Article
Chemistry, Physical
Tshepo Molefe, Dean Barrett, Beatriz Diaz, Roy Forbes, Neil J. Coville
Summary: This study reports on the synthesis and application of osmium nanoparticles supported on and/or encapsulated in hollow carbon spheres for Fischer-Tropsch Synthesis (FTS). It is demonstrated that the interaction between osmium and cobalt has a significant effect on the catalyst activity when loaded together. Proximity of osmium and cobalt leads to higher FTS activity and C5+ production through the primary spillover effect. This study reveals the effect of osmium on FTS catalysts for the first time.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Tshepo Molefe, Roy P. Forbes, Neil J. Coville
Summary: The article discusses the use of osmium as a catalyst or promoter for Fischer Tropsch synthesis, with osmium nanoparticles supported on SiO2 or encapsulated inside hollow carbon spheres studied. The research shows that osmium primarily produces C(1) and C(2) hydrocarbons, but deactivates in the reaction, with osmium readily sintering on the supports under syngas, providing a deactivation pathway for the catalyst under FT conditions.
Article
Chemistry, Physical
Zhe Cai, Shuai Lyu, Yao Chen, Chengchao Liu, Yuhua Zhang, Faquan Yu, Jinlin Li
Summary: In this study, a series of catalysts with Co nanoparticles embedded in a matrix of porous carbon were directly synthesized using a unique melting approach. The catalyst showed high selectivity towards heavy hydrocarbons and low selectivity towards methane at a high operating temperature of 260 degrees C, with no obvious deactivation observed. The special carbon rich environment of the catalyst could inhibit the oxidization and agglomeration of the active phase, preventing deactivation.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Ceramics
Chunjian Xue, Jinlian Zhao, Yinpeng Liu, Xiying Li, Jiwei Zhang, Jingwei Zhang
Summary: The shell thickness of hollow carbon spheres (HCs) has a significant impact on the electrochemical performance due to its effect on lithium ion transport kinetics. A simple one-pot method was developed to synthesize Ndoped hollow carbon nanospheres (NHCs) with different shell thickness (6, 10, and 13 nm) while keeping other parameters almost the same. The NHCs-1 sample with a shell thickness of 6 nm exhibited higher initial charge capacity and better cycle stability compared to NHCs-2 and NHCs-3 with thicker shells of 10 nm and 13 nm, respectively. The capacity dependence on shell thickness was explained by changes in the mass transfer coefficient of Li-ion across the wall. The outstanding electrochemical properties of NHCs were attributed to their unique hollow structure, N-doping, and high specific surface area. The strategy for preparing hollow carbon spheres with different shell thickness provides a promising alternative for developing superior electrode materials for energy storage.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Physical
Tobias F. Kimpel, Jin-Xun Liu, Wei Chen, Robert Pestman, Emiel J. M. Hensen
Summary: Through IR spectroscopy and DFT calculations, it has been discovered that in the Fischer-Tropsch reaction, Mn promotes a silica-supported Co catalyst with a MnO layer covering the Co surface, activating adsorbed CO through reaction with an oxygen vacancy. This results in higher activity, higher CHx coverage, increased C5+ selectivity, and decreased CH4 selectivity. Increasing pressure amplifies the selectivity differences. However, above around 4 bar, the addition of Mn decreases C5+ selectivity, possibly due to its promotion of C-O bond dissociation but not chain growth. Migration of formed monomers for chain growth on the Co surface may be hindered by high CO coverage, especially at high pressure.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Shanhe Gong, Wenbo Wang, Xinxin Xiao, Jun Liu, Chundu Wu, Xiaomeng Lv
Summary: The study investigated the impact of CoPc existence formation on the CO2RR performance, revealing that the content of Co atom is the key factor determining the performance. The coexistence of crystals and evenly dispersed CoPc or evenly dispersed and low loading of CoPc can both achieve satisfying results within a certain range of Co atom content.
Article
Chemistry, Physical
Omid Akbarzadeh, Solhe F. Alshahateet, Noor Asmawati Mohd Zabidi, Seyedehmaryam Moosavi, Amir Kordijazi, Arman Amani Babadi, Nor Aliya Hamizi, Yasmin Abdul Wahab, Zaira Zaman Chowdhury, Suresh Sagadevan
Summary: In this study, the effect of reaction temperature, syngas space velocity, and catalyst stability on Fischer-Tropsch reaction using Co-Mn/CNT catalysts was investigated. Results showed that optimizing the temperature, space velocity, and H2/CO ratio led to increased CO conversion and C5+ selectivity. Additionally, the 95Co5Mn/CNT catalyst demonstrated better stability over 48 hours of continuous operation compared to other catalyst formulations.
Article
Chemistry, Physical
Mostafa Torkashvand, Saeedeh Sarabadani Tafreshi, Nora H. de Leeuw
Summary: The increasing demand for renewable fuels and sustainable products has led to the development of active and selective catalysts for the conversion of carbon monoxide. First-principles calculations based on density functional theory are used to investigate the Fischer-Tropsch synthesis over the Co (001) surface, revealing CH4 as the dominant product. Kinetic analysis shows that the hydrogenation of cis-HCOH has the lowest energy barrier for CH production, while the hydrogenation of CO to COH has the highest energy barrier.
Article
Chemistry, Applied
Sania Saheli, Ali Reza Rezvani, Azadeh Arabshahi, Michal Dusek, Erika Samolova, Marketa Jarosova
Summary: The preparation methods of two new catalysts for Fischer-Tropsch synthesis were studied, with the catalyst prepared via thermal decomposition showing higher activity due to its smaller particle size, better dispersion, and higher surface area. The catalyst obtained by impregnation method exhibited lower activity compared to the one prepared by thermal decomposition.
APPLIED ORGANOMETALLIC CHEMISTRY
(2021)
Article
Energy & Fuels
Wenli Lu, Jungang Wang, Zhongyi Ma, Congbiao Chen, Yan Liu, Bo Hou, Debao Li, Baojun Wang
Summary: The role of carbon deposits during Fischer-Tropsch synthesis (FTS) on cobalt catalysts is still debated. This study investigates the effects of pre-deposited composite and single carbon on cobalt catalysts in FTS. Different types of carbon deposits (atomic carbon, polymeric carbon, graphitic carbon) are identified and characterized using TPH, Raman, and XPS. Results show that the presence of pre-deposited carbon significantly affects the catalytic activity, methane selectivity, and stability of the Co-based catalysts in FTS.
Article
Chemistry, Physical
Yihua Tang, Xiao Wang, Jingjing Chen, Xinxin Wang, Dajian Wang, Zhiyong Mao
Summary: Highly nitrogen-doped hollow carbon spheres (HCSs) were successfully synthesized using solid graphitic carbon nitride (g-C3N4) precursor as carbon and nitrogen sources, showing promising lithium ion storage performances as anode materials in lithium ion batteries.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Rui Hu, Tianye Wang, Yifan Wang, Yuan Zhu, Li Xie, Enhui Xing, Yu Wu, Zhijian Da
Summary: A nano-hollow zeolite-encapsulating ultra-fine Fe nanoparticle catalyst, Fe@Sn-h-HT, was synthesized via water steam treatment of the Fe@Sn-h catalyst prepared by the dissolution-recrystallization (D-R) method. Fe@Sn-h-HT catalyst possessed a hierarchical porous structure and a well-dispersed Fe2O3 particles with a size of 3.4 nm. Additionally, characterization methods such as XRD, HAADF-STEM, and H-2-TPR confirmed the transformation of skeleton Fe in Fe@Sn-h into uniformly dispersed Fe2O3 in Fe@Sn-h-HT catalyst. The higher selectivity and yield of C-2-C-4(=) compared to reference catalysts Fe/S and Fe@Sn-h provided strong evidence for the confined catalysis of the metal@zeolite catalyst.
Article
Energy & Fuels
Jing Luo, Wen-Feng Zhang, Yan-Chen Wei, Ji-Xing Liu, Chao Wang, Yi-Ru Zou, Hai-Tao Ju, Li-Ping Mu, Yan-Hong Chao, Hong-Bing Ji, Wen-Shuai Zhu
Summary: In this study, basic nitrogen-doped carbon hollow spheres (p-N-C) catalysts derived from waste tires were prepared by a green and easy method for the catalytic oxidation of pentanethiol. The modified catalyst exhibited higher surface curvature and hierarchical porous structure, leading to enhanced catalytic performance. Nitrogen atoms on the carbon hollow spheres were found to accelerate the reaction and enhance the adsorption/oxidation process. The optimized p-N-C catalyst showed excellent catalytic activity, with higher adsorption and oxidation performance than the unmodified catalyst. This work provides a new avenue for the fabrication of highly efficient materials for fuel desulfurization.
Article
Chemistry, Physical
Amel Cydric Ghogia, Bruno F. Machado, Simon Cayez, Ange Nzihou, Philippe Serp, Katerina Soulantica, Doan Pham Minh
Summary: The chemistry between the Co precursor and the support during catalyst preparation has a crucial impact on the catalyst properties, while the CNT surface chemistry also influences the characteristics of the catalyst. The study found an inverse correlation between Co particle size and activity, highlighting the importance of precursor/support couple in the structure and performance of Co/CNT catalysts.
JOURNAL OF CATALYSIS
(2021)
Article
Engineering, Chemical
Min Zhao, Ziang Zhao, Yuan Lyu, Wei Lu, Ming Jin, Tao Liu, Hejun Zhu, Yunjie Ding
Summary: The appropriate metal-support interaction plays a crucial role in the supported Fischer-Tropsch catalysts. By synthesizing a series of porous spinel MAl2O4 together with Al2O3, and using them as supports for Co-based Fischer-Tropsch synthesis catalysts, the study investigated the influence of metal-support interaction on Co dispersity, reducibility, and catalytic performance. The results demonstrated that 15Co/CoAl2O4 showed the highest activity and C5+ selectivity due to weaker metal-support interaction, leading to higher reducibility and CO dissociation ability.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Engineering, Chemical
Chike George Okoye-Chine, Roy Forbes, Joshua Gorimbo, Mahluli Moyo, Xinying Liu, Diane Hildebrandt
Summary: The reduction pathway of Co catalysts supported on untreated SiO2 and two pretreated SiO2 support materials was investigated. The study revealed that ethylene glycol pretreated SiO2 supported Co catalyst showed smaller metal crystallites and highly dispersed Co, but had a low degree of reduction of CoO due to the strong Co-SiO2 interaction. In contrast, the annealing pretreated SiO2 supported Co catalyst exhibited better catalytic activity during FTS.
CHEMICAL ENGINEERING COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Ludwe L. Sikeyi, Laercia R. Bila, Themba D. Ntuli, Cyril T. Selepe, Nobanathi W. Maxakato, Neil J. Coville, Manoko S. Maubane-Nkadimeng
Summary: This study presents the synthesis of Pt supported on titania oxide nanoparticles decorated on sulfur doped onion-like carbon nanoparticles (S-OLCNs) and their application as electrocatalysts for ammonia oxidation reactions. The incorporation of TiO2 nanoparticles into Pt/S-OLCN was found to significantly enhance the activity of Pt for the ammonia oxidation reaction by facilitating the electron transfer process. Pt/TiO2/S-OLCN also exhibited better long term stability and faster charge transfer resistance compared to other catalysts tested.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Electrochemistry
B. Shaku, T. P. Mofokeng, N. J. Coville, K. I. Ozoemena, M. S. Maubane-Nkadimeng
Summary: This study presents the conversion of marula nutshell waste into nitrogen-doped activated carbon (N-ACs) for supercapacitor electrode material. The N-ACs demonstrated high surface area and porosity, resulting in excellent electrochemical performance in KOH and KNO3 electrolytes. The material achieved remarkable energy and power densities in 2.5 M KNO3 electrolyte, making it a promising energy storage material for supercapacitors.
ELECTROCHIMICA ACTA
(2023)
Article
Chemistry, Multidisciplinary
Ryan O'Connor, Joyce B. Matsoso, Victor Mashindi, Pumza Mente, Lebohang Macheli, Beatriz D. Moreno, Bryan P. Doyle, Neil J. Coville, Dean H. Barrett
Summary: In this study, the influence of counter anion on the structural properties of hollow carbon spheres (HCS) support was investigated. It was found that the thickness of the HCS shell depended on the type of nickel precursor salt used. The choice of precursor salt also affected the textural properties of the HCS nanosupports and influenced the growth of nickel nanoparticles.
Article
Food Science & Technology
Na Hu, Erjun Tang, Shuo Wang, Miao Yuan, Shaojie Liu, Xiaomeng Chu, Xuteng Xing, Xinying Liu, Linda Jewell
Summary: Different degrees of substitution were used to prepare Chestnut starch acetates (CSA). The characterization showed that CSA granules were damaged and dented, adhering to an increase in DS. CSA and CS had a crystal form of type C based on X-ray diffraction analysis. Chemical structure analysis indicated grafting of acetyl groups onto starch molecules. An increase in DS improved the transparency, freeze-thaw stability, solubility, and swelling power of CSA. CSA exhibited enhanced viscosity, stability, and reduced pasting temperatures compared to native CS. However, an increase in DS resulted in decreased cohesion, hardness, gumminess, chewiness, and springiness, but increased adhesiveness. These findings provide a new option for the application of CSA in food fields as a renewable natural polymer.
INTERNATIONAL JOURNAL OF FOOD ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Melisha Jivanji, Roy Peter Forbes, Humphrey Sithebe, Johan Ewald Westraadt
Summary: This study investigates the effect of ZrB2 additions on the microstructure, thermal stability, and thermo-mechanical wear resistance of polycrystalline diamond. The ZrB2-PCD material binder phase consisted of cobalt-boride phases. The ZrB2-PCD tools showed excellent thermo-mechanical wear resistance, but lowered abrasion wear resistance was observed during low-temperature wet-VTL testing.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2023)
Review
Optics
Orlette Mkhari, Themba D. Ntuli, Neil J. Coville, Edward N. Nxumalo, Manoko S. Maubane-Nkadimeng
Summary: Carbon dot/support nanocomposites exhibit improved properties and hold great potential for applications in fields such as photocatalysis, electrochemistry, optics, and nanomedicine.
JOURNAL OF LUMINESCENCE
(2023)
Article
Chemistry, Physical
Djalila Guettaia, Hanane Zazoua, Mohammed Reda Ramdani, Khaldoun Bachari, Neil J. Coville, Amel Boudjemaa
Summary: This paper reports on the photodegradation of ibuprofen (IBP) using SiO2@xTiO(2) synthesized via a hydrothermal method. The catalysts were prepared by adding TiO2 to a Stober synthesized silica at different weight loadings. The SiO2@xTiO(2) showed excellent photodegradation efficiency and the degradation rate of IBP increased with the formation of H2O2.
REACTION KINETICS MECHANISMS AND CATALYSIS
(2023)
Article
Food Science & Technology
Shuo Wang, Na Hu, Erjun Tang, Shenglan Yang, Xinying Liu, Linda Jewell
Summary: Porous phosphorylated chestnut starch (P-PCS) was prepared by enzymic hydrolysis and phosphorylation of chestnut starch (CS), and the phosphorylation conditions were optimized using response surface design. The optimal reaction conditions were a CP/P-CS mass ratio of 2:1, a reaction temperature of 146 degrees C, and a reaction time of 159 min. P-PCS exhibited improved light transmittance and Pb(II) adsorption performance compared to CS, indicating its potential as a natural polymer adsorbent in wastewater treatment.
Article
Chemistry, Multidisciplinary
Themba D. Ntuli, Ludwe L. Sikeyi, Faria Dziike, Neil J. Coville, Edward N. Nxumalo, Manoko S. Maubane-Nkadimeng
Summary: Waste cooking oil was converted into onion-like nanocarbons (OLNCs) through flame pyrolysis and then combined with TiO2 to form TiO2/OLNC nanocomposites using hydrothermal treatment. The mass ratio of TiO2 to OLNCs was varied, while the mass of TiO2 was kept constant. The nanocomposites exhibited enhanced photocatalytic activity and degradation efficiency for methyl orange due to the high adsorption efficiency of OLNCs and the hindrance of electron-hole recombination.
APPLIED SCIENCES-BASEL
(2023)
Review
Nanoscience & Nanotechnology
X. Cheng, C. Tang, C. Yan, J. Du, A. Chen, X. Liu, L. Jewell, Q. Zhang
Summary: In order to meet the energy storage needs of portable electronic devices, electric vehicles, renewable-coupled smart grids, and more, it is important to develop lithium-ion batteries (LIBs) with increased energy densities. Porous carbon spheres, with their high chemical stability, electrical conductivity, specific surface area, and porous structure, show promise as anode materials for LIBs. In this review, various preparation methods for porous carbon spheres are introduced, and strategies for improving the performance of LIBs anode materials are described.
MATERIALS TODAY NANO
(2023)
Review
Chemistry, Physical
Lerato L. Mokoloko, Roy P. Forbes, Neil J. Coville
Summary: Since their discovery in 2004, carbon dots (CDs) have been widely used in various applications due to their fluorescent properties. However, the potential uses of CDs as catalysts and supports in catalytic reactions are still relatively unexplored. Studies have shown the advantages of using CDs in catalysis, but there are challenges associated with their stability and aggregation due to their small size.
Article
Chemistry, Multidisciplinary
Saureille Ngouana Moafor, Patrice Kenfack Tsobnang, Kabir Oyeniran Oyedotun, Roussin Lontio Fomekong, Guy L. Kabongo, Macheli Lebohang, John Ngolui Lambi, Linda L. Jewell
Summary: This study investigates the effect of the SiO2/Al2O3 ratio on the electrochemical performance of the aluminum silicate/cobalt oxide composite. The results show that the specific capacity increases as the SiO2/Al2O3 ratio increases. It was also found that after 2000 cycles, Co/H-AZ(1) and Co/AZ(1) exhibit poor coulombic efficiency, while Co/H-AZ(2) and Co/AZ(2) exhibit a coulombic efficiency of 98%.
Article
Chemistry, Multidisciplinary
Lerato L. Mokoloko, Roy P. Forbes, Neil J. Coville
Summary: In this study, solid hydrophobic carbon dots and carbon spheres were synthesized directly using a vertical chemical vapour deposition reactor. The carbon dots and carbon spheres were found to originate from different carbon building blocks. The carbon dots were obtained through the reaction of acetylene and Ar mixtures at high flow rates and temperatures, while the carbon spheres were synthesized through a different pathway and had a typical spherical layered structure without a graphitic core.
SOUTH AFRICAN JOURNAL OF CHEMISTRY-SUID-AFRIKAANSE TYDSKRIF VIR CHEMIE
(2022)
Article
Chemistry, Multidisciplinary
Thomas H. Mongwe, Themba D. Ntuli, Ludwe L. Sikeyi, Neil J. Coville, Messai A. Mamo, Jose P. M. Serbena, Manoko S. Maubane-Nkadimeng
Summary: This study reports on the synthesis of carbon nano-onions and nitrogen-doped carbon nano-onions, and their application in gas sensing materials. The results showed that the composite based on pristine CNOs exhibited higher sensitivity to acetone, while the sensor based on N-CNOs had a lower limit of detection.
SOUTH AFRICAN JOURNAL OF CHEMISTRY-SUID-AFRIKAANSE TYDSKRIF VIR CHEMIE
(2022)
Article
Chemistry, Applied
Qingyuan Zheng, Jack H. Williams, Scott Elgersma, Mick D. Mantle, Andrew J. Sederman, G. Leendert Bezemer, Constant M. Guedon, Lynn F. Gladden
Summary: In this study, a pilot-scale fixed-bed reactor compatible with NMR/MRI was developed for Fischer-Tropsch synthesis. Multiple magnetic resonance techniques were applied to quantitatively characterize different product species within catalyst pellets, providing valuable information for catalyst and reactor optimization.
Article
Chemistry, Applied
Lisa Ramisch, Sebastian Pfaff, Sabrina M. Gericke, Edvin Lundgren, Johan Zetterberg
Summary: We present a combination of optical operando techniques that allow simultaneous measurement of adsorbed species on catalyst surfaces, monitoring of surface oxide formation, and imaging of the gas phase above the catalyst surface. The experimental setup was validated by studying CO oxidation on Pd(100) at different pressures, revealing the effects of pressure on the heterogeneous catalytic reaction.
Article
Chemistry, Applied
Marta Paniagua, Gabriel Morales, Juan A. Melero, Daniel Garcia-Salgado
Summary: The influence of common impurities in levulinic acid on the catalytic performance of different acid catalysts for bio-jet fuel production was studied. It was found that furfural had the greatest detrimental effect on catalyst performance, while propyl-sulfonic acid-modified SBA-15 and sulfonic acid resin Amberlyst-70 showed good regeneration ability.
Article
Chemistry, Applied
Jesus Tapiador, Pedro Leo, Guillermo Calleja, Gisela Orcajo
Summary: This study presents a new MOF material, Zn-URJC-13, with acid and basic sites, permanent porosity, and high affinity to CO2 molecules. The Zn-URJC-13 catalyst exhibits efficient performance in CO2 cycloaddition reactions and can be reused multiple times.
Article
Chemistry, Applied
Dan Zhao, Vita A. Kondratenko, Dmitry E. Doronkin, Shanlei Han, Jan-Dierk Grunwaldt, Uwe Rodemerck, David Linke, Evgenii V. Kondratenko
Summary: This study demonstrates the potential of cheap and commercially available Zr or Ti-based supports and ZnO to serve as active and selective catalysts for propane dehydrogenation (PDH). The catalytically active species formed in situ under PDH conditions consist of isolated ZnOx. ZnOx on the surface of LaZrOx shows the highest rate of propene formation.
Article
Chemistry, Applied
Hanbyeol Kim, Jung Rae Kim, Young-Kwon Park, Jeong-Myeong Ha, Jungho Jae
Summary: In this study, metal phosphates were used as catalysts for biomass conversion to produce sustainable aromatics through DielsAlder cycloaddition reactions. The effects of synthesis method, activation method, and P/Ti molar ratio on the structure and acid properties of titanium phosphate catalysts were systematically studied. The mesoporous titanium phosphate catalyst synthesized by hydrothermal method at 180℃ for 12 h followed by ethanol refluxing at 60℃ for 24 h at a molar P/Ti ratio of 1 showed the highest surface area and acid site density.
Article
Chemistry, Applied
Yasin Khani, Sumin Pyo, Kwang-Eun Jeong, Chul-Ung Kim, Moonis Ali Khan, Byong-Hun Jeon, Kun-Yi Andrew Lin, Siyoung Q. Choi, Young-Kwon Park
Summary: A protonated form of Zeolite Socony Mobil-5 (H-ZSM-5) catalyst was synthesized through a hydrothermal method using different sources of silica. The effect of loading the catalyst with yttrium, samarium, and gadolinium on the acidic properties was investigated. Among the metal-loaded catalysts, the Sm/LHZ catalyst showed the best performance in the methanol to propylene conversion due to its high amount of weak and intermediate acid sites, while the Gd-LHZ catalyst increased the selectivity towards ethane and propane.
Article
Chemistry, Applied
Michael Franc, Ivana Cisarova, Jan Vesely
Summary: The present study investigates an enantioselective cyclization of enals with imidazolone derivatives catalyzed by a combination of achiral Pd(0) complex and chiral secondary amine. Corresponding spirocyclic imidazolones were produced in high yields with moderate diastereoselectivity and excellent enantioselectivity. The developed co-operative catalytic methodology provides a highly substituted spirocyclic scaffold with four stereogenic centers under mild conditions.
Article
Chemistry, Applied
Mauro Alvarez, Jennifer Cueto, David P. Serrano, Pablo Marin, Salvador Ordonez
Summary: This study focuses on improving the formulation and preparation methods of catalysts for the production of dimethyl carbonate. By using suitable catalyst preparation methods and copper salt precursors, the researchers successfully produced catalysts with optimal performance for dimethyl carbonate formation.
Article
Chemistry, Applied
Claudia J. Keijzer, Luc C. J. Smulders, Dennie Wezendonk, Jan Willem de Rijk, Petra E. de Jongh
Summary: This study investigates the catalytic behavior of alpha-alumina supported silver catalysts in the presence of chloride. It is found that the particle size of silver can affect the selectivity of the catalyst, but different strategies lead to different results. In this size range, the selectivity of ethylene oxide is correlated to the Ag : Al2O3 surface ratio.
Article
Chemistry, Applied
Takeshi Aihara, Wataru Aoki, Michikazu Hara, Keigo Kamata
Summary: The development of acid-base bifunctional catalysts is important for promoting specific chemical transformations. In this study, Ti-based perovskite oxides were synthesized and used as catalysts for two C-C bond-forming reactions (cyanosilylation and Knoevenagel condensation). The highly pure SrTiO3 nanoparticles with a high specific surface area exhibited the highest catalytic performance, and could be easily recovered and reused.
Article
Chemistry, Applied
Olga Gorlova, Petra Pribylova, Eliska Vyskocilova, Katerina Peroutkova, Jan Kohout, Iva Paterova
Summary: This study investigates the Baeyer-Villiger oxidation of beta-cyclocitral using tin-modified mixed oxides as catalysts. The optimal reaction conditions and the effects of various factors on the reaction course and selectivity were determined. The results show that tin-modified mixed oxides exhibit high activity and selectivity in the oxidation reaction.
Article
Chemistry, Applied
M. I. Avila, M. M. Alonso-Doncel, L. Briones, G. Gomez-Pozuelo, J. M. Escola, D. P. Serrano, A. Peral, J. A. Botas
Summary: The catalytic fast pyrolysis of lignin using ion-exchanged zeolite catalysts showed significant improvements in bio-oil quality and the production of aromatic hydrocarbons and oxygenated compounds.
Article
Chemistry, Applied
Enrico Catizzone, Giorgia Ferrarelli, Paolo Bruno, Girolamo Giordano, Massimo Migliori
Summary: The acid-catalysed alcohol conversion reaction is a promising route for de-fossilization strategies. Research on pure alcohol conversion and simultaneous dehydration of mixed alcohols have shown different product compositions, with the type and distribution of acid sites affecting the reaction mechanism.
Article
Chemistry, Applied
Alireza Ranjbari, Juho Kim, Jihee Yu, Jiyun Kim, Mireu Park, Nayoung Kim, Kristof Demeestere, Philippe M. Heynderickx
Summary: This study investigated a novel kinetic model for the adsorption and photocatalytic degradation of methyl orange using commercial ZnO and reduced ZnO photocatalysts. The results provided new insights into the interaction of catalysts with molecules of different charges and compared with a previous study on methylene blue. The presence of oxygen vacancies in ZnO and their effects on adsorption and photocatalytic degradation were analyzed, and the photocatalytic degradation rate of reduced ZnO was found to increase significantly.