Article
Chemistry, Multidisciplinary
Yun-Fei Shi, Pei-Lin Kang, Cheng Shang, Zhi-Pan Liu
Summary: In this study, large-scale machine learning atomic simulation combined with microkinetics-guided machine learning pathway search was used to explore the reaction pathways for CO2 and CO hydrogenation on Cu/ZnO/Al2O3 catalysts for methanol synthesis. The research findings indicate that CO2 hydrogenation occurs exclusively at the step-edge of the (211) surface, while CO hydrogenation has limited effect on the reaction kinetics. Moreover, it was observed that Zn decorates at the step-edge of the Cu(211) surface, but higher coverages of Zn poison the catalyst.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Niels D. Nielsen, Anker D. Jensen, Jakob M. Christensen
Summary: Experiments showed that CO2 is more favorable for methanol synthesis on Cu catalyst compared to CO. At low conversion conditions, CO has inhibiting effects, but as conversion is increased, a beneficial role of CO is observed. CO's beneficial role mainly comes from its promotion of the water-gas shift reaction, which helps to reduce the inhibitory effect of water on Cu-based catalysts.
JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Physical
Diptendu Roy, Shyama Charan Mandal, Biswarup Pathak
Summary: By utilizing machine learning, this study investigates the application of high entropy alloy catalysts in CO2 hydrogenation to methanol. Through stability and catalytic activity studies, it is found that adsorption energy values of CO2 reduction intermediates on CuCoNiZnMg and CuCoNiZnSn-based catalysts can effectively predict the activity and selectivity of CO2 hydrogenation to methanol.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Wei Xiong, Zongfang Wu, Xuanye Chen, Jieqiong Ding, Aiai Ye, Wenhua Zhang, Weixin Huang
Summary: Through experimental and theoretical calculation studies, we find that the Cu{110} facet is the most active facet for ZnO-Cu interfacial catalysis in CO2 hydrogenation to methanol, and the Cu{100} facet is the most active facet for both ZnO-Cu interfacial catalysis and Cu catalysis in the RWGS reaction. Although the ZnO-Cu interface has higher catalytic activity, the RWGS reaction mainly occurs on the bare Cu surface.
SCIENCE CHINA-CHEMISTRY
(2023)
Article
Multidisciplinary Sciences
Yuchao Chai, Bin Qin, Bonan Li, Weili Dai, Guangjun Wu, Naijia Guan, Landong Li
Summary: This study reports a method for selectively hydrogenating carbon dioxide to methanol using renewable hydrogen sources, which is both environmentally friendly and carbon neutral. By designing faujasite-encaged mononuclear Cu centers, stable methanol production and selectivity were achieved. This work provides a clear example of structure-activity relationship in catalysis and highlights the advantages of zeolite catalysis in complex chemical transformations.
NATIONAL SCIENCE REVIEW
(2023)
Article
Chemistry, Physical
Chaoyang Zhang, Ying Zhang, Hailian Xiao, Jiancheng Zhang, Long Li, Lina Wang, Qiang Bai, Manhong Liu, Zhaobo Wang, Ning Sui
Summary: The PtCu electrocatalyst supported on graphdiyne nanocomposite displayed superior electrocatalytic activity towards methanol oxidation reaction, with a high mass activity of 336 mA mg(-1). Additionally, the presence of graphdiyne significantly improved the CO tolerance property of PtCu, making the electrocatalyst a promising candidate for commercialization in direct methanol fuel cells.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2021)
Article
Chemistry, Applied
Huichang Liang, Guohai Zhang, Zhiyu Li, Yuchun Zhang, Peng Fu
Summary: This work first examines the active sites of copper-based catalysts and their impacts on activity and selectivity, followed by an overview of the regulation of the active sites and pathways for CO2 hydrogenation reactions. Strategies such as additive control, carrier effect, and morphological modification can alter the type and distribution of active sites. The main intermediates for methanol synthesis by CO2 hydrogenation are carboxyl species and formate species. The formate pathway can be further divided into two pathways: the HCOO* pathway and the r-HCOO* pathway, depending on the intermediate involved. The rate-determining step for methanol synthesis by CO2 hydrogenation in the formate pathway is the hydrogenation of formate, while the rate-limiting steps for the carboxyl species pathway are the formation of CO/HCO species and the dissociation of COHOH* species.
FUEL PROCESSING TECHNOLOGY
(2023)
Article
Chemistry, Applied
Wanli Zhang, Yao Yao, Shaoqu Xie, Kristian Gubsch, Yanhui Yang, Xingying Lan, Hongfei Lin
Summary: Converting formate to methanol as an economic strategy involves understanding the interaction between metal catalyst and support, with ZrO2 found to promote Cu catalysts' activity and selectivity in formate ester hydrogenation. By optimizing catalyst properties and reaction conditions, a significant yield of methanol can be achieved, with the Cu/ZrO2 catalyst exhibiting promising results in ester hydrogenation reactions. The choice of calcination temperature in catalyst synthesis plays a crucial role in determining Cu valence states, ZrO2 support structure, and interactions between Cu and ZrO2, which can be elucidated through various characterization tools like XRD, XPS, and HRTEM.
Article
Chemistry, Multidisciplinary
Thaylan Pinheiro Araujo, Adrian H. Hergesell, Dario Faust-Akl, Simon Buchele, Joseph A. Stewart, Cecilia Mondelli, Javier Perez-Ramirez
Summary: This study found that copper-based systems are more active in CO hydrogenation and suitable for methanol production using CO; ZnO-ZrO2 exhibits strong resistance to deactivation in CO2-rich streams, showing good reversibility; the research emphasizes the importance of catalyst and process design in advancing CO2 utilization technologies.
Article
Chemistry, Physical
Georg Kastlunger, Lei Wang, Nitish Govindarajan, Hendrik H. Heenen, Stefan Ringe, Thomas Jaramillo, Christopher Hahn, Karen Chan
Summary: Electrochemical conversion of CO(2) into hydrocarbons and oxygenates is a promising approach to closing the carbon cycle in modern technology. However, the reaction mechanisms for different products are disputed, making it difficult to find suitable catalyst materials. In this study, the rate-limiting steps in CO reduction on Cu were conclusively identified through experiments and theoretical analysis. The findings provide insights for future mechanistic studies and catalyst design.
Article
Chemistry, Physical
A. B. Dongil, J. M. Conesa, L. Pastor-Perez, A. Sepulveda-Escribano, A. Guerrero-Ruiz, I. Rodriguez-Ramos
Summary: The carbothermal synthesis of monometallic and bimetallic molybdenum carbide and copper catalysts supported on high surface area graphite was studied for the hydrogenation of CO2 to methanol. The catalysts showed different phases and behaviors at different temperatures, with the bimetallic sample being less affected by the formation of hydride. The presence of copper increased the activity and selectivity of molybdenum carbide, leading to a cooperation reaction between copper and molybdenum phase.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Environmental
Yue Xin, Qi Li, Sanmei Wang, Sunpei Hu, Liangbing Wang
Summary: Cu/Nb2O5 composite aerogel shows potential as a high-performance catalyst for the hydrogenation of CO2 into methanol. Abundant interfaces between Cu and Nb2O5 act as active sites for the adsorption, activation, and selective conversion of CO2. Methanol production occurs through the formate pathway over Cu/Nb2O5. This work provides a new approach for the design of efficient catalysts with rich active sites.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Physical
Nat Phongprueksathat, Kah Wei Ting, Shinya Mine, Yuan Jing, Ryo Toyoshima, Hiroshi Kondoh, Ken-ichi Shimizu, Takashi Toyao, Atsushi Urakawa
Summary: Low temperature and high pressure are advantageous conditions for achieving high conversion and selectivity in CO2 hydrogenation. Re/TiO2 has been identified as a promising catalyst with higher activity than the industrial Cu/ZnO/Al2O3 catalyst at high pressure and low temperature. The study provides insights into the nature of active sites and active species, demonstrating the active role of cationic Re species in CO2 activation and formate intermediate formation.
Article
Chemistry, Multidisciplinary
Frederic C. Meunier, Isaac Dansette, Anaelle Paredes-Nunez, Yves Schuurman
Summary: Cu/ZrO2 is a promising catalyst for CO2 hydrogenation to methanol. Three different types of formates were observed under reaction conditions, with one bound to metallic Cu and the other two bound to ZrO2. The Cu-bound formate, representing only about 7% of surface formates, was found to be highly reactive and the sole source of methanol production. This study highlights the importance of quantitative IR analysis and transient methods in understanding the role of surface species.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Energy & Fuels
Yuhua Zhang, Yumei He, Mingyang Cao, Bing Liu, Jinlin Li
Summary: Mo-Co-C-N catalysts synthesized using ZIF-67 as the precursor are highly efficient catalysts for converting CO2 to methanol. The optimized Mo-Co(2:1)-C-N(800) catalyst achieves the highest methanol STY of 3.3 mmol/gcat/h at a temperature of 275 degrees C (XCO2 = 9.2%, SMeOH = 58.4%). Formation of Mo2C and Co6Mo6C2 during the preparation process catalyzes both the RWGS and methanol synthesis reactions. XPS and Temperature Programed studies indicate that higher calcination temperatures (800 degrees C) result in the formation of more oxygen vacancies, which improves CO2 dissociation adsorption and increases methanol selectivity.
Article
Chemistry, Physical
J. A. Andersen, J. M. Christensen, M. ostberg, A. Bogaerts, A. D. Jensen
Summary: This study investigated the plasma-catalytic ammonia decomposition for producing hydrogen using a packed-bed dielectric barrier discharge reactor. The introduction of dielectric materials with certain dielectric constants improved the ammonia decomposition, with MgAl2O4 showing the highest conversion rate. Further studies are needed to optimize the efficiency of this technology.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Physical
Lauge Sven Thorsen, Malene Stryhn Thestrup Jensen, Mille Stub Pullich, Jakob Munkholt Christensen, Hamid Hashemi, Peter Glarborg
Summary: The oxidation properties of n-heptane were investigated under different pressure, oxygen concentration, and temperature conditions. The experiments showed a negative temperature coefficient (NTC) behavior in the NTC region, which was less pronounced at higher pressure or oxygen concentration. Comparison between observed concentration profiles and predictions from different mechanisms suggested that only the mechanisms from NUI and Polimi captured the NTC behavior. The model from Zhang et al. provided the best overall agreement and was selected for detailed analysis.
INTERNATIONAL JOURNAL OF CHEMICAL KINETICS
(2022)
Article
Engineering, Environmental
J. A. Andersen, M. C. Holm, K. van't Veer, J. M. Christensen, M. Ostberg, A. Bogaerts, A. D. Jensen
Summary: The study investigates the factors affecting ammonia synthesis in a dielectric barrier discharge reactor, using both experiments and a plasma kinetic model. The effects of plasma power, feed flow rate, N2:H2 feed ratio, gas residence time, temperature, and packing material were examined. The results show that increasing the feed flow rate and gas temperature with a packing material present in the plasma can enhance the ammonia synthesis rate.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Energy & Fuels
Lauge Sven Thorsen, Malene Stryhn Thestrup Jensen, Mille Stub Pullich, Jakob Munkholt Christensen, Hamid Hashemi, Peter Glarborg
Summary: This study evaluates the application of diesel as a pilot fuel in natural gas combustion in two-stroke maritime engines, focusing on high-pressure oxidation of methane/n-heptane mixtures. Laminar flow reactor experiments were conducted at different temperatures and pressures. The results showed that n-heptane conversion started at temperatures below 600 K and a negative temperature coefficient region was observed at 21 bar. Methane oxidation initiated after n-heptane was consumed. The presence of methane promoted n-heptane oxidation compared to pure n-heptane and NH3/n-heptane mixtures. The model by Zhang et al. showed good agreement with the experimental data, although the low-temperature conversion of n-heptane at 21 bar and stoichiometric conditions was underpredicted, potentially due to missing chemical coupling between n-heptane and methane in the model.
Article
Chemistry, Applied
Amado Velazquez-Palenzuela, Burak Ulusoy, Kim Dam-Johansen, Jakob Munkholt Christensen
Summary: Photocatalytic coatings are investigated for their ability to remove NOx gases by converting them into nitrate via photo-oxidation. This study focuses on the conversion of nitrite to nitrate in the aqueous phase and its implications for NOx immobilization in humid environments. The performance of TiO2 nanoparticles and corresponding acrylic binder coatings in the conversion of nitrite is studied using colorimetric and spectroscopic methods.
PROGRESS IN ORGANIC COATINGS
(2023)
Article
Engineering, Environmental
Frederik Zafiryadis, Anker Degn Jensen, Weigang Lin, Sonnik Clausen, Elisabeth Akoh Hove, Morten Boberg Larsen, Hao Wu
Summary: The cracking of sugars to glycolaldehyde and other oxygenates shows potential in lab-scale fluidized beds. This study adopts a gas-phase kinetics model and implements it into the Computational Particle Fluid Dynamics (CPFD) framework to simulate sugar cracking in a pilot-scale circulating fluidized bed riser. The results show good agreement with experimental data and suggest the need for more accurate predictions of product yields.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Chemical
J. A. Andersen, K. van't Veer, J. M. Christensen, M. Ostberg, A. Bogaerts, A. D. Jensen
Summary: The use of ammonia as a storage medium for hydrogen and its plasma-catalytic decomposition for retrieval of hydrogen are investigated. Experimental results show that increasing the specific energy input enhances the ammonia conversion. A kinetic model is used to analyze the decomposition mechanism, indicating that the collisions between NH3 and high-energy electrons initiate the decomposition.
CHEMICAL ENGINEERING SCIENCE
(2023)
Review
Engineering, Chemical
Frederik Zafiryadis, Anker Degn Jensen, Weigang Lin, Elisabeth Akoh Hove, Morten Boberg Larsen, Hao Wu
Summary: This paper provides a thorough and up-to-date review of experimental and numerical investigations of gas-liquid sprays into gas-solid fluidized beds. It presents a phenomenological description of the prevalent mechanisms of gas-liquid injection under different operating conditions and identifies suitable computational fluid dynamic models for simulating the mechanisms involved in gas-liquid-solid interactions, along with recommendations for future work.
Review
Chemistry, Physical
Hamed Baniamerian, Martin Hoj, Matthias Josef Beier, Anker Degn Jensen
Summary: This review discusses the attractive approaches of catalytic conversion of (ligno)cellulosic biomass for the production of valuable oxygenated chemicals and platform molecules under hydrothermal or pyrolysis conditions. To design the most effective catalysts and gain a better understanding of the processes, the main reactions and possible products obtained from cellulose catalytic valorization, specifically diols, are discussed. The review systematically summarizes recent advancements of heterogeneous catalysts and their structure-activity relationships for the selective production of diols from cellulose and cellulose-derived sugars under both pyrolysis and hydrothermal conditions.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Thermodynamics
Lauge S. Thorsen, Malene S. T. Jensen, Mille S. Pullich, Jakob M. Christensen, Hamid Hashemi, Peter Glarborg, Vladimir A. Alekseev, Elna J. K. Nilsson, Ziyu Wang, Bowen Mei, Ning Liu, Yiguang Ju
Summary: Oxidation characteristics of NH3/n-heptane mixtures were experimentally investigated at pressures up to 100 atm and temperatures between 400-900K in laminar flow and jet-stirred reactors. A detailed kinetic model was developed, incorporating updated subsets for hydrogen and amines, and introducing a subset for the NH2 + n-heptane reaction. The kinetic model accurately predicted ignition delay times and high pressure experimental data. It was found that updated rate constants for NH2 + HO2 and NH2 + n-C7H16 are crucial for reliable predictions of ignition and oxidation behaviors at high pressure.
COMBUSTION AND FLAME
(2023)
Review
Engineering, Environmental
William Gundtorp, Thomas Klint Torp, Anker Degn Jensen
Summary: Due to convenience and toxicity, research on the catalytic oxidation of poly-chlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) is mainly conducted on model compounds instead of PCDD/Fs themselves. This raises questions about the validity of using model compounds to design catalysts for PCDD/F removal. A review of the literature on catalytic destruction of PCDD/Fs and model compounds indicates that their reaction kinetics are similar, but with some deviations in gas phase composition. It is found that V2O5/TiO2-based catalysts are the most studied and achieve higher catalytic activity compared to other non-precious metal catalysts.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Hamed Baniamerian, Martin Hoj, Matthias Josef Beier, Anker Degn Jensen
Summary: Hydrous pyrolysis of glucose is a promising method to produce glycolaldehyde and other valuable oxygenates. A pulsed chromatographic method was proposed to investigate the effect of operating parameters on the product distribution and glycolaldehyde yield. This technique provided insights into the reaction pathways and allowed for determination of the reaction time-frame and rate parameters.
REACTION CHEMISTRY & ENGINEERING
(2023)
Article
Energy & Fuels
Wenhao Hu, Zsuzsa Sarossy, Anker Degn Jensen, Anders Egede Daugaard, Peter Arendt Jensen
Summary: In this study, the pyrolysis of pure low density polyethylene was investigated using a lab-scale two-stage fixed-bed pyrolyzer. Different catalytic materials were used in the second reactor to upgrade the vapors. The results showed that the use of certain catalysts and higher temperatures can significantly decrease the chain length of hydrocarbons in the condensed product and convert the wax into a liquid.
