4.6 Article

CO oxidation activity enhancement of Ce0.95Cu0.05O2-δ induced by Pd co-substitution

Journal

CATALYSIS SCIENCE & TECHNOLOGY
Volume 6, Issue 22, Pages 8104-8116

Publisher

ROYAL SOC CHEMISTRY
DOI: 10.1039/c6cy00981f

Keywords

-

Funding

  1. Mintek
  2. Department of Science and Technology (Advanced Metals Initiative program)

Ask authors/readers for more resources

A bimetallic, ionic, Ce0.93Pd0.02Cu0.05O2-delta catalyst was synthesized in one step using a urea-assisted solution combustion method. The structural and electronic properties of the catalyst were studied by different techniques together with those of mono-metallic analogues. The catalytic performance of the materials was investigated using CO oxidation as the model exhaust reaction and the nature of the active sites was examined by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). X-ray diffraction (XRD), Raman spectroscopy, XPS, XANES, EXAFS and high resolution transmission electron microscopy (HR-TEM) revealed that the prepared materials are single-phase, solid-solution oxides with a fluorite structure. In situ XRD studies showed that the prepared materials are metastable up to 1100 degrees C. The correlation of the characterization and catalytic results indicates that catalytic performance is influenced by the presence of oxygen vacancies and the existence of synergism between Pd2+, Cu2+ and cerium ions. DRIFTS results revealed that CO interacts with the active centres already at room temperature, forming Cu+ and Pd2+ carbonyls.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.6
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

Article Materials Science, Multidisciplinary

Exploring the role of fuel on the microstructure of VOx/MgO powders prepared using solution combustion synthesis

Pinkie Ntola, Holger B. Friedrich, Abdul S. Mahomed, Ezra J. Olivier, Alisa Govender, Sooboo Singh

Summary: This study presents the structural characterization of VOx/MgO powders prepared by a stoichiometric solution combustion synthesis using five different fuels. The synthesized powders were characterized using X-ray diffraction, Raman spectroscopy, Inductively Coupled Plasma Emission Spectroscopy, Scanning Electron Microscopy, and Aberration Corrected Transmission Electron Microscopy. The results showed that the selection of fuel influenced the microstructure, vanadate phase formation, and dispersion of each powder. By correlating experimental microstructural parameters with calculated thermodynamic parameters, the study demonstrates the crucial role of fuel in controlling reaction kinetics.

MATERIALS CHEMISTRY AND PHYSICS (2022)

Article Chemistry, Physical

Phase evolution in thermally annealed Ni/Bi multilayers studied by X-ray absorption spectroscopy

Bidyadhar Das, Madhusmita Sahoo, Abhilash Patra, Ashok K. Yadav, S. N. Jha, Prasanjit Samal, Kartik Senapati, Pratap K. Sahoo

Summary: This study explores the feasibility of using X-ray Absorption Spectroscopy (XAS) to track changes in the local bonding environment in NiBi3 and NiBi systems. The decomposition of NiBi3 into NiO and Bi during thermal annealing was successfully tracked through changes in structural and magnetization behavior, which correlated well with the findings from XAS. The study also revealed that NiO becomes the dominant phase at 500 degrees C annealing temperature, as confirmed by magnetic hysteresis measurements and XAS.

PHYSICAL CHEMISTRY CHEMICAL PHYSICS (2022)

Article Crystallography

A new polymorph of 1-(4-nitrophenyl)-1H-benzimidazole (C13H9N3O2)

Halliru Ibrahim, Sizwe J. Zamisa, Muhammad D. Bala, Holger B. Friedrich

Summary: This passage describes the crystal structure parameters and related numerical values of a molecule, including its lattice parameters, cell volume, space group, etc.

ZEITSCHRIFT FUR KRISTALLOGRAPHIE-NEW CRYSTAL STRUCTURES (2022)

Article Chemistry, Multidisciplinary

Synthesis and Characterization of Ag/Al2O3 Catalysts for the Hydrogenation of 1-Octyne and the Preferential Hydrogenation of 1-Octyne vs 1-Octene

Revana Chanerika, Mzamo L. Shozi, Holger B. Friedrich

Summary: In this study, catalysts with different silver loadings supported on alumina were prepared and characterized. It was found that the catalysts with different silver loadings had different sizes of metal nanoparticles. In the competitive hydrogenation reaction, nanoparticles with sizes of 10-15 nm showed high conversion and stable operation. The performance of the catalysts was influenced by both the metal and support, with the support playing an important role in the overall acidity of the catalysts.

ACS OMEGA (2022)

Article Chemistry, Multidisciplinary

Microwave-Assisted Coprecipitation Synthesis and Local Structural Investigation on NiO, β-Ni(OH)2/Co3O4 Nanosheets, and Co3O4 Nanorods Using X-ray Absorption Spectroscopy at Co-Ni K-edge and Synchrotron X-ray Diffraction

Umesh P. Gawai, Shilpa D. Kamble, Sanjay K. Gurav, Manvendra N. Singh, Ashok K. Yadav, Shambhu N. Jha, Niranjan P. Lalla, Milind R. Bodke, Mahendra D. Shirsat, Babasaheb N. Dole

Summary: In this study, nanosheets of NiO and β-Ni(OH)(2)/Co3O4, as well as nanorods of Co3O4, were successfully synthesized on a large scale using microwave-assisted chemical coprecipitation method under low temperature and atmospheric pressure. The electronic and atomic structural properties of the samples were characterized using X-ray absorption spectroscopy (XAS), synchrotron X-ray diffraction (SXRD), Raman spectroscopy, FTIR, transmission electron microscopy (TEM), and UV-visible spectroscopy.

ACS OMEGA (2022)

Article Crystallography

Crystal structure of 3,3′-(pyridine-2,6-diylbis(methylene))bis(1-propyl-1H-imidazol-3-ium) ditetrafluoroborate, C19H27B2F8N5

David O. Ywaya, Holger B. Friedrich, Muhammad D. Bala, Lynette Soobramoney, Halliru Ibrahim

Summary: This article describes the crystal structure of compound C19H27N5. The compound crystallizes in the orthorhombic Pbca (no. 61) space group with lattice parameters of a = 9.8515(12) angstrom, b = 16.508(2) angstrom, c = 29.817(3) angstrom. Important physical parameters such as V = 4849.3(10) angstrom^3, Z = 8, R-gt(F) = 0.0409, and wR(ref)(F-2) = 0.1082 are also provided.

ZEITSCHRIFT FUR KRISTALLOGRAPHIE-NEW CRYSTAL STRUCTURES (2022)

Article Chemistry, Physical

The Effect of Coating Pd/Al2O3 and PdAg/Al2O3 Catalysts with [BMIM][DCA] for the Selective Hydrogenation of 1-Octyne in 1-Octene

Revana Chanerika, Mzamo L. Shozi, Mirko Prato, Holger B. Friedrich

Summary: This study investigated the selective hydrogenation of a mixed 1-octyne/1-octene feed using solid catalysts with an ionic liquid layer (SCILLs). Results showed that coating the catalysts with an ionic liquid layer increased the yield of 1-octene and maintained stability during the experiments.

CHEMCATCHEM (2023)

Article Chemistry, Multidisciplinary

Reaction-Diffusion-Driven Stoichiometric Gradient in Coevaporated Superconducting NiBi3 Thin Films

Bidyadhar Das, Tapas Ranjan Senapati, Ashok Kumar Yadav, G. R. Umapathy, Sambhu Nath Jha, Kartik Senapati, Pratap Kumar Sahoo

Summary: This article explores the dynamics involved in the formation of NiBi3 thin films using the codeposition method. By studying films grown at different evaporation rates of Bi, it is found that almost stoichiometric NiBi3 is formed only at the top surface, while a nonlinear stoichiometric variation occurs toward the substrate. The bonding environment around Ni, studied by X-ray absorption spectroscopy, agrees with the findings of RBS. The observed superconducting transition and magnetic coercivity are consistent with the ratio of Ni and Bi.

CRYSTAL GROWTH & DESIGN (2023)

Article Chemistry, Physical

Phase Transition of High-Surface-Area Glycol-Thermal Synthesized Lanthanum Manganite

Victor O. Anyanwu, Holger B. Friedrich, Abdul S. Mahomed, Sooboo Singh, Thomas Moyo

Summary: Cubic and rhombohedral phases of lanthanum manganite were synthesized using a high-pressure reactor. The synthesized LaMnO3, validated through X-ray diffraction, exhibited significant structural transformation from the cubic to the rhombohedral phase, resulting in changes in unit cell volumes. Transmission electron microscopy analysis confirmed small particle sizes, no agglomeration, and good crystallinity. The material's particle characteristics, high purity, and high surface area make it suitable for important technological applications, including the synthesis of perovskite oxides.

MATERIALS (2023)

Article Multidisciplinary Sciences

Morphology, oxygen vacancies, and other factors affecting the performance of supported bimetallic ceria catalysts

Majid D. Farahani, Cheslin Moodley, Abdul S. Mahomed, Holger B. Friedrich

Summary: In this study, a Pt-V/CeO2 catalyst was developed for amide hydrogenation under mild conditions. It was found that oxygen vacancies on the ceria surface play a crucial role in the catalytic activity, with the absence of oxygen vacancies enhancing the hydrogenation ability of Pt sites and promoting the in situ formation of oxophilic V3+.

ISCIENCE (2022)

Article Physics, Applied

Effect of Co doping on structural and magnetic properties of kagome like La based cuprate francisite Cu3La(SeO3)2O2Cl

P. Manna, S. Kanthal, Md. A. Ahmed, A. Banerjee, S. Adhikary, S. Kanungo, A. K. Yadav, S. N. Jha, D. Bhattacharyya, S. Bandyopadhyay

Summary: The effects of Co doping on the structural and magnetic properties of a rare earth based synthetic analog of mineral francisite have been investigated. Density functional theory calculations show that the studied compounds have strong antiferromagnetic nature. Co-doping at the Cu2+ site confirms incorporation of Co2+ with similar local environment. The observed meta-magnetic and spin reorientation transitions are explained by considering magnetic exchange interactions and competition among different intra-layer exchange interactions.

JOURNAL OF APPLIED PHYSICS (2023)

Article Materials Science, Coatings & Films

Investigation of the transition of amorphous Ti-thiolate prepared by hybrid atomic layer deposition/molecular layer deposition into titanium disulfide ultrathin film

Petros Abi Younes, Ashok-Kumar Yadav, Medet Zhukush, Van-Hoan Le, Herve Roussel, Marie-Ingrid Richard, Clement Camp, Kai Szeto, Gianluca Ciatto, Nathanaelle Schneider, Elsje Alessandra Quadrelli, Hubert Renevier, Nicolas Gauthier

Summary: Amorphous organic-inorganic hybrid thin films (Ti-thiolate) on thermal SiO2 substrate are converted into textured titanium disulfide (TiS2) ultrathin films through annealing under Ar/H-2 atmosphere. Two annealing strategies were investigated to control the mineralization process. The stoichiometry and crystallinity of the films were characterized by various techniques.

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A (2023)

Article Chemistry, Physical

The Effect of a Nitrogen-Based Ionic Liquid as a Coating over 1Pd9Ag/Al2O3 for the Selective Hydrogenation of 1,7-Octadiene vs 1-Octene

Revana Chanerika, Mzamo L. Shozi, Mirko Prato, Holger B. Friedrich

Summary: The effect of tetrabutylammonium nitrate as a surface coating over 1Pd9Ag/Al2O3 in the selective hydrogenation of 1,7-octadiene was studied. The results showed that the coating significantly decreased the conversion and selectivity of 1-octene. However, no net gain in 1-octene was observed. The thickness of the coating also affected the conversion and selectivity, with a thicker coating leading to further decline. Characterization of the catalysts confirmed leaching of the ionic liquid and re-establishment of the metal-support interaction.

CATALYSTS (2023)

Article Chemistry, Physical

In situ construction of a highly active surface interface for a Co3O4|ZrO2 catalyst enhancing the CO-PrOx activity

Lindokuhle B. Ngema, Majid D. Farahani, Shaine Raseale, Nico Fischer, Abdul S. Mohamed, Sooboo Singh, Holger B. Friedrich

Summary: Employing a reduction-oxidation pretreatment successfully modified the Co3O4 | ZrO2 catalyst surface, leading to improved CO oxidation activity. The restructuring of Co3O4 to CoO species on the ZrO2 surface formed a highly active Co3O4-CoO | ZrO2 interface, resulting in enhanced CO2 desorption sites and CO oxidation activity. The findings highlight the importance of surface modification for improving CO preferential oxidation activity.

SURFACES AND INTERFACES (2023)

Article Chemistry, Multidisciplinary

Synthesis and characterization of amine-functionalized supported phosphine catalysts and their application in ethylene oligomerization

Mzamo L. Shozi, Xolelwa Zulu, Holger B. Friedrich

Summary: A series of phosphorus and nitrogen-based ethylene oligomerization ligands were reported, characterized, and tested for activity and selectivity towards 1-octene. The supported catalysts showed comparable activity to their homogeneous counterparts, with high selectivities to 1-octene in the C8 products.

SOUTH AFRICAN JOURNAL OF CHEMISTRY-SUID-AFRIKAANSE TYDSKRIF VIR CHEMIE (2022)

Article Chemistry, Physical

Introducing carbon dots to NiFe LDH via a mild coprecipitation-aging method to construct a heterojunction for effective oxygen evolution

Zi-Ye Liu, Qian-Yu Wang, Ji-Ming Hu

Summary: In this study, a layered carbon dot composite catalyst (NiFe LDH@CDs) was prepared using a one-step coprecipitation method, without the need for heating or hydrothermal treatment. The CD-functionalized catalyst facilitated rapid charge transfer and accelerated the oxygen evolution reaction. Additionally, the heterojunction structure formed between NiFe LDH and CDs efficiently suppressed photoelectron-hole recombination.

CATALYSIS SCIENCE & TECHNOLOGY (2024)

Article Chemistry, Physical

A general and expedient amination of alcohols catalysed by a single-site (NN)Co(ii)-bidentate complex under solventless conditions

Rohit Kumar, Ankit Kumar Srivastava, Palaniyappan Nagarasu, Vedichi Madhu, Ekambaram Balaraman

Summary: We designed and synthesized a NN-CoII bidentate complex and used it for the amination of alcohols under mild and solventless conditions. The complex exhibited good reactivity towards both primary and sterically hindered secondary alcohols, providing high yields of amines. The pyrazole moiety in the ligand played a crucial role in the reaction. Furthermore, we demonstrated the reusability of the complex as a homogeneous cobalt catalyst.

CATALYSIS SCIENCE & TECHNOLOGY (2024)

Article Chemistry, Physical

Cu2O facet controlled reactivity for peroxidase-like activity

Shivanand Chettri, Liang-Ting Wu, Sagarmani Rasaily, Debesh Sharma, Bikram Gurung, Rajani Dewan, Sudarsan Tamang, Jyh-Chiang Jiang, Anand Pariyar

Summary: Replicating the enzymatic surface microenvironment in vitro is challenging, but constructing an analogous model could facilitate our understanding of surface effects and aid in developing an efficient bioinspired catalytic system. In this study, five unique Cu2O morphologies were generated, and the surface morphology variations were found to be a consequence of differences in the exposure of low-index facets. The reactivity of Cu2O was found to be influenced by the proportion of {110} planes, with r-Cu2O exhibiting the highest reactivity.

CATALYSIS SCIENCE & TECHNOLOGY (2024)

Article Chemistry, Physical

Defect-engineered Zr-MOFs with enhanced O2 adsorption and activation for photocatalytic H2O2 synthesis

Yong Tang, Jianhao Qiu, Dingliang Dai, Guanglu Xia, Lu Zhang, Jianfeng Yao

Summary: Defect engineering has been shown to improve the photocatalytic performance. This study investigated the use of defect-rich UiO-66-NH2 wrapped by ZnIn2S4 as a catalyst for photocatalytic H2O2 production. The defects in UiO-66-NH2 enhanced O-2 adsorption and charge separation, leading to higher H2O2 yield. The insights from this work can advance the research in defect engineering of MOFs and photocatalytic H2O2 synthesis.

CATALYSIS SCIENCE & TECHNOLOGY (2024)

Article Chemistry, Physical

Selective hydrogenation of amides and imides over heterogeneous Pt-based catalysts

Ruiyang Qu, Shuxin Mao, Jana Weiss, Vita A. Kondratenko, Evgenii V. Kondratenko, Stephan Bartling, Haifeng Qi, Annette-Enrica Surkus, Kathrin Junge, Matthias Beller

Summary: The hydrogenation of amides, a challenging reaction usually performed at high temperatures, has been achieved under milder conditions using a new Pt-MoOx/TiO2 catalyst. This catalyst system enables the selective hydrogenation of various amides and imides.

CATALYSIS SCIENCE & TECHNOLOGY (2024)

Article Chemistry, Physical

Intermetallic PdCu3 supported on nanodiamond-graphene for semi-hydrogenation of Phenylacetylene

Xiaoran Niu, Ao Wang, Lei Tong, Lei Wang, Yuan Kong, Chenliang Su, Hai-Wei Liang

Summary: This study introduces a novel intermetallic PdCu3 catalyst supported on defective nanodiamond-graphene (ND@G), which exhibits high selectivity (95%) and remarkable activity (turnover frequency: 2940 h(-1)), six times higher than that of the commercial Lindlar catalyst.

CATALYSIS SCIENCE & TECHNOLOGY (2024)

Review Chemistry, Physical

Strategies for the proton-coupled multi-electron reduction of CO2 on single-atom catalysts

Zhiyuan Zheng, Yiming Yue, Hongying Zhuo, Qinggang Liu, Yanqiang Huang

Summary: This review presents the recent research advances on single-atom catalysis for deep reduction of CO2. Detailed introductions and summaries were classified into three categories based on proton-coupled multi-electron transfer approaches: strengthening metal-support interaction, rational design and regulation of coordination environment, and development of SACs with multi-atom active sites. The challenges and future research directions in the field of SACs for CO2 reduction are also proposed.

CATALYSIS SCIENCE & TECHNOLOGY (2024)

Article Chemistry, Physical

Denitrogenation of tosylhydrazones: synthesis of aryl alkyl sulfones catalyzed by a phenalenyl-based molecule

Shiv Kumar, Paramita Datta, Anup Bhunia, Swadhin K. Mandal

Summary: This article reports a transition-metal-free process for in situ denitrogenation of tosylhydrazones, resulting in the production of various sulfones. The authors used a phenalenyl-based odd alternant hydrocarbon as a photoredox catalyst, which acted as a potent oxidant to facilitate the denitrogenation reaction. The method showed wide functional-group tolerance and high yields, making it suitable for late-stage modification of natural products.

CATALYSIS SCIENCE & TECHNOLOGY (2024)

Article Chemistry, Physical

Mechanistic insights into methanol carbonylation to methyl acetate over an efficient organic template-free Cu-exchanged mordenite

L. A. Luque-Alvarez, J. Gonzalez-Arias, F. Romero-Sarria, T. R. Reina, L. F. Bobadilla, J. A. Odriozola

Summary: Currently, the production of acetic acid through the carbonylation reaction of methanol has limitations, leading to the exploration of alternative methods using heterogeneous catalysts. This study investigates the methanol carbonylation reaction over a Cu-H-MOR catalyst and proposes a reaction mechanism based on the catalytic behavior and performance of the catalyst. The results provide insights into the reaction mechanism and the involvement of acid and redox centers.

CATALYSIS SCIENCE & TECHNOLOGY (2024)