly active and selective catalyst for direct dehydrogenation of propane to propylene journal March 2020
Controlling the Isolation and Pairing of Aluminum in Chabazite Zeolites Using Mixtures of Organic and Inorganic Structure-Directing Agents journal March 2016
Cobalt-Catalyzed C–H Activation journal December 2015
Computational Modeling of the Nature and Role of Ga Species for Light Alkane Dehydrogenation Catalyzed by Ga/H-MFI journal May 2018
Characterization of Isolated Ga 3+ Cations in Ga/H-MFI Prepared by Vapor-Phase Exchange of H-MFI Zeolite with GaCl 3 journal May 2018
Temperature-Programmed Desorption of Pyridine on Zeolites in the Presence of Liquid Solvents journal August 2018
Nature and Catalytic Properties of In-Situ-Generated Brønsted Acid Sites on NaY journal December 2018
Highly Effective Propane Dehydrogenation Using Ga–Rh Supported Catalytically Active Liquid Metal Solutions journal September 2019
Molecular-Level Proximity of Metal and Acid Sites in Zeolite-Encapsulated Pt Nanoparticles for Selective Multistep Tandem Catalysis journal December 2019
Unraveling the Origins of the Synergy Effect between ZrO 2 and CrO x in Supported CrZrO x for Propene Formation in Nonoxidative Propane Dehydrogenation journal December 2019
Catalytic Dehydrogenation of Light Alkanes on Metals and Metal Oxides journal August 2014
Structure and Reactivity of Zn-Modified ZSM-5 Zeolites: The Importance of Clustered Cationic Zn Complexes journal December 2011
Catalysts for Production of Lower Olefins from Synthesis Gas: A Review journal August 2013
Shape-Controllable Synthesis and Morphology-Dependent Luminescence Properties of GaOOH:Dy 3+ and β-Ga 2 O 3 :Dy 3+ journal January 2010
Effects of Si/Al Ratio on the Distribution of Framework Al and on the Rates of Alkane Monomolecular Cracking and Dehydrogenation in H-MFI journal December 2013
Quantitatively Probing the Al Distribution in Zeolites journal May 2014
Lewis–Brønsted Acid Pairs in Ga/H-ZSM-5 To Catalyze Dehydrogenation of Light Alkanes journal February 2018
Selective and Stable Non-Noble-Metal Intermetallic Compound Catalyst for the Direct Dehydrogenation of Propane to Propylene journal October 2018
Zeolite-Encapsulated Pt Nanoparticles for Tandem Catalysis journal September 2018
Mechanism and Kinetics of Propane Dehydrogenation and Cracking over Ga/H-MFI Prepared via Vapor-Phase Exchange of H-MFI with GaCl 3 journal December 2018
Cooperative and Competitive Occlusion of Organic and Inorganic Structure-Directing Agents within Chabazite Zeolites Influences Their Aluminum Arrangement journal February 2020
In Situ X-ray Absorption Study of the Genesis and Nature of the Reduced Gallium Species in Ga/HZSM5 Catalysts journal February 2011
Size and Morphology Control of Gallium Oxide Hydroxide GaO(OH), Nano- to Micro-Sized Particles by Soft-Chemistry Route without Surfactant journal March 2008
Control of coordinatively unsaturated Zr sites in ZrO2 for efficient C–H bond activation journal September 2018
The effect of nitridation temperature on the structural, optical and electrical properties of GaN nanoparticles journal January 2014
Bulk binary ZrO 2 -based oxides as highly active alternative-type catalysts for non-oxidative isobutane dehydrogenation journal January 2016
Organometallic model complexes elucidate the active gallium species in alkane dehydrogenation catalysts based on ligand effects in Ga K-edge XANES journal January 2016
Silica-supported isolated gallium sites as highly active, selective and stable propane dehydrogenation catalysts journal January 2017
On the nature of gallium species in gallium-modified mordenite and MFI zeolites. A comparative DRIFT study of carbon monoxide adsorption and hydrogen dissociation journal January 2011
Synthesis of Gallium Oxide Hydroxide Crystals in Aqueous Solutions with or without Urea and Their Calcination Behavior journal June 2002
Light alkane dehydrogenation to light olefin technologies: a comprehensive review journal January 2015

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