The Nature of Active Sites for Plasmon-Mediated Photothermal Catalysis and Heat-Coupled Photocatalysis in Dry Reforming of Methane

Solar energy-induced catalysis has been attracting intensive interests and its quantum efficiencies in plasmon-mediated photothermal catalysis(P-photothermal catalysis)and external heat-coupled photocatalysis(E-photothermal catalysis)are ultimately determined by the catalyst structure for photo-induced energetic hot carriers.Herein,different catalysts of supported(TiO_(2)-P25 and Al_(2)O_(3))platinum quantum dots are employed in photo,thermal,and photothermal catalytic dry reforming of methane.Integrated experimental and computational results unveil different active sites(hot zones)on the two catalysts for photo,thermal,and photothermal catalysis.The hot zones of P-photothermal catalysis are identified to be the metal-support interface on Pt/P25 and the Pt surface on Pt/Al_(2)O_(3),respectively.However,a change of the active site to the Pt surface on Pt/P25 is for the first time observed in E-photothermal catalysis(external heating temperature of 700℃).The hot zones contribute to the significant enhancements in photothermal catalytic reactivity against thermocatalysis.This study helps to understand the reaction mechanism of photothermal catalysis to exploit efficient catalysts for solar energy utilization and fossil fuels upgrading.

Machine learning-driven optimization of plasma-catalytic dry reforming of methane

This study investigates the dry reformation of methane(DRM)over Ni/Al_(2)O_(3)catalysts in a dielectric barrier discharge(DBD)non-thermal plasma reactor.A novel hybrid machine learning(ML)model is developed to optimize the plasma-catalytic DRM reaction with limited experimental data.To address the non-linear and complex nature of the plasma-catalytic DRM process,the hybrid ML model integrates three well-established algorithms:regression trees,support vector regression,and artificial neural networks.A genetic algorithm(GA)is then used to optimize the hyperparameters of each algorithm within the hybrid ML model.The ML model achieved excellent agreement with the experimental data,demonstrating its efficacy in accurately predicting and optimizing the DRM process.The model was subsequently used to investigate the impact of various operating parameters on the plasma-catalytic DRM performance.We found that the optimal discharge power(20 W),CO_(2)/CH_(4)molar ratio(1.5),and Ni loading(7.8 wt%)resulted in the maximum energy yield at a total flow rate of∼51 mL/min.Furthermore,we investigated the relative significance of each operating parameter on the performance of the plasma-catalytic DRM process.The results show that the total flow rate had the greatest influence on the conversion,with a significance exceeding 35%for each output,while the Ni loading had the least impact on the overall reaction performance.This hybrid model demonstrates a remarkable ability to extract valuable insights from limited datasets,enabling the development and optimization of more efficient and selective plasma-catalytic chemical processes.

Regulating crystal phase of TiO_(2) to enhance catalytic activity of Ni/TiO_(2) for solar-driven dry reforming of methane

Ni/TiO_(2) catalyst is widely employed for photo-driven DRM reaction while the influence of crystal structure of TiO_(2) remains unclear.In this work,the rutile/anatase ratio in supports was successfully controlled by varying the calcination temperature of anatase-TiO_(2).Structural characterizations revealed that a distinct TiO_(x) coating on the Ni nanoparticles(NPs)was evident for Ni/TiO_(2)-700 catalyst due to strong metal-support interaction.It is observed that the TiOx overlayer gradually disappeared as the ratio of rutile/anatase increased,thereby enhancing the exposure of Ni active sites.The exposed Ni sites enhanced visible light absorption and boosted the dissociation capability of CH4,which led to the much elevated catalytic activity for Ni/TiO_(2)-950 in which rutile dominated.Therefore,the catalytic activity of solar-driven DRM reaction was significantly influenced by the rutile/anatase ratio.Ni/TiO_(2)-950,characterized by a predominant rutile phase,exhibited the highest DRM reactivity,with remarkable H_(2) and CO production rates reaching as high as 87.4 and 220.2 mmol/(g·h),respectively.These rates were approximately 257 and 130 times higher,respectively,compared to those obtained on Ni/TiO_(2)-700 with anatase.This study suggests that the optimization of crystal structure of TiO_(2) support can effectively enhance the performance of photothermal DRM reaction.

Controllable synthesis of CuAlO_(2) via solid-phase method and its catalytic performance for methanol steam reforming to hydrogen

This study explores the controllable synthesis of CuAlO_(2) using copper hydroxide and pseudo-boehmite powders as raw materials via a simple solid-phase ball milling method,along with its catalytic performance investigation in methanol steam reforming(MSR).Various catalysts were prepared under different conditions,such as calcination temperature,calcination atmosphere,and heating rate.Characterization techniques including BET,XRD,XPS,SEM and H2-TPR were employed to analyze the samples.The results revealed significant effects of calcination temperature on the phase compositions,specific surface area,reduction performance,and surface properties of the CA-T catalysts.Based on the findings,a synthesis route of CuAlO_(2) via the solid-phase method was proposed,highlighting the importance of high calcination temperature,nitrogen atmosphere,and low heating rate for CuAlO_(2) formation.Catalytic evaluation data demonstrated that CuAlO_(2) could catalyze MSR without pre-reduction,with the catalytic performance of CA-T catalysts being notably influenced by calcination temperature.Among the prepared catalysts,the CA-1100 catalyst exhibited the highest catalytic activity and stability.The findings of this study might be useful for the further study of the catalytic material for sustained release catalysis,including the synthesis of catalytic materials and the regulation of sustained release catalytic performance.

Charge transfer in plasma assisted dry reforming of methane using a nanosecond pulsed packed-bed reactor discharge

This paper is aimed to investigate the effect of packing material on plasma characteristic from the viewpoint of charge transfer process.Both the charge accumulation and release processes in the dielectric barrier discharge reactor and packed-bed reactor were investigated by measuring voltage and current waveforms and taking ICCD images.The packing material was ZrO2 pellets and the reactors were driven by a parameterized nanosecond pulse source.The quantity of transferred charges in the dielectric barrier discharge reactor was enhanced when decreasing pulse rise time or increasing pulse width(within 150 ns),but reduced when the gas gap was packed with pellets.The quantity of accumulated charges in the primary discharge was larger than the quantity of released charges in the secondary discharges in the dielectric barrier discharge reactor,but they were almost equal in the packed-bed reactor.It indicates that the discharge behavior has been changed from the view of charge transfer process once the gas gap was packed with pellets,and the ICCD images confirmed it.

Research progress on methane conversion coupling photocatalysis and thermocatalysis

Conversion of methane into value-added chemicals is of significance for methane utilization and industrial demand of primary chemical products.The barrier associated with the nonpolar structure of methane and the high bond energy C-H bond(4.57 eV)makes it difficult to realize methane conversion and activation under mild conditions.The photothermal synergetic strategy by combining photon energy and thermo energy provides an advanced philosophy to achieve efficient methane conversion.In this review,we overview the current pioneering studies of photothermal methane indirect conversion and present the methane direct conversion by the way of photocatalysis and thermocatalysis to provide a fundamental understanding of methane activation.Finally,we end this review with a discussion on the remaining challenges and perspectives of methane direct conversion over single-atom catalysts via photothermal synergetic strategy.

Tuning combined steam and dry reforming of methane for “metgas”production: A thermodynamic approach and state-of-the-art catalysts

Nowadays,combined steam and dry reforming of methane(CSDRM)is viewed as a new alternative for the production of high-quality syngas(termed as"metgas",H2:CO of 2.0)suitable for subsequent synthesis of methanol,considered as a promising renewable energy vector to substitute fossil fuel resources.Adequate operation conditions(molar feed composition,temperature and pressure)are required for the sole production of"metgas"while achieving high CH4,CO2 and H2O conversion levels.In this work,thermodynamic equilibrium analysis of CSDRM has been performed using Gibbs free energy minimization where;(i)the effect of temperature(range:200-1000℃),(ii)feed composition(stoichiometric ratio as compared to a feed under excess steam or excess carbon dioxide),(iii)pressure(range:1-20 bar)and,(iv)the presence of a gaseous diluent on coke yields,reactivity levels and selectivity towards"metgas"were investigated.Running CSDRM at a temperature of at least 800℃,a pressure of 1 bar and under a feed composition where CO2-H2O/CH4 is around 1.0,are optimum conditions for the theoretical production of"metgas"while minimizing C(S)formation for longer experimental catalytic runs.A second part of this work presents a review of the recent progresses in the design of(principally)Ni-based catalysts along with some mechanistic and kinetic modeling aspects for the targeted CSDRM reaction.As compared to noble metals,their high availability,low cost and good intrinsic activity levels are main reasons for increasing research dedications in understanding deactivation potentials and providing amelioration strategies for further development.Deactivation causes and main orientations towards designing deactivationresistant supported Ni nanoparticles are clearly addressed and analyzed.Reported procedures based on salient catalytic features(i.e.,acidity/basicity character,redox properties,oxygen mobility,metal-support interaction)and recently employed innovative tactics(such as confinement within mesoporous systems,stabilization through core shell structures or on carbide surfaces)are highlighted and their impact on Ni0reactivity and stability are discussed.The final aspect of this review encloses the major directions and trends for improving synthesis/preparation designs of Ni-based catalysts for the sake of upgrading their usage into industrially oriented combined reforming operations.

Glycerol steam reforming over hydrothermal synthetic Ni-Ca/attapulgite for green hydrogen generation

Glycerol steam reforming(GSR)is one of the promising technologies that can realize renewable hydrogen production and efficient utilization of crude glycerol.To illuminate the functions of Ca content(3%,6%,9%,and 12%,by mass)and preparation method for Ni/ATP catalyst structure and its catalytic behaviors,the Ni-xCa/ATP(x=3%,6%,9%,and 12%,by mass)catalysts are prepared by co-impregnation(ci)and hydrothermal synthesis(hs)method and then tested in GSR.Characterization results of XRD,N_(2) adsorption–desorption,H_(2)-TPR,HRTEM,XPS,and NH_(3)/CO_(2)-TPD demonstrate that the combined effect between appropriate Ca additive(6%,by mass)and hs enhance catalyst reducibility,uniform distribution of Ca additive and nickel species over ATP,and adsorption for CO_(2).This attributes to hs method protects the ATP framework through suppressing the interaction of Ca with ATP and promotes the formation of NiCaOx interface sites.Therefore,Ni-6Ca/ATP-hs exhibits the highest conversion(86.77%)of glycerol to gas product and H_(2) yield(76.17%)and selectivity(58.56%)during GSR.Furthermore,XRD,HRTEM,TGDTG and Raman analyses confirm that Ni-6Ca/ATP-hs also reveals outstanding anti-sintering and coke resistance.In addition,the structural evolution process of Ni/ATP catalyst with Ca introduction and hs method is presented.Considering the high performance,simple preparation process and low cost,the as-prepared catalyst providing new opportunities for utilization of glycerol derived from biodiesel industry.

Is a catalyst always beneficial in plasma catalysis? Insights from the many physical and chemical interactions

Plasma-catalytic dry reforming of CH_(4)(DRM) is promising to convert the greenhouse gasses CH_(4) and CO_(2) into value-added chemicals, thus simultaneously providing an alternative to fossil resources as feedstock for the chemical industry. However, while many experiments have been dedicated to plasma-catalytic DRM, there is no consensus yet in literature on the optimal choice of catalyst for targeted products,because the underlying mechanisms are far from understood. Indeed, plasma catalysis is very complex,as it encompasses various chemical and physical interactions between plasma and catalyst, which depend on many parameters. This complexity hampers the comparison of experimental results from different studies, which, in our opinion, is an important bottleneck in the further development of this promising research field. Hence, in this perspective paper, we describe the important physical and chemical effects that should be accounted for when designing plasma-catalytic experiments in general, high-lighting the need for standardized experimental setups, as well as careful documentation of packing properties and reaction conditions, to further advance this research field. On the other hand, many parameters also create many windows of opportunity for further optimizing plasma-catalytic systems.Finally, various experiments also reveal the lack of improvement in plasma catalysis compared to plasma-only, specifically for DRM, but the underlying mechanisms are unclear. Therefore, we present our newly developed coupled plasma-surface kinetics model for DRM, to provide more insight in the underlying reasons. Our model illustrates that transition metal catalysts can adversely affect plasmacatalytic DRM, if radicals dominate the plasma-catalyst interactions. Thus, we demonstrate that a good understanding of the plasma-catalyst interactions is crucial to avoiding conditions at which these interactions negatively affect the results, and we provide some recommendations for improvement. For instance, we believe that plasma-catalytic DRM may benefit more from higher reaction temperatures,at which vibrational excitation can enhance the surface reactions.

Advanced characterization for industrial catalysis applications

The interplay between analytical technique and industrial practice has been central in the development of catalytic materials for processing petroleum. This article presents reviews of key aspects of two of the most important classes of catalytic materials: noble-metal Pt nanoparticles (NPs) on alumina, which are the basis of catalytic reforming;and layered sulfides of Mo and W, which catalyze hydrogenation and hetero-atom removal in hydroprocessing. The state of understanding of Pt cluster growth and resulting structures, as developed using X-ray absorption spectroscopy and STEM, is reviewed. Influences of both Pt reduction temperature in hydrogen gas, and oxidizing pretreatment conditions prior to Pt reduction, are considered. Recent work by the present authors on Pt NP structure evolution is presented in the context of the previous work. A review is subsequently presented of layered sulfide based NPs, summarizing contributions from a range of analytical techniques. Work on active site structures of sulfide NPs is reviewed, focusing particularly on the critical interactions of active edge sites with sulfur and hydrogen in chemisorption, physisorption, and spillover interactions. New temperature programmed reduction (TPR) results are presented for supported and unsupported sulfide NPs. Structural changes in TPR of alumina-supported MoS2 are investigated using extended X-ray absorption fine structure and density functional theory modeling, and are determined to arise from removal of identifiable edge-site sulfur species.

Auto-thermal reforming of acetic acid for hydrogen production by Zn_(x)Ni_(y)CrO_(m±δ) catalysts:Effect of Cr promoted Ni-Zn intermetallic compound

A series of Zn_(x)Ni_(y)CrO_(m±δ)catalysts were synthesized via a typical co-precipitation method,in which Zn-Cr layered double hydroxides(LDHs)were found and Ni-Zn intermetallic compound(IMC)was formed after reduction in hydrogen.During auto-thermal reforming(ATR)of acetic acid(HAc),the Ni-Zn IMC was transformed into Ni/(amorphous-ZnO)-ZnCr_(2)O_(4) species with uniformed distribution and appropriate interaction within these Ni-Zn-Cr-O species;besides,the adsorbed oxygen promoted the activation and transfer of oxygen species;therefore,deactivation by oxidation,sintering and coking was inhibited.And the optimized Zn_(2.37)Ni_(0.63)CrO_(4.5±δ)catalyst presented high activity and stability in a 45-h ATR test with HAc conversion near 100%and hydrogen yield at 2.7 mol-H_(2)/mol-HAc,showing potential for hydrogen production via ATR of HAc.

Bring into Full Play the Role of Catalytic Reforming Unit

This article after analyzing the current status of catalytic reforming technology in China puts forward a host of problems related with catalytic reforming capacity, feedstock, size and techno-economic indicators. To solve these problems it is proposed to properly increase the catalytic reforming capacity,extend the feedstock source, and eliminate the bottlenecks to boost the capacity of existing units, improve the operating and management level, as well as speed up R&D work, disseminate new technologies, new processes and novel catalysts.

Molecular catalysis for the steam reforming of ethanol

In this paper, the application of molecular catalysis for steam reforming of ethanol （SRE） is reviewed. Eight metals （Ni, Co, Cu Pt, Rh, Pd, Ir and Ru） have shown high catalytic activity for SRE. Among them Ni and Rh are very promising because of high d character in the metal bond and low metal-oxygen bonding （vs. metal-carbon）. They can effectively promote C-C bond cleavage in the rate-determining process during SRE. However, Rh is weak in water-gas-shift so that CH4 and CO become the main by-products at low reaction temperatures, while Ni catalysts suffer from rapid deactivation due to coking and sintering. Two low-temperature CO-free catalysts have been developed in our lab, namely Rh-Fe/Ca-Al2O3 and carbonyl-derived Rh-Co/CeO2, in which the presence of iron oxide or Co can promote water-gas-shift reaction and significantly improve the SRE performance. On the other hand, adding 3 wt% CaO to Ni/Al2O3 can greatly improve the catalyst stability because the Ca modification not only increases Ni concentration on the Ni/Ca-Al2O3 surface and 3d valence electron density, but also facilitates the water adsorption and coke gasification via water-gas-shift. The availability of abundant surface OH groups helps the formation and conversion of adsorbed formate intermediate. Hence, ethanol reaction on Ca-Al2O3-supported Ni, Pt, Pd and Rh catalysts are found to follow the formate-intermediated pathway, a new reaction pathway alternative to the traditional acetate-interrnediated pathway.

Evaluation Performance of Different Types Catalysts of an Industrial Secondary Reformer Reactor in the Ammonia Plants

In this paper, the effect of catalyst shape and characteristics has been investigated where five types of a catalyst were examined under the same operation conditions, where catalysts are similar in the chemical properties (Ni/MgOAl2O3) but it's different in their physical properties in the catalyst section of secondary reformer. The secondary reformer involves continuation of the methane reforming reaction that began in the primary reformer to produce Nitrogen and Hydrogen in the ammonia plant. In order to evaluate performance of various types of catalysts in the secondary reformer reactor, mathematical model have been created. The mathematical model covers all aspects of major chemical kinetics, heat and mass transfer phenomena in the secondary reformer in the ammonia plant at steady state conditions. It aims to optimize the best catalyst from five types of catalyst of the secondary reformer reactor in the State Company of Fertilizers South Region in the Basra/Iraq. The mathematical model allows calculating the axial variations of compositions, temperature and pressure of the gases inside two reactors in series by using the atomic molar balance and adiabatic flame temperature in the combustion section while, in the catalyst section, they are predicted by using a one-dimensional heterogeneous catalytic reaction model. The analysis evaluation performance of the catalyst (RKS-2-7H') have good results than other the catalyst types (RKS - 2, ICI 54 - 2, RKS-2-7H”, RKS-2-7H”’) in catalyst zone of the secondary reformer.

授课与学科竞赛融合的工业催化课程教学改革

随着“新工科”理念的兴起,工程教育越来越重视学生的应用能力。作为化工专业的核心课程,工业催化课程旨在让学生掌握催化理论及其工艺应用。然而,传统教学模式在课程内容更新和实践应用方面存在不足。为应对这一挑战,本课程将课堂教学与学科竞赛有机结合,通过优化教学内容、组建学生项目团队和改进评价体系,增强课程的实际应用性。实施这一教学改革后,学生更好地将催化理论与实际工程应用相结合,显著提升了实践能力、创新水平和在化工类学科竞赛中的表现。

新工科背景下高校课程思政的实践与探索——以工业催化课程为例

随着中国经济的快速发展和科技创新的推动,新工科背景下的课程思政已成为教育改革的重要议题。该文以工业催化课程为例,通过实践和探索,探讨如何在该课程中融入思政教育的策略和方法。首先,介绍新工科背景下思政教育的重要性和必要性。然后,分析工业催化课程的特点和学生需求,提出将思政教育融入课程的理论基础。接下来,通过课程设计、教学方法和评估方式的改革,实现工业催化课程思政教育的有效融合。最后,总结实践经验和教改效果,并对未来的研究方向提出建议。

Hybrid structure of iron single atoms and metallic titanium for photothermal ethanol steam reforming

Photothermal ethanol steam reforming(ESR) is currently limited by low intrinsic activity and strong solar energy dissipation.Herein,we synthesized Fe single atoms supported on CeO_(2)(SA Fe-CeO_(2)) to exhibit excellent low-temperature ESR activity with a hydrogen production rate of 512 mmol g^(-1)h^(-1) at 350℃,becuase of the high oxidation state of Fe single atoms to weaken the reaction barrier of ethanol decomposition.Furthermore,a heterostructure of SA Fe-CeO_(2) and Ti foil could eliminate 66% of infrared radiation via the size effect,thus achieving a 3.5 sun-driven temperature of 347℃.Consequently,the heterostructure of SA Fe-CeO_(2) and Ti foil shows a hydrogen generation rate of 984 mmol g^(-1)h^(-1) of ESR and 11.31% of solar-to-hydrogen energy conversion efficiency,which outperforms other photothermal ethanol-hydrogen production systems.This study provides a new path for designing active catalytic sites and trapping light energy of photothermal catalysts.

基于化工专业工程教育认证背景下《工业催化》课程教学改革与探索

本文以工程教育认证为契机,以榆林学院化学工程与工艺专业核心课——《工业催化》课程为例,探讨了以学生为中心,以能力培养为目标的课程教学模式改革思路,主要包括课程体系构建、教学设计改革、考核评价机制优化等方面。通过教学目标达成度评价与反馈,做到教学质量持续改进,极大地提高了学生解决复杂工程问题的能力。

催化原理教学改革探析

现代催化科学与技术的发展日新月异,涉猎十分广泛,具有理论与实际联系紧密学科特点。为了提高《催化原理》课程的教学质量。本文从催化原理课程的教学准备、教学过程、教学反思和科研反哺等过程中不断地改进,激发学生对催化领域的向往,为催化科学的旺盛生命力添砖加瓦。