Article
Chemistry, Applied
Christina Wildfire, Victor Abdelsayed, Dushyant Shekhawat, Robert A. Dagle, Stephen D. Davidson, Jianli Hu
Summary: In this study, microwave synthesis of ammonia over Ru/MgO catalysts was conducted at 320℃ under ambient pressure with different Ru loading levels. Higher Ru loading showed better dispersion, leading to decreased sintering and enhanced activity and stability. The microwave reactor also offered faster catalyst recovery compared to traditional thermal convectional Haber Bosch (HB) technology.
Article
Chemistry, Physical
Rahat Javaid, Tetsuya Nanba
Summary: This study aimed to develop a relatively low-cost efficient catalyst for plant scale ammonia synthesis. A mixed oxide of MgO-CeO2 was prepared and used as a support for the Ru catalyst. The Ru/MgO-CeO2 catalyst showed equivalent ammonia synthesis activity compared to Ru/CeO2, making it a cost-effective alternative.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Engineering, Chemical
Kiyoshi Yamazaki, Mitsuru Matsumoto, Hidehito Kubo, Tadahiro Fujitani, Marie Ishikawa, Akinori Sato
Summary: This paper introduces an activity/durability evaluation technique for estimating the catalyst activity after several thousand hours, and conducts an accelerated deterioration durability evaluation of a Ru/MgO catalyst. The study finds that the NH3 conversion decreases almost linearly with the endurance time and explores the relationship between the deterioration rate and endurance temperature using the Arrhenius equation.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Multidisciplinary Sciences
Huihuang Fang, Simson Wu, Tugce Ayvali, Jianwei Zheng, Joshua Fellowes, Ping-Luen Ho, Kwan Chee Leung, Alexander Large, Georg Held, Ryuichi Kato, Kazu Suenaga, Yves Ira A. Reyes, Ho Viet Thang, Hsin-Yi Tiffany Chen, Shik Chi Edman Tsang
Summary: This study finds that atomically dispersed Ru atoms on polar (111) MgO surfaces show the highest rate of ammonia decomposition among all catalysts reported in literature. The strong metal-support interaction and efficient surface coupling reaction contribute to the high activity. The formation of Ru clusters/nanoparticles, however, decreases the catalytic performance.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Idia Msaadi, Ali Rayes, Monica Benito, Noureddine Issaoui, Elies Molins, Brahim Ayed
Summary: Two novel organic-inorganic decavanadate materials with protonated amines were prepared and characterized by X-Ray diffraction, thermogravimetric analysis and IR spectroscopy. The crystal packing of both compounds is governed by non-covalent intermolecular forces, with important contributions from O-H and H-H bonds. The photoluminescence properties and UV-Vis absorption spectra indicate that both compounds exhibit blue and green emissions upon violet light irradiation.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Chemistry, Applied
Rahat Javaid, Tetsuya Nanba
Summary: Efficient 1 wt-% Ru/CeO2/MgO catalysts with different Ce/Mg molar ratios were fabricated in this study. Among them, catalysts with Ce/Mg molar ratios of 0.1 and 0.3 showed the highest ammonia yields at 400 degrees C, even surpassing pure CeO2 supported Ru catalyst. Measurement of activation energies and reaction orders revealed that catalysts with Ce/Mg molar ratios of 0.1 and 0.3 had the lowest activation energies and positive values for the H-2 order. H-2-TPR analysis further demonstrated their higher efficiency for Ru reduction at lower temperatures.
TOPICS IN CATALYSIS
(2023)
Article
Engineering, Environmental
Yanhui Sun, Ming Li, Boyu Pan, Jiaxin Li, Mohammad Hassan Hadizadeh, Fei Xu, Qingzhu Zhang, Wenxing Wang
Summary: This study investigates the transformation mechanisms, kinetics, and potential ecological risks of Ketamine (KET) degradation initiated by •OH/SO4•. The calculated results show that the H15 atom is more likely to be extracted, generating the most active dehydrogenated radical intermediate. The degradation products exhibit decreasing toxicity, but some remain at toxic levels. Additionally, the developmental toxicity, mutagenicity, and carcinogenicity of multiple transformation products increase compared with parent KET. This work contributes to understanding KET mineralization in liquid ecosystems and has implications for prospective industrial applications.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Thiago Galeote Tabuti, Lorena Portela Brazuna, Rafael Gagliardi Antoneli, Eduardo do Valle Ricardo, Rebeca Bacani, Dayane Batista Tada, Eduardo Rezende Triboni
Summary: MgO nanoribbons were synthesized without the use of polymers or organic ligands as structuring agents, making it advantageous compared to commonly used methods. These nanoribbons have the ability to form spherical MgO nanoparticles when subjected to sonication, suggesting their potential use in drug or molecule encapsulation.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Physical
Pavel O. O. Maksimchuk, Kateryna O. O. Hubenko, Martin Knupfer, Vladyslav V. V. Seminko, Vladimir K. K. Klochkov, Oleksandr V. V. Tomchuk, Nataliya S. S. Kavok, Oleksandr V. V. Sorokin, Lesya D. D. Demchenko, Svetlana L. L. Yefimova
Summary: In this study, GdVO4:Eu3+ nanoparticles were investigated as prospective preventive nanozymes. The synthesized nanoparticles were characterized using various techniques. It was found that the nanoparticles exhibited individual crystalline spheroid structures in water solutions. Optical spectroscopy analysis revealed the presence of Fenton- and CAT-like reactions in these solutions. Furthermore, the nanoparticles were shown to protect rat hepatocytes from H2O2-induced oxidative stress.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Analytical
Xinglong Xiong, Baozhong Ma, Ding Zhao, Konghai Xia, Shuyang Shi, Chengyan Wang, Yongqiang Chen
Summary: This study systematically investigated the thermodynamics and phase evolution of calcium nitrate tetrahydrate. The pyrolysis process of calcium nitrate tetrahydrate can be divided into four stages. The activation energies of calcium nitrate pyrolysis were determined using three iso-conversion methods. The pyrolysis process of calcium nitrate further expands the industrial application of nitric acid pressure leaching.
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
(2023)
Article
Biochemistry & Molecular Biology
Ana Amic, Denisa Mastil'ak Cagardova
Summary: This study theoretically examined the inactivation potency of quercetin and flavonoid catecholic metabolites 1-5 on HOO center dot, CH3OO center dot, and O-2(center dot-) under physiological conditions. The results showed that the catecholic moiety of quercetin and metabolites 1-5 played a crucial role in scavenging HOO center dot and CH3OO center dot. Metabolites 1 and 5 were identified as the most potent scavengers of HOO center dot and CH3OO center dot, respectively. Quercetin exhibited higher potency in inactivating HOO center dot and CH3OO center dot via single electron transfer. The SET reaction from the 3-O-phenoxide anion of quercetin represented the most contributing reaction path. Furthermore, all polyphenolic compounds studied showed potency in inactivating O-2(center dot-) through a concerted two-proton-coupled electron transfer mechanism. These findings suggest that metabolites with high radical scavenging potency and enhanced bioavailability may contribute to the health-promoting effects attributed to parent molecules.
Article
Chemistry, Physical
Huaiwei Zhang, Yifan Chen, Liang Bao, Jing-yuan Ge
Summary: A Z-scheme heterojunction with all-solid-state structures was constructed, in which carbon dots acted as electron transferring mediators. The modified photocatalysts showed significantly higher activities, with ammonia production rates reaching above 232 lmol center dot gcal-1 center dot h-1 under light irradiation. The improved catalytic properties were attributed to the increased number of photoinduced oxygen vacancies, excellent visible-light adsorption abilities, and efficient photogenerated electron-hole separation efficiencies for the carbon dots bridged heterostructures. This study provides reasonable guidance for applications in photocatalytic ammonia synthesis and a promising construction strategy for efficient Z-scheme photocatalysts.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Kwan Chee Leung, Sungil Hong, Guangchao Li, Youdong Xing, Bryan Kit Yue Ng, Ping-Luen Ho, Dongpei Ye, Pu Zhao, Ephraem Tan, Olga Safonova, Tai-Sing Wu, Molly Meng-Jung Li, Giannis Mpourmpakis, Shik Chi Edman Tsang
Summary: Catalytic NH3 synthesis and decomposition provide a promising way to store and transport renewable energy. A study found that Ru species confined in a 13X zeolite exhibited the highest catalytic activity for NH3 decomposition, with a lower activation barrier compared to other catalytic materials. The study revealed the unique behavior of cooperative frustrated Lewis pairs created by metal species on the zeolite surface, resulting in dynamic hydrogen shuttling and regeneration of framework Bronsted acid sites.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Materials Science, Ceramics
Takao Sada, Kosuke Tsuji, Arnaud Ndayishimiye, Zhongming Fan, Yoshihiro Fujioka, Clive A. Randall
Summary: Cold sintering process (CSP) can be used for the fabrication of high permittivity dielectric nanocomposite materials, and the Ba(OH)2·8H2O hydrated flux enables densification of BaTiO3 at remarkably low temperatures, resulting in high relative density and permittivity.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Chemistry, Physical
Shunnian Wu, Boon Teoh Tan, Hasanthi L. Senevirathna, Ping Wu
Summary: This study investigates the CO2 adsorption process on MgO and Mg(OH)2 surfaces, revealing that H2O molecules significantly enhance CO2 capture on MgO but not on Mg(OH)2, while dehydration defects on Mg(OH)2 dramatically increase the CO2 absorption energy. Three electronic mechanisms responsible for the increase in CO2 adsorption energy were identified, potentially enabling the design of composite MgO/Mg(OH)2 adsorbents with exciting possibilities in carbon capture, utilisation, and storage applications.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Xilun Zhang, Lin Liu, Ji Feng, Xiaohua Ju, Jiemin Wang, Teng He, Ping Chen
Summary: The use of Pr2O3 support with high density of basic sites and abundant oxygen vacancies, along with strong metal-support interaction, effectively enhances the activity of Ru nanoparticles for ammonia decomposition, resulting in superior catalytic performance of Ru/Pr2O3.
Article
Chemistry, Physical
Xilun Zhang, Lin Liu, Anan Wu, Junfa Zhu, Rui Si, Jianping Guo, Ruting Chen, Qike Jiang, Xiaohua Ju, Ji Feng, Zhitao Xiong, Teng He, Ping Chen
Summary: The synergy between subnano Ru clusters and surface hydride species enhances the activity of the catalyst for ammonia synthesis, resulting in high ammonia yields. Surface hydride species work in synergy with Ru clusters to reduce the energy barrier for nitrogen dissociation and participate in the formation of ammonia.
Article
Chemistry, Physical
Min Dai, Joshua Adedeji Bolarin, Gangtie Lei, Zhi Li, Teng He, Hujun Cao, Ping Chen
Summary: The addition of black TiO2-x reduced by KH, known as K-TiO2-x, significantly enhances the hydrogen storage performance of MgH2 by improving absorption/desorption behaviors and lowering the required temperature. The K2Ti2O3 pseudo-complex of Ti2+, liberated during the sorption process of MgH2, is believed to act as a catalyst by providing nucleation sites, oxygen vacancies, and hydrogen diffusion channels for enhanced hydrogen sorption performance in the catalyzed MgH2 composite.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Xiaohua Ju, Ji Feng, Jiemin Wang, Jianping Guo, Lin Liu
Summary: In this study, cesium decorated Ru/MgO catalysts were synthesized using a one-step solid state method. The Cs-Ru/MgO catalysts exhibited higher activity in ammonia synthesis compared to undecorated Ru/MgO catalysts, even surpassing previous Cs promoted Ru/MgO catalysts. The Cs-Ru/MgO catalysts also demonstrated high stability in ammonia synthesis. The Cs species not only induced the formation of highly dispersed Ru nanoparticles but also modulated the electronic structure of Ru nanoparticles, promoting the dissociation of nitrogen and enhancing the intrinsic activity of the catalyst.
Article
Chemistry, Multidisciplinary
Ji Feng, Lin Liu, Xiaohua Ju, Miaomiao Wang, Xilun Zhang, Jiemin Wang, Ping Chen
Summary: This study successfully synthesized Ru clusters/CeO2 catalyst and found that it exhibited higher activity and stability in ammonia synthesis compared to other catalysts. Kinetic analysis revealed the important role of Ru cluster species in the ammonia synthesis process. This research provides new insights for the design of efficient Ru cluster catalysts.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Chemistry, Physical
Xilun Zhang, Lin Liu, Jiemin Wang, Xiaohua Ju, Rui Si, Ji Feng, Jianping Guo, Ping Chen
Summary: Efficient catalysts are needed to exploit ammonia as a carrier for sustainable energy. This study focuses on oxide supported Ru catalysts, which have shown superior catalytic performances in ammonia synthesis under mild conditions. The synthesis of sub-nanometer Ru clusters on La2O3 catalysts (Ru clusters/La2O3) results in enhanced catalytic performance in ammonia synthesis due to the presence of active La-H species on the catalyst surface. Mechanistic studies reveal the involvement of La-H species in the activation and dissociation of nitrogen molecules, as well as in the synthesis of ammonia.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Ji Feng, Lin Liu, Xilun Zhang, Jiemin Wang, Xiaohua Ju, Ruili Li, Jianping Guo, Teng He, Ping Chen
Summary: Enhancing the interaction between metal nanoparticles and their support can effectively improve the catalytic performance of supported metal catalysts. In this study, enhanced activity was achieved in Y2O3-supported Ru nanoparticles catalysts compared to the analogues with Ru nanoparticles prepared by a different method. The experimental results suggest that the enhanced metal-support interaction facilitates the activation of reactants and leads to excellent catalytic activity in the ammonia synthesis reaction.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Xiaohua Ju, Lin Liu, Tong Zhang, Teng He, Yunhua Xu, Ping Chen
Summary: The catalytic performance of Ru nanoparticles on oxide supports can be greatly enhanced by regulating the surface properties of the supports. In this study, the activity of Ru nanoparticles on gamma-Al2O3 was improved by generating superbasic sites through K doping. The optimized Ru/K-Al2O3 catalyst exhibited a hydrogen production rate of 25.2 mmol g(cat)(-1) min(-1) at 450 degrees C and showed excellent stability for over 120 hours. The presence of superbasic sites promoted the interaction between Ru nanoparticles and K-Al2O3 support, and the surface superbasic sites played a key role in modulating the electronic properties of Ru nanoparticles, leading to enhanced intrinsic activity. The use of K-Al2O3 superbase could expand the application of solid superbase materials for Ru-based ammonia decomposition catalysts.
Article
Chemistry, Physical
Tong Zhang, Xiaohua Ju, Lvye Liu, Lin Liu, Teng He, Yunhua Xu, Hanying Wang, Ping Chen
Summary: Ru/ZrO2 catalysts were prepared by milling and precipitation methods and applied in ammonia decomposition reaction. It was found that the catalyst obtained from precipitation method exhibited higher activity and stability compared to the one obtained from milling method. The superior performance of the catalyst from precipitation method was attributed to the modulated electronic structure of Ru nanoparticles and the intimate interaction between Ru nanoparticles and the ZrO2 support.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Ji Feng, Lin Liu, Xiaohua Ju, Qike Jiang, Jiemin Wang, Jianping Guo, Teng He, Ping Chen
Summary: Utilization of promoters to improve the catalytic performance of supported metal catalysts is a promising strategy. In this study, an efficient Ru-based ammonia synthesis catalyst (Ce-Ru/Al2O3) was developed by decorating Ru nanoparticles on γ-alumina with sub-nanometer ceria (CeO2) species. Ce-Ru/Al2O3 showed a 10-fold enhanced activity compared to neat Ru/Al2O3 at 400°C and 1.0 MPa. The enhanced activity was attributed to the function of sub-nanometer CeO2 species that led to electron transfer and weakened hydrogen poisoning effect, facilitating nitrogen adsorption and hydrogenation. This work highlights the important role of highly dispersed rare earth oxide promoter species in modulating the structure and catalytic performance of supported Ru NPs for ammonia synthesis.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
