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Liquid organic hydrogen carriers (LOHCs) are recognized as excellent long-distance and large-scale hydrogen storage and transportation mediums due to their high hydrogen storage capacity,environmental friendliness,safety,and efficiency.The methylcyclohexane-toluene (MCH-TOL) hydrogen storage system has become an important research direction in the field of hydrogen energy due to its reversibility,high hydrogen storage density (6.16%),and relatively low toxicity.However,the lack of efficient dehydrogenation catalysts poses a bottleneck for industrial application,especially for non-precious metal catalysts,which face challenges such as high reaction temperatures,low selectivity,and poor stability.Designing stable,efficient,and cost-effective dehydrogenation catalysts is crucial to address this issue.This review summarizes the advantages of organic liquid hydrogen storage technology and the current research status of MCH dehydrogenation catalysts.It discusses the design strategies for precious metal Pt-based and non-precious metal Ni-based catalysts from five aspects:metal alloying,addition of promoters,optimization of catalyst supports,addition of surface promoters,and the synergistic effects of new technologies like microwave and electric fields on catalysts.In the future,mixed oxides loaded with multiple active centers as catalysts,particularly Ni-based catalysts with multi-metal synergistic effects to replace Pt-based catalysts,combined with auxiliary methods like microwaves and electric fields,will be the focus of dehydrogenation catalyst research.
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Polydopamine is a novel carrier of noble metal catalyst,which has functional groups such as catechol group,amino group and imine group.It can directly reduce noble metal ions to noble metal nanoparticles without reducing agent.In this paper,the preparation method,polymerization mechanism and morphology control strategy of polydopamine are summarized.Resent progress of polydopamine supported noble metal catalyst is introduced from aspects of catalyst preparation and application.The catalytic mechanism of polydopamine supported noble metal catalysts is analyzed,and their future developments and potential applications are prospected.
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This review summarizes the catalytic properties and the challenges associated with carbon accumulation in four reforming reactions:dry reforming of methane (DRM),steam reforming of methane (SRM),partial oxidation of methane (POM),and autothermal reforming of methane (ATR).It emphasizes the research advancements aimed at mitigating catalyst deactivation and carbon accumulation.Catalyst performance varies among the different reforming reactions,influenced by specific reaction conditions and catalyst composition.The existing solutions are classified into three strategies:(1) utilizing alkaline carrier materials or bimetallic catalysts to minimize carbon deposition and enhance catalyst stability;(2) employing noble metal catalysts to improve stability and carbon resistance,while optimizing non-precious metal catalysts through precise control of reaction conditions and formulations;and (3) designing multi-phase catalyst systems or catalysts with anti-sintering properties to extend catalyst lifespan and enhance reaction efficiency
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Selective hydrogenation of acetylene is a key technology for removing trace acetylene impurities in the refining process of ethylene.The core challenge lies in developing a catalyst system that combines high activity,high ethylene selectivity,and long-term stability.This paper systematically reviews the research progress of palladium-based,gold-based,nickel-based,and copper-based catalysts in recent years,focusing on the effects of nanosizing of active components,bimetallic synergistic effects,carrier interface regulation,novel preparation methods,and additive modification on catalyst performance.Further,it summarizes the deactivation mechanisms of catalysts and anti-carbon deposition strategies,and proposes that future hydrogenation catalysts should focus on the development trends of enhanced low-temperature activity,high dispersion of active components,and long-term stability,providing theoretical guidance for the large-scale preparation of efficient,stable,and low-cost industrial catalysts.
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The treatment of textile dyeing wastewater is an urgent issue due to its significant impact on aquatic ecosystems and human health.Among various treatment technologies,the adsorption technology stands out due to its simplicity,effectiveness,and economic feasibility.The regeneration of adsorbents is a key factor limiting the application of this technology.This paper summarized regeneration technologies for adsorbents and discussed their advantages and disadvantages.It focused on the regeneration treatment characteristics of different materials used in textile dyeing wastewater treatment.It also discussed the current research status of the regeneration process.Researching the regeneration of low-cost adsorbents,establishing practical models,and exploring their industrial applications are important in the field of printing and dyeing wastewater treatment.
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The bi-functional hydrogenation catalysts NiZn/Beta-Al2O3 with different Zn loading contents were prepared by co-impregnation method.The catalysts were characterized by XRD,TEM,N2 adsorption-desorption,NH3-TPD,Py-FTIR and XPS methods and tested in hydro-cycloisomerization of tetralin using a fixed bed microreactor.The results showed that the addition of Zn could inhibit the agglomeration of active metal Ni and thus increased the dispersion of Ni.Meanwhile,the introduction of Zn reduced the strong acid site and B acid site of the catalyst,reduced the ring-opening cracking of tetrahydronaphthalene,and improved the selectivity of cycloisomerization products.As the amount of Zn was 2%(mass fraction),the yield of isomerization products increased from 16% to 24%,and the selectivity of cracking products decreased from 46% to 21%.
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This study aims to prepare Ag/Cu-modified hydroxyapatite (HAP) catalysts for the purification of volatile organic compounds (VOCs).Cu-doped HAP composite carriers were synthesized using the solgel method and the modulation of Ag species and active oxygen by Cu modification was discussed systematically.Catalytic oxidation experiments of toluene demonstrated that the Cu doping level significantly influenced the activity of the Ag/Cu-modified HAP catalyst.Specifically,the Ag/5%Cu-modified HAP catalyst exhibited superior performance,achieving complete toluene oxidation at 255 ℃,which represents a 70 ℃ decline in complete toluene conversion temperature compared to the undoped Ag/HAP catalyst.Characterization results revealed that 5%Cu doping facilitates the formation of an optimal synergistic effect at the Ag-Cu interface.This enhanced synergy between Ag and Cu boosts the generation and migration of reactive oxygen species,thereby significantly improving the low-temperature redox performance of the catalyst and enhancing its catalytic oxidation efficiency for toluene.These findings provide critical theoretical insights and experimental validation for the rational design of high-performance Ag/Cu-based catalytic systems.
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The Hβ zeolites were modified through alkali treatment using NaOH solutions of various conc-entrations and characterized by X-ray diffraction(XRD),nitrogen adsorption-desorption,inductively coupled plasma(ICP) spectroscopy,and ammonia temperature-programmed desorption(NH3-TPD).These materials were subsequently employed to investigate the hydrocracking behavior of tetralin,a representative compound derived from ethylene tar hydrorefining.Compared with untreated Hβ powder,the alkali-treated zeolites exhibited superior hydrocracking performance.This improvement can be attributed to a significant increase in mesoporous volume following alkali treatment,which enhances the diffusion and adsorption of macromolecules within the zeolite framework.Additionally,alkali treatment effectively reduces the acidity of the zeolite,thereby inhibiting side reactions such as alkylation and hydrogen transfer,and promoting the formation of alkylbenzene compounds.Notably,Hβ zeolite treated with 0.5 mol·L-1 NaOH solution demonstrated exceptional catalytic activity.After 200 h of reaction,the conversion of tetralin exceeded 97.0%,with an alkylbenzene selectivity of 84.8%,indicating robust hydrocracking performance.
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The coal char and methane-carbon dioxide co-conversion reaction characteristics were investigated in a thermogravimetric reactor.The effects of reaction temperature the flow rate ratio of methane to carbon dioxide on the methane, carbon dioxide conversion, hydrogen and carbon monoxide yields were examined.The results show that during the co-conversion process,the methane conversion increases with the rise of reaction temperature,while the coal char carbon conversion increases firstly and then decreases with the rise of temperature.The methane and coal char carbon conversion decrease with the increase of methane concentration.Methane and hydrogen play different roles in carbon gasification.Methane has a hindering effect,while carbon dioxide has a promoting effect.Within the range studied,the conversion reaction conditions can be used to adjust the H2/CO ratio in the product gas and better meet the requirements of subsequent process.
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Pyrite (FeS2) is an inexpensive and widely available natural iron sulfide mineral that shows great potential for organic pollutant degradation.However,its easily oxidizable nature leads to the formation of oxidized pyrite whose catalytic activity is to be explored deeply.In this study,we explored the perf-ormance of pyrite in the catalytic degradation of Rhodamine B (RhB) in water in a heterogeneous Fenton system.The effects of catalyst dosage,H2O2 concentration,pH value,anion and humic acid on the degradation of RhB were investigated.The results showed that the degradation of RhB solution was 96.5% in 20 min under the conditions of catalyst dosage of 0.5 g·L-1,H2O2 concentration of 4.0 mmol·L-1 and reaction temperature of 25 ℃.It was adaptable in a wide pH value of 3~9 and effectively resisted the effects of inorganic anions and humic acids in the water column.
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This study discusses the problems and countermeasures of catalysts including geometric appearance,chemical properties and process performance in a thermal power plant running for 24 000 h to give suggestion on catalyst life management.The results show that the microstructure of the gas-turbine SCR catalysts is changed,and pore channels were blocked,which cause a decrease in specific surface area and pore volume.The content of main chemical components is decreased,while impurities and alkali metals causing catalyst slightly poisoning are increased.The process performance test results showed that the denitrification efficiency decreased and ammonia escape increased,while press drop was stable.Catalyst performnace still meets the requirements of running.It is recommended to monitor the performance of the catalyst closely,and if necessary,replacing or regenerating the catalyst to ensure the operation of the unit safely and steadily is important.
