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McCullagh AM, Gibson EK, Parker SF, Refson K, Lennon D. The adsorption of nitrobenzene over an alumina-supported palladium catalyst: an infrared spectroscopic study. Phys Chem Chem Phys 2023; 25:25993-26005. [PMID: 37729436 DOI: 10.1039/d3cp03028h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
As part of an on-going programme of development of an aniline synthesis catalyst suitable for operation at elevated temperatures, the geometry of the adsorption complex for nitrobenzene on a 5 wt% Pd/Al2O3 catalyst is investigated by infrared (IR) spectroscopy. Via an appreciation of the reduced site symmetry resulting from adsorption, application of the metal surface selection rule, and observation of in-plane modes only, the adsorption complex (Pd-nitrobenzene) at 28 °C is assigned as occurring vertically or tilted with respect to the metal surface, adopting Csσv(yz) symmetry. Moreover, adsorption occurs via a single Pd-O bond. Single molecule DFT calculations and simulated IR spectra assist vibrational assignments but indicate a parallel adsorption geometry to be energetically favourable. The contradiction between calculated and observed structures is attributed to the DFT calculations corresponding to an isolated molecule adsorption complex, while IR spectra relate to multi molecule adsorption that is encountered during sustained catalytic turnover. Residual hydrogen from the catalyst reduction stage leads to aniline formation on the Pd surface at low nitrobenzene coverages but, on increasing nitrobenzene exposure, the aniline is forced on to the alumina support. A reaction scheme is proposed whereby the nitrobenzene adsorption geometry is inherently linked to the high aniline selectivity observed for Pd/Al2O3 catalysts.
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Affiliation(s)
- Annelouise M McCullagh
- School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Emma K Gibson
- School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Stewart F Parker
- School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow, G12 8QQ, UK.
- ISIS Neutron and Muon Facility, STFC Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX, UK
| | - Keith Refson
- ISIS Neutron and Muon Facility, STFC Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX, UK
| | - David Lennon
- School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow, G12 8QQ, UK.
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Shaw M, Samanta D, Bera S, Mahto MK, Salam Shaik MA, Konar S, Mondal I, Dhara D, Pathak A. Role of Surface Oxygen Vacancies and Oxygen Species on CuO Nanostructured Surfaces in Model Catalytic Oxidation and Reductions: Insight into the Structure-Activity Relationship Toward the Performance. Inorg Chem 2022; 61:14568-14581. [PMID: 35914234 DOI: 10.1021/acs.inorgchem.2c01467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Defect engineering, such as modification of oxygen vacancy density, has been considered as an effective approach to tailor the catalytic performance on transition-metal oxide nanostructured surfaces. The role of oxygen vacancies (OV) on the surface of the as-prepared, zinnia-shaped morphology of CuO nanostructures and their marigold forms on calcination at 800 °C has been investigated through the study of model catalytic reactions of reduction of 4-nitrophenol and aerobic oxidation of benzyl alcohol. The OV on the surfaces of different morphologies of CuO have been identified and quantified through Rietveld analysis and HRTEM, EPR, and XPS studies. The structure-activity relationships between surface oxygen vacancies (OV) and catalytic performance have been systematically investigated. The enhanced catalytic performance of the cubic CuO nanostructures compared to their as-prepared forms has been attributed to the formation of surface oxygen species on the reactive and dominant (110) surface that has low oxygen vacancy formation energy. The mechanistic role of surface oxygen species in the studied reactions has been quantitatively correlated with the catalytic activity of the different morphological forms of the CuO nanostructures.
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Affiliation(s)
- Manisha Shaw
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Dipanjan Samanta
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Sharmita Bera
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Madhusudan Kr Mahto
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Md Abdus Salam Shaik
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Suraj Konar
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India.,Department of Chemistry, R.D. & D.J. College, Munger, Bihar 811201, India
| | - Imran Mondal
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Dibakar Dhara
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Amita Pathak
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
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Boronat M, Climent MJ, Concepción P, Díaz U, García H, Iborra S, Leyva-Pérez A, Liu L, Martínez A, Martínez C, Moliner M, Pérez-Pariente J, Rey F, Sastre E, Serna P, Valencia S. A Career in Catalysis: Avelino Corma. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01043] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mercedes Boronat
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
| | - Maria J. Climent
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
| | - Patricia Concepción
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
| | - Urbano Díaz
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
| | - Hermenegildo García
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
| | - Sara Iborra
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
| | - Antonio Leyva-Pérez
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
| | - Lichen Liu
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Agustin Martínez
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
| | - Cristina Martínez
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
| | - Manuel Moliner
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
| | - Joaquín Pérez-Pariente
- Instituto de Catálisis y Petroleoquímica, Consejo Superior de Investigaciones Científicas, Marie Curie 2, Madrid 28049, Spain
| | - Fernando Rey
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
| | - Enrique Sastre
- Instituto de Catálisis y Petroleoquímica, Consejo Superior de Investigaciones Científicas, Marie Curie 2, Madrid 28049, Spain
| | - Pedro Serna
- ExxonMobil Technology and Engineering Company, Catalysis Fundamentals, Annandale, New Jersey 08801, United States
| | - Susana Valencia
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, Valencia 46022, Spain
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Millán R, Soriano MD, Cerdá Moreno C, Boronat M, Concepción P. Combined Spectroscopic and Computational Study of Nitrobenzene Activation on Non-Noble Metals-Based Mono- and Bimetallic Catalysts. NANOMATERIALS 2021; 11:nano11082037. [PMID: 34443868 PMCID: PMC8398056 DOI: 10.3390/nano11082037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 12/22/2022]
Abstract
In this paper, substituted anilines are industrially obtained by direct hydrogenation of nitroaromatic compounds with molecular H2 using metals as catalysts. Previous theoretical studies proposed that the mechanism of the reaction depends on the nature of the metal used as a catalyst, and that rationally designed bimetallic materials might show improved catalytic performance. Herein, we present IR spectroscopic studies of nitrobenzene interactions with monometallic Ni/SiO2, Cu/SiO2 and Pd/SiO2, and with bimetallic CuNi/SiO2 and CuPd/SiO2 catalysts, both in the absence and presence of H2, combined with density functional theory (DFT) calculations on selected bimetallic NiCu(111) and PdCu(111) models. The results obtained experimentally confirm that the reaction mechanism on non-noble metals such as Ni proceeds through N-O bond dissociation, generating nitrosobenzene intermediates, while, on noble metals, such as Pd, H-attack is necessary to activate the NO bond. Moreover, a bimetallic CuPd/SiO2 catalyst with a Pd enriched surface is prepared that exhibits an enhanced H2 dissociation ability and a particular reactivity at the boundary between the two metals.
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