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Improving the catalytic performance of materials based on cerium oxide (CeO2) for the activation of methane (CH4) can be achieved through the following strategies: mixture of CeO2 with different oxides (e.g., CeO2–La2O3) and the use of particles with different sizes. In this study, we present a theoretical investigation of the initial CH4 dehydrogenation on (La2Ce2O7)n clusters, where n = 2, 4, and 6. Our framework relies on density functional theory calculations combined with the unity bond index–quadratic exponential potential approximation. Our results indicate that chemical species arising from the first dehydrogenation of CH4, that is, CH3 and H, bind through the formation of C–O and H–O bonds with the clusters, respectively. The coordination of the adsorption site and the chemical environment plays a crucial role in the magnitude of the adsorption energy; for example, species adsorb more strongly in the low-coordinated topO sites located close to the La atoms. Thus, it affects the activation energy barrier, which tends to be lower in configurations where the adsorption of the chemical species is stronger. During CH4 dehydrogenation, the CH3 radical can be present in a planar or tetrahedral configuration. Its conformation changes as a function of the charge transference between the molecule and the cluster, which depends on the CH3-cluster distance. Finally, we analyze the effects of the Hubbard effective parameter (Ueff) on adsorption properties, as the magnitude of localization of Ce f-states affects the hybridization of the interaction between the molecule and the clusters and hence the magnitude of the adsorption energies. We obtained a linear decrease in the adsorption energies by increasing the Ueff parameter; however, the activation energy is only slightly affected. [ABSTRACT FROM AUTHOR]

The catalytic dehydrogenation of methanol to give formaldehyde or formic acid, followed transfer hydrogenation and/or tandem (de)hydrogenation for the hydrogenation and C-methylation of carbonyls, offers advantages over traditional methods, including milder reaction conditions, improved safety, greater selectivity, and enhanced sustainability. This account provides a comprehensive overview of homogeneous catalysts reported for the transfer hydrogenation and C-methylation of various substrates, including ketones, chalcones, esters, and amides, using methanol as both a hydrogen donor and methylation source. We provide specific examples and mechanistic insights for each strategy, offering a thorough and concise overview of recent advancements from 2014 to 2024. 1 Introduction 2 Methanol Activation Strategies 3 Hydrogenation of Carbonyls 4 Methylation of Carbonyls 5 Outlook and Summary [ABSTRACT FROM AUTHOR]

Bicyclohexyl dehydrogenation using PtCrNi-containing catalysts supported on oxidized Sibunit carbon is studied as a key stage of hydrogen storage and evolution systems using liquid organic hydrogen carriers. It is shown that modifying platinum with nickel and chromium raises the specific activity of the catalyst considerably, relative to the evolution of hydrogen at a low content of the noble metal (0.1 wt % Pt). It is found that using an oxidized Sibunit carbon support to synthesize active supported Pt catalysts for bicyclohexyl dehydrogenation does not produce products of side reactions. [ABSTRACT FROM AUTHOR]

An anatase/TiO2(B) homojunction loaded with Au nanoparticles was synthesized, achieving a C2H6 yield rate of 170 μmol g−1 h−1 in a flow photoreactor. The homojunction reduces TiO2(B)'s strong oxidative ability, offering a more moderate environment for methane dehydrogenation, while Au aids in charge mitigation and methyl radical coupling. The catalyst highlights homojunction engineering and a ternary synergistic effect in photocatalytic CH4 coupling. [ABSTRACT FROM AUTHOR]

There has been significant interest in developing new catalytic systems to convert linear chain alkanes into olefins and aromatics. In the case of higher alkanes (≥C6), the production of aromatic compounds such as benzene‐toluene‐xylenes is highly desirable. However, as the length of the carbon chain increases, the dehydrogenation process becomes more complex, not only due to the challenges of C−H activation but also the need for selectivity towards the desired products by the possibility of side reactions such as isomerization and cracking. Here, we present a detailed analysis of the dehydroaromatization of n‐hexane, n‐heptane, and n‐octane, using PtSn intermetallic nanoparticles supported on SBA‐15 as the catalyst. Through in situ spectroscopic and kinetic analysis, we have probed the reaction kinetics and catalyst deactivation, and provided a mechanistic understanding of the dehydroaromatization process on the surface of the PtSn intermetallic nanoparticles. Introducing Sn has been shown to be crucial not only for enhancement of catalytic activity, but also for higher aromatics selectivity and stability on stream. Furthermore, the analysis of dehydroaromatization reaction rates of reactant and possible intermediates indicates that the dehydroaromatization of n‐hexane to benzene likely proceeds through initial dehydrogenation steps followed by ring closing. [ABSTRACT FROM AUTHOR]

Each step in the catalyst synthesis process plays an important role in tuning the catalyst structures. For zeolite‐supported nickel catalysts, we found the conventional calcination‐reduction method typically leads to the formation of large nickel particles, but a pre‐aging in hydrogen or nitrogen at a low temperature prior to final reduction can result in ultra‐small nickel nanoparticles in a metallic state. This pre‐aging treatment facilitates the interaction between Ni2+ cations and silanol nests on zeolite before the decomposition of the metal salt, leading to the formation of nanoparticles with an average diameter of ~1.2 nm. In contrast, the pre‐calcination in oxygen caused the Ni2+ aggregation before the decomposition of the metal salt precursor, yielding nickel nanoparticles larger than 5 nm. Given the structure sensitivity of nickel in cyclohexane dehydrogenation for hydrogen production, the ultra‐small nickel nanoparticles exhibited significantly enhanced activity and durability compared to previous nickel catalysts. [ABSTRACT FROM AUTHOR]

Using catalytic methane decomposition techniques to produce H2 could advance renewable energy development. Selecting the proper catalyst for this method is essential for efficient hydrogen production. We used reactive molecular simulations to examine methane's decomposition reaction and the formation of H2 molecules on a Ni (1 1 0) surface. The results show that the dissociation of H atoms on Ni (1 1 0) surfaces produced H2 molecules. The reaction reached saturation because the Ni (1 1 0) surface was covered by methane fragments. These exhibited enhanced adsorption as the H atoms’ dissociation intensified. As the number of hydrogen atoms bonded to methane fragments decreased, the adsorption energy of methane fragments decreased. [ABSTRACT FROM AUTHOR]

Formic acid (HCOOH) is a promising source of hydrogen energy that can be used to produce hydrogen in a more economical and ecological way. Formic acid is a simple carboxylic acid with a high hydrogen concentration and is generally stable, making it useful as a hydrogen transporter. Catalytic dehydrogenation is usually used to extract hydrogen from formic acid; this process releases hydrogen gas and yields carbon dioxide as a byproduct. Comparing this technology to conventional hydrogen generation methods, there are several benefits, such as the utilization of the formic acid handling infrastructure already in place and the possibility of a simpler integration into different energy systems. Notwithstanding, several obstacles persist, including enhancing the effectiveness of the dehydrogenation procedure and reducing the ecological consequences of the correlated carbon dioxide discharges. Catalysts, reaction conditions, and carbon collection and utilization methodologies are all being researched further. The development of Ru and Cu‐based catalysts for the catalytic breakdown of HCOOH into CO2 and H2 is the main topic of this account. Herein, the focus is on the kinetic studies of HCOOH dehydrogenation, encompassing mechanistic investigations that consider intermediate studies and DFT calculations. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carriers (LOHCs) are a promising option for hydrogen storage, but a high efficiency of the LOHC cycle is essential in order to serve as an attractive technology in the context of decarbonization. This paper presents different methods to optimize steady‐state operating points of a LOHC dehydrogenation (DH) reactor. For this purpose, an analytical model of a DH reactor is described, which is extended to a hybrid model (HM) to achieve sufficient model accuracy. The model quality is subsequently validated by measurements. For the optimization of the steady‐state operation point, a Bayesian optimization framework is presented and compared to classical model‐based optimization. The methods are evaluated with the HM as well as with experimental results. [ABSTRACT FROM AUTHOR]

We found that molybdenum carbide (Mo2C) can be applied as a novel and efficient heterogeneous catalyst for hydrogen transfer of anilines and alcohols to synthesize N-alkylamines. The results of experiments and DFT calculations demonstrate that Mo2C surface can reduce the energy barrier of the key step of alcohol dehydrogenation and generate a hydrogen spillover effect, thereby exhibiting outstanding catalytic performance. [ABSTRACT FROM AUTHOR]

The presence of alkali metals in flue gas can lead to catalyst poisoning, which can significantly impact the de-NOx efficiency of the catalyst. There is a lack of specific studies on the influence of potassium (K) poisoning on the efficiency of γ-Fe2O3. In this study, the mechanism of K poisoning on the γ-Fe2O3 surface was studied based on DFT, and the influence of K on molecular adsorption and SCR reaction process was analyzed. The results show that the K2O and KCl provide O, K, and Cl ions when deposited on the catalyst surface. The adsorption and dehydrogenation processes of NH3 were enhanced to varying degrees near the O and Cl iron sites, but the subsequent generation and decomposition of NH2NO were inhibited. On the sites near K cations, the adsorption, dehydrogenation, and subsequent SCR reaction processes of NH3 are hindered, and the adverse effects on the reaction are greater on the Fe sites closer to K. As well as the presence of K can to some extent promote the adsorption of NO and O2. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the activity of KIT‐6 supported nickel (Ni) and cobalt (Co) catalysts, and the effect of Co incorporation to the Ni@KIT‐6 catalyst in the formic acid (FA) dehydrogenation. Ni and Co are inexpensive and readily available non‐noble transition metals that are considered ideal for dehydrogenation reactions due to their high activity against C−C and C−H bond breaking. In this study, KIT‐6 supported catalysts were tested for hydrogen production from FA in a conventionally heated packed‐bed continuous‐flow system. N2 adsorption‐desorption isotherms of the samples were found to be consistent with Type‐IV according to the International Union of Pure and Applied Chemistry (IUPAC) classification. The introduction of metal loading resulted in the preservation of the mesoporous structure of the support material. X‐ray diffraction (XRD) patterns of the catalysts exhibited the characteristic amorphous silica structure. Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFT) analysis, Lewis acidity of Co‐based catalysts was found to be higher than the Ni‐based catalysts. The complete formic acid conversion was observed at 200–350 °C. The highest H2 selectivity was obtained with the 3Ni@KIT‐6 catalyst. The Co‐based catalysts exhibited relatively lower catalytic activity, which was linked to increased coke formation within these catalysts. [ABSTRACT FROM AUTHOR]

A typical feature that the LOHC technology shares with other types of chemical hydrogen storage is that the release of hydrogen from the carrier requires an input of heat. In many use cases where waste heat from external sources is not available (e.g. in heavy-duty mobility), this is seen as a major drawback. In this paper, we show that autothermal LOHC dehydrogenation offers a very attractive way to overcome this drawback. In detail, we demonstrate autothermal hydrogen release from dicyclohexylmethane using diphenylmethane oxidation to benzophenone as source of heat. The full storage cycle involves benzophenone hydrodeoxygenation to dicyclohexylmethane, dicyclohexylmethane dehydrogenation to diphenylmethane, and diphenylmethane oxidation to benzophenone. We studied both the individual reaction steps using pure feedstocks and the integral cycle in which the intermediates and by-products of each reaction remain in the system for the subsequent reaction step. Although no efforts have yet been made to develop special catalyst materials for this purpose, the results with the applied commercial hydrodeoxygenation (Pd/C), dehydrogenation (Pt on alumina) and partial oxidation (VO x /TiO 2) catalysts are already very promising. The storage cycle can be closed with high selectivity and with only minor total oxidation losses. The proposed concept of autothermal LOHC dehydrogenation offers the potential to increase the amount of useable hydrogen from a given amount of charged hydrogen carrier by up to 30%. • Autothermal dehydrogenation enables chemical hydrogen storage without external heat. • Dehydrogenation heat is provided through partial oxidation of the hydrogen carrier. • Regeneration takes place through hydrodeoxygenation at energy-rich locations. • Individual reaction steps and influencing parameters have been studied. • Full autothermal hydrogen storage cycle demonstrated for model system. [ABSTRACT FROM AUTHOR]

This study elucidates the impact of the types and blending ratios of low-carbon alkanes (methane and ethane, C1/C2) on the combustion and emission performance of NH₃ and analyzes the reasons for the differences in the effects of C1/C2 from the elementary reaction. The experimental and numerical analysis results show that C1/C2 reduces the temperature dependence of NH₃ oxidation and promotes the formation of combustion-promoting (CP) radicals. The concentration of CP is determined by the strength of the H-abstraction reactions of C1/C2. The initial H-abstraction product of C1, CH₃, exhibits reaction inertness, whereas the inert radicals of C2 (C₂H₄, C₂H₃, and C₂H₂) appear after three main H-abstraction steps. Additionally, C1/C2 intensifies the NH→N→NO reaction, worsening thermal-NO emissions; this study classifies it as a thermal-NO generation pathway. Although NH₂ and NH significantly reduce fuel-NO, their effect on thermal-NO is less pronounced. The consumption of thermal-NO primarily depends on the reverse direction of the reaction N 2 +O N + NO. • The introduction of C1/C2 reduces the temperature dependence of NH 3 oxidation reactions. • The dehydrogenation reactions of C1/C2 produce different types of inert radicals that limit subsequent dehydrogenation reactions. • C1's inert radicals form after the first dehydrogenation, while C2's form after the third dehydrogenation. • For the HC(O)/NH 3 , NH.→N→NO should be classified as one of the thermal-NO generation pathways. • Thermal-NO consumption depends on N accumulation, driving the reaction N 2 +O=N+NO. [ABSTRACT FROM AUTHOR]

High phosphorus Ni-P coatings, both unreinforced and modified by the addition of alumina (Al2O3) and zirconia (ZrO2) nanoparticles, were manufactured by electroless deposition technique and heat-treated with different temperature and duration schedules. The effect of dehydrogenation (200 °C for 2 h) and its combination with crystallization heat treatment was studied in terms of microstructural changes and wear resistance. The amorphous structure of the coatings was not altered by the introduction of both Al2O3 and ZrO2 nanoparticles, and the addition of 1.5 g/L of ZrO2 yielded the highest microhardness due to better particles dispersion. Dehydrogenation improved hardness because of the early stages of grain growth; however, the greatest improvement in hardness (+120% compared to unreinforced Ni-P) was obtained after annealing at 400 °C for 1 h, because of the microprecipitation of the Ni3P crystalline phase induced by thermal treatment. No detectable differences in hardness and microstructure were detected when annealing at 400 °C for 1 h with or without prior dehydrogenation; however, the dehydrogenated coatings exhibited a lower Young's modulus. ZrO2-reinforced coatings demonstrated improved wear resistance, and wear tests revealed that dehydrogenation is fundamental for lowering the coefficient of friction (−14%) and wear rate (−97%) when performed before annealing at 400 °C for 1 h. The analysis of the wear tracks showed that the non-dehydrogenated samples failed by complete coating delamination from the substrate, with abrasion identified as the predominant wear mechanism. Conversely, the dehydrogenated samples demonstrated better resistance due to the formation of a protective oxide layer, leading to an overall increase in the coating wear resistance. [ABSTRACT FROM AUTHOR]

The facile synthesis of the cationic dinuclear group 10 complexes [M2(PCP)2μ-Cl]+ (M = Ni, Pd, Pt) by transmetallation from a simple Ga precursor is reported (PCP = 2,6-(Ph2P)C6H3). Their use for the catalysed dehydrogenation of Me2NHBH3 shows that Ni has a higher reactivity than Pt, whereas Pd is inactive. [ABSTRACT FROM AUTHOR]

An MgH2–anthraquinone carbonization product composite (denoted as MgH2–ACP composites) was successfully prepared through a hydrogenation combustion and mechanical ball-milling method using the original Mg powder to simultaneously achieve modification via in situ-formed amorphous carbon. The amorphous carbon derived from the combustion of carbonic compounds significantly enhanced the hydrogen-absorption and -desorption performances of MgH2. Results revealed that the onset decomposition temperature of the MgH2–ACP composite decreased from 638 K to 587 K in the dehydrogenation stage. Moreover, the MgH2–ACP sample delivered dehydrogenation capacities of 3.525 wt% at 598 K, whereas the as-milled MgH2 decomposed only 0.763 wt% at the same temperature. The activation energies calculated using Kissinger analysis in the dehydrogenation process of MgH2 were lowered by about 57.5 kJ mol−1. For the absorption kinetic measurements at 473 K, the MgH2-ACP sample could uptake about 4.629 wt% of H2 in 3200 s compared to 1.804 wt% taken up by the as-milled MgH2. The in situ-formed amorphous carbon and MgO were confirmed as the active species that contributed to the enhancement of hydrogen-storage properties of the composite. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Catalytic dehydrogenation, with its exceptional atom economy and chemoselectivity, offers a highly desirable yet challenging approach for converting multiple environmentally friendly alcohols into crucial molecules. Furthermore, the utilization of catalysts based on abundant elements found on Earth for alcohol dehydrogenation to produce acryl ketone holds significant promise as a versatile strategy in synthesizing key building blocks for numerous pharmaceutical applications. The present study describes a practical Co‐catalyzed cascade dehydrogenative Claisen condensation of secondary alcohols with esters, facilitating the synthesis of a wide range of 3‐hydroxy‐prop‐2‐en‐1‐ones. We introduce a catalytic system based on novel and scalable indazole NNP‐ligands coordinated to cobalt for efficient dehydrogenations of secondary alcohols, and propose a plausible reaction mechanism supported by control experiments and labeling studies. Notably, it allows for the streamlined synthesis of multiple pharmaceuticals in one‐pot. [ABSTRACT FROM AUTHOR]

MgH 2 is one of the ideal hydrogen storage materials because of its high hydrogen storage density, but the thermodynamic stability and slow kinetics of Mg/MgH 2 system hinder its practical application. Transition metal catalyst doping has become an important strategy to improve the hydrogen storage kinetics of MgH 2. In this work, FeNi 3 @CS was prepared by solvothermal method with carbon spheres (CS) as the support, and introduced into Mg/MgH 2 system to prepare MgH 2 –FeNi 3 @CS composite. The initial dehydrogenation temperature of MgH 2 –FeNi 3 @CS composite is 565 K, which is 100 K lower than additive-free MgH 2. At 423 K, MgH 2 –FeNi 3 @CS composite could absorb 4.5 wt% H 2 , while the hydrogen absorption capacity of MgH 2 without additives is only 2.0 wt%. After 10 cycles, the hydrogenation and dehydrogenation capacity could be maintained at 5.6 wt% and 4.5 wt%, respectively. In addition, the activation energy of MgH 2 –FeNi 3 @CS composite decreased by 52 kJ/mol compared with MgH 2. FeNi 3 was in situ converted to Mg 2 NiH 4 and Fe after hydrogenation-ball milling, which were considered as the catalytic active substances in Mg/MgH 2 system. The synergistic catalysis of Mg 2 Ni/Mg 2 NiH 4 , Fe and carbon materials has a positive effect on improving the hydrogen storage performance of Mg/MgH 2 system. • FeNi 3 nanoparticles loaded with carbon spheres (CS) are synthesized. • The MgNi 2 /Mg 2 NiH 4 –Fe/C heterogeneous catalytic system was constructed. • The MgH 2 –FeNi 3 @CS composite can absorb 4.5 wt% hydrogen within 1 h at 423 K. • The initial dehydrogenation temperature of MgH 2 – FeNi 3 @CS composite is 565 K. [ABSTRACT FROM AUTHOR]

To reveal the catalytic function of Brønsted acid sites (BAS) and different Zn Lewis acid sites (LAS) over SSZ‐39 and Zn modified SSZ‐39 in the direct dehydrogenation of propane (DHP) and CO2‐mediated oxidative dehydrogenation (CO2‐ODHP) to propylene, a series of Zn‐modified H(Na)SSZ‐39 catalysts with various Zn loadings was prepared and conducted comparative studies between DHP and CO2‐ODHP. Detailed characterization results reveal the Zn‐loading‐dependent formation of Zn sites, primarily including Zn2+ and [Zn−O−Zn]2+, as well as their contributions in generating Lewis acid sites while neutralizing Brønsted acid sites of HSSZ‐39, namely bridged Si(OH)Al groups. In DHP, in comparison to bare HSSZ‐39, Zn/HSSZ‐39 catalysts exhibited a significantly enhanced C3H8 conversion. The presence of CO2 even further promoted C3H8 conversion in comparison to DHP. Given the above observations, we prepared Zn/NaSSZ‐39, in which the incorporation of Na further enriches the Lewis acid sites while neutralizing Brønsted acid sites of zeolite. Zn/NaSSZ‐39 even outperforms Zn/HSSZ‐39 catalysts with almost doubled C3H6 yield for CO2‐ODHP. The BAS has a poor CO2‐ODHP performance but can enhance the CO2 conversion towards CO significantly, while the Zn LAS is favorable for the CO2‐ODHP reaction, and plausible reaction paths of CO2‐ODHP on active sites are proposed. [ABSTRACT FROM AUTHOR]

The combined use of O2 and CO2 as oxidizing agents in the oxidative coupling of methane (OCM) has been assessed over two representative OCM catalysts, i. e., La−Sr/CaO and NaMnW/SiO2, under a wide range of inlet O2 and CO2 concentrations. The overall impact of CO2 was found to depend on the operating conditions and the catalyst used. At O2‐rich conditions, a negative effect of CO2 was observed on C2 selectivity. At O2‐lean conditions, a positive effect of CO2 on both catalysts was observed, likely originating from an enhanced dehydrogenation of C2H6 to C2H4 and limited deep oxidation of the involving hydrocarbons and reaction intermediates. The behavior induced by CO2 is attributed to its mild oxidizing ability and interactions with the catalysts. The enhanced dehydrogenation of C2H6 was observed and confirmed by specific tests with a CO2 and C2H6 feed. Well‐controlled CO2 addition improved the value of the OCM product mixture, mainly due to a 9 % increase in C2H4 and a 19 % increase in CO selectivity, resulting in a 25 % reduction of CO2 at the outlet over the La−Sr/CaO catalyst. These findings provide new insight into the CO2 effect on OCM and the data to translate this research into OCM process alternatives. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting for hydrogen evolution is a highly topical subject in academic research and a promising approach for sustainable fuel production from solar energy. Due to the mismatched energy diagram of the photosensitizer (especially semiconductor‐based materials where band‐edge engineering is not trivial) and the redox potential of the half‐reactions of water splitting, photocatalytic H2 generation from water splitting is usually accelerated by the addition of hole scavengers, i.e. sacrificial reagents such as alcohols, amines, and thiols. However, the source of the protons of the evolved H2 is often neglected, and it is questionable whether such systems are really water splitting. Here, we discuss recent reports on sacrificial reagent‐assisted photocatalytic water splitting and present our recent findings, which showcase that the sacrificial reagent in the investigated photocatalytic water splitting systems inherently undergoes acceptorless dehydrogenation, with H2O serving as the proton shuttle, the amount of which doesn't change during the course of the reaction. [ABSTRACT FROM AUTHOR]

An MgH2–anthraquinone carbonization product composite (denoted as MgH2–ACP composites) was successfully prepared through a hydrogenation combustion and mechanical ball-milling method using the original Mg powder to simultaneously achieve modification via in situ-formed amorphous carbon. The amorphous carbon derived from the combustion of carbonic compounds significantly enhanced the hydrogen-absorption and -desorption performances of MgH2. Results revealed that the onset decomposition temperature of the MgH2–ACP composite decreased from 638 K to 587 K in the dehydrogenation stage. Moreover, the MgH2–ACP sample delivered dehydrogenation capacities of 3.525 wt% at 598 K, whereas the as-milled MgH2 decomposed only 0.763 wt% at the same temperature. The activation energies calculated using Kissinger analysis in the dehydrogenation process of MgH2 were lowered by about 57.5 kJ mol−1. For the absorption kinetic measurements at 473 K, the MgH2-ACP sample could uptake about 4.629 wt% of H2 in 3200 s compared to 1.804 wt% taken up by the as-milled MgH2. The in situ-formed amorphous carbon and MgO were confirmed as the active species that contributed to the enhancement of hydrogen-storage properties of the composite. [ABSTRACT FROM AUTHOR]

The facile synthesis of the cationic dinuclear group 10 complexes [M2(PCP)2μ-Cl]+ (M = Ni, Pd, Pt) by transmetallation from a simple Ga precursor is reported (PCP = 2,6-(Ph2P)C6H3). Their use for the catalysed dehydrogenation of Me2NHBH3 shows that Ni has a higher reactivity than Pt, whereas Pd is inactive. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Catalytic dehydrogenation, with its exceptional atom economy and chemoselectivity, offers a highly desirable yet challenging approach for converting multiple environmentally friendly alcohols into crucial molecules. Furthermore, the utilization of catalysts based on abundant elements found on Earth for alcohol dehydrogenation to produce acryl ketone holds significant promise as a versatile strategy in synthesizing key building blocks for numerous pharmaceutical applications. The present study describes a practical Co‐catalyzed cascade dehydrogenative Claisen condensation of secondary alcohols with esters, facilitating the synthesis of a wide range of 3‐hydroxy‐prop‐2‐en‐1‐ones. We introduce a catalytic system based on novel and scalable indazole NNP‐ligands coordinated to cobalt for efficient dehydrogenations of secondary alcohols, and propose a plausible reaction mechanism supported by control experiments and labeling studies. Notably, it allows for the streamlined synthesis of multiple pharmaceuticals in one‐pot. [ABSTRACT FROM AUTHOR]

Alumina‐supported PtSn catalysts have been industrialized as the major catalysts for propane dehydrogenation, where Sn serves as an essential promoter. Herein, we synthesized a variety of Sn‐doped alumina supports by regulating the precipitation order of Sn and Al precursors as follows: Sn precursor precipitated before Al, coprecipitated with Al, precipitated immediately after Al, or precipitates after 2 h of Al. The effect of Sn promoter on the surface acidic properties of alumina and, ultimately, on propane dehydrogenation was further investigated. The Sn species introduced by coprecipitation in alumina created additional surface strong acid sites, attributed to more Sn4+ species on the surface, which are able to remain stable during the subsequent treatment. Consequently, the coprecipitated Sn species in the corresponding catalyst donate more electrons to Pt and reduce the metal particle size. As a result, the catalyst with Pt supported on the coprecipitated support (Sn+Al) exhibits superior initial propane conversion (43.2%) and stability (kd = 0.035 h−1). This study provides new insight into the interaction between the two key components, tin promoter and alumina support, of Pt/Sn‐Al2O3 catalysts. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carriers (LOHCs) offer a promising solution for global hydrogen infrastructure, but their practical application faces two key challenges: sluggish dehydrogenation processes and the reliance on catalysts with high noble metal loadings. This study presents a scalable approach to reduce noble metal usage while maintaining high catalytic activity. We synthesized an ultralow Pt content (0.1 wt %) catalyst using γ‐Al2O3‐based pellet support with atomic layer deposition (ALD) of TiO2. Advanced characterization techniques reveal that the thin ALD‐TiO2 shell provides a heterogeneous interface, confining electronically rich Pt‐nanoparticle ensembles. The catalyst outperforms both equivalent Pt‐content catalysts and a commercial 0.5 wt % Pt/γ‐Al2O3 catalyst in homocyclic LOHC dehydrogenation. This study provides insights into the beneficial role of ALD‐engineered interfaces for catalytic supports and offers an efficient approach for scalable production of low‐noble‐metal‐content catalysts, with implications for various catalytic processes. [ABSTRACT FROM AUTHOR]

HPSB (Hydrolysis Product of Sodium Borohydride) hydrogen storage material is a kind of porous lamellar structural material developed by our research group. Due to the special structure of this material, it can absorb hydrogen at room temperature, hydrogen absorption pressure is 2–4 MPa, and hydrogen absorption time is 2–5 min. The main preparation method used in the experiment is hydrolysis. The main raw material is sodium borohydride, and the reaction temperature is 30 °C. In this experiment, in order to improve the hydrogen storage performance of HPSB hydrogen storage material, Co–B and Sm 2 O 3 were introduced as catalysts during the preparation of HPSB. The results show that the amount of Sm 2 O 3 and the ratio of Sm 2 O 3 to Co–B have obvious influence on the hydrogen storage performance of HPSB. In addition, according to the results of SEM analysis, the amount of Sm 2 O 3 and the ratio of Sm 2 O 3 to Co–B also have obvious effects on the microstructure of HPSB hydrogen storage materials. The sample with a doping amount of 4 wt% and a ratio of Sm 2 O 3 to Co–B of 4:6 can release 2.17 wt% H 2. • The catalyst Co–B/Sm 2 O 3 can improve the hydrogen storage performance of HPSB. • Co–B/Sm 2 O 3 doping 4 wt% and ratio 4:6 shows the best dehydrogenation performance. • The maximum total dehydrogenation amount of the Co–B/Sm 2 O 3 doped sample is 2.17 wt%. [ABSTRACT FROM AUTHOR]

Understanding the properties of solid-state materials at the nanoscale is a crucial scientific endeavor in the pursuit of a sustainable energy future. Since magnesium hydride is the most practical material for hydrogen storage, research is still ongoing to reduce the enthalpy for dehydrogenation. In this computational theory, we systematically investigated the enthalpy of dehydrogenation of Mg n H m nanoclusters of different sizes (0.5–2.8 nm) through density functional theory (DFT) and ab-initio molecular dynamic (AIMD) simulations. Our results revealed that increasing the Mg n H m nanocluster size can remarkably improve the formation energy compared to the MgH 2 -bulk stabilization; the formation energy shifted from −65.12 kJ/mol for (0.5 nm)-Mg n H m nanocluster to −51.37 kJ/mol for (2.8 nm)-Mg n H m nanocluster. As compared to bulk phase, the lower stability of the nanoclusters indicates that it is much easier to desorb hydrogen from the surface. According to the effects of compressive/tensile strains, (2.8 nm)-Mg n H m nanocluster does not improve the dehydrogenation temperature in the desired direction. Unlike metal doping, 9.10%@Ni and 10.14%@V-doped (2.8 nm)-Mg n H m nanocluster exhibit formation energies of −47.27 and −46.34 kJ/mol with calculated desorption temperatures of 362.89 and 355.75 K, respectively, which ensures the room temperature applicability of this hydrogen storage material. [Display omitted] • The size effect of Mg n H m nanoclusters on thermodynamic properties through ab initio density functional calculations. • The compressive/tensile strains on the dehydrogenation properties of (2.8 nm)-Mg n H m are briefly reviewed. • Discovering Ni/V-doped system efficiency, reducing dehydrogenation temperature, boosting hydrogen storage performance. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carrier (LOHC) technology has unique advantages in hydrogen storage and transportation. However, the lack of research on the continuous dehydrogenation process of LOHCs has hindered the design and application of industrial dehydrogenation processes. In this work, a highly active dehydrogenation catalyst 1.5 wt% Pd/activated carbon (Pd/C) and a commercial catalyst 5 wt% Pd/Al2O3 were used for the continuous dehydrogenation of dodecahydro‐N‐ethylcarbazole (12H‐NEC). Based on a tubular reactor and lab‐scale apparatus, 1.5 wt% Pd/C catalyst achieved a maximum dehydrogenation conversion of 98.3% and a maximum NEC selectivity of 95.3%, while dehydrogenation conversion and NEC selectivity with 5 wt% Pd/Al2O3 were 98.3% and 97.6%, respectively. It showed the equally excellent performance between Pd/C and Pd/Al2O3, and the former has less Pd loading than the latter, with the potential of reducing the production cost of the dehydrogenation catalyst. The dehydrogenation results also indicated the difference in catalytic performance between the two kinds of catalysts. The obtained kinetics data were analyzed, and the dynamics of continuous dehydrogenation were studied to provide fundamental information for dehydrogenation scale‐up. [ABSTRACT FROM AUTHOR]

The dehydrogenation of n-butane to butenes is a crucial process for producing valuable petrochemical intermediates. This study explores the role of oxyphilic metal promoters (Sn, Zn, and Ga) in enhancing the performance and stability of Pt@MFI catalysts for n-butane dehydrogenation. The presence of Sn in the catalyst inhibits the agglomeration of Pt clusters, maintaining their subnanometric particle size. PtSn@MFI exhibits superior stability and selectivity for butenes while suppressing cracking reactions, with selectivity for C1–C3 products as low as 2.1% at 550 °C compared to over 30.5% for Pt@MFI. Using a combination of high-angle annular dark-field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and Raman spectroscopy, we examined the structural and electronic properties of the catalysts. Our findings reveal that Zn tends to consume hydroxyl groups and substitute framework sites, and Ga induces more defective sites in the zeolite structure. In contrast, the interaction between SnOx and the zeolite framework does not depend on reactions with hydroxyl groups. The incorporation of Sn significantly prevents Pt particle agglomeration, maintaining smaller Pt particle sizes and reducing coke formation compared to Zn and Ga promoters. Theoretical calculations showed that Sn increases the positive charge on Pt clusters, enhancing their interaction with the zeolite framework and reducing sintering, albeit with a slight increase in the energy barrier for C-H activation. These results underscore the dual benefits of Sn as a promoter, offering enhanced structural stability and reduced coke formation, thus paving the way for the rational design of more effective and durable catalysts for alkane dehydrogenation and other high-value chemical processes. [ABSTRACT FROM AUTHOR]

Nitrogen-containing aromatic compounds are ubiquitous in nature. They often exhibit a wide range of biological activities. Therefore, chemists have been studying on the preparation of them for a long time as well as developing various methods for their derivatization. Recently, the direct oxidation of nonaromatic cyclicsubstrates to prepare selectively substituted aromatics has been one of research focuses. In which, the functionalized aromatics could be obtained via C-C, C-N, C-S and C-Se bonds formation without the directing groups in one step. This paper reviews the recent progress in the construction of functional quinoline and indole by this method, and proposes future development prospects in this field. [ABSTRACT FROM AUTHOR]

Restructuring the current energy industry towards sustainability requires transitioning from carbon based to renewable energy sources, reducing CO2 emissions. Hydrogen, is considered a significant clean energy carrier. However, it faces challenges in transportation and storage due to its high reactivity, flammability, and low density under ambient conditions. Liquid organic hydrogen carriers offer a solution for storing hydrogen because they allow for the economical and practical storage of organic compounds in regular vessels through hydrogenation and dehydrogenation. This review evaluates several hydrogen technologies aimed at addressing the challenges associated with hydrogen transportation and its economic viablity. The discussion delves into exploring the catalysts and their activity in the context of catalysts′ development. This review highlights the pivotal role of various catalyst materials in enhancing the hydrogenation and dehydrogenation activities of multiple LOHC systems, including benzene/cyclohexane, toluene/methylcyclohexane (MCH), N‐ethylcarbazole (NEC)/dodecahydro‐N‐ethylcarbazole (H12‐NEC), and dibenzyltoluene (DBT)/perhydrodibenzyltoluene (H18‐DBT). By exploring the catalytic properties of noble metals, transition metals, and multimetallic catalysts, the review provides valuable insights into their design and optimization. Also, the discussion revolved around the implementation of a hydrogen economy on a global scale, with a particular focus on the plans pertaining to Saudi Arabia and the GCC (Gulf Cooperation Council) countries. The review lays out the challenges this technology will face, including the need to increase its H2 capacity, reduce energy consumption by providing solutions, and guarantee the thermal stability of the materials. [ABSTRACT FROM AUTHOR]

In situ X-ray diffraction and Raman spectroscopy of a synthetic whitlockite, Ca9Mg(PO3OH) (PO4)6, have been conducted at high pressures or high temperatures. The results show that whitlockite is stable up to ~15 GPa at ambient temperature and undergoes a thermally induced dehydrogenation to merrillite above 973 K at ambient pressure. The obtained pressure-volume data were fitted using a third-order Birch-Murnaghan equation of state, yielding an isothermal bulk modulus of K0 = 79(4) GPa with a pressure derivative of K 0 ′ = 4.3(6). When K 0 ′ was fixed at 4, the refined isothermal bulk modulus was 81(1) GPa. The volumetric thermal expansion coefficient (αV) is 4.05(8) × 10-5 K−1, and the axial thermal expansion coefficients (αa and αc) are 1.07(5) × 10−5 K−1 and 1.91(6) × 10−5 K−1. Both compressibility and thermal expansion show an axial anisotropy. The effects of pressure and temperature on the Raman spectra of whitlockite have been quantitatively analyzed. The isothermal and isobaric mode Grüneisen parameters and the intrinsic anharmonic mode parameters of whitlockite were derived. Some amounts of OH−-bearing whitlockite may be preserved in meteorites if whitlockite undergoes a low-temperature process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pd/DUT-67-PZDC(10) catalyst with highly dispersed Pd NPs was prepared. • The hierarchically microporous structural property of the DUT-67-PZDC support is beneficial for the stabilization of Pd NPs. • The dual N sites on the DUT-67-PZDC(10) support could act as excellent proton buffers to stimulate the O-H bond cleavage in FA. • The ultrasmall size (1.7 nm) and high dispersion of Pd NPs could expose more catalytic active sites. • The Pd/DUT-67-PZDC(10) catalyst shows an initial TOF value of 2572h−1, 100 % FA conversion and H 2 selectivity, and excellent stability at 60 °C. The highly dispersed ultrasmall palladium nanoparticles (Pd NPs) (1.7 nm) were successfully immobilized on a N -containing metal–organic framework (MOF, DUT-67-PZDC) using a co-reduction method, and it is used as an excellent catalyst for formic acid dehydrogenation (FAD). The optimized catalyst Pd/DUT-67-PZDC(10, 10 wt% Pd loading) shows 100% hydrogen (H 2) selectivity and formic acid (FA) conversion at 60 °C, and the commendable initial turnover frequency (TOF) values of 2572 h−1 with the sodium formate (SF) as an additive and 1059 h−1 even without SF, which is better than most reported MOF supported Pd monometallic heterogeneous catalysts. The activation energy (Ea) of FAD is 43.2 KJ/mol, which is lower than most heterogeneous catalysts. In addition, the optimized catalyst Pd/DUT-67-PZDC(10) maintained good stability over five consecutive runs, demonstrating only minimal decline in catalytic activity. The outstanding catalytic performance could be ascribed to the synergistic corporations of the unique structure of DUT-67-PZDC carrier with hierarchical pore characteristic, the metal-support interaction (MSI) between the active Pd NPs and DUT-67-PZDC, the highly dispersed Pd NPs with ultrafine size serve as the catalytic active site, as well as the N sites on the support could act as the proton buffers. This work provides a new paradigm for the efficient H 2 production of FAD by constructing highly active heterogeneous Pd-based catalysts using MOF supports. [ABSTRACT FROM AUTHOR]

Bimetallic Cu and Co nanoparticles were prepared using the polyol process. The nature of the polyol was found to be decisive to control the distribution of the two metals within the particles, resulting in either core‐shell or quasi‐alloyed structures, as shown by chemical analysis at the single particle level. The particles can be prepared over the entire composition range with a very good control of the Cu/Co molar ratio. The introduction of Cu in the synthetic system allows decreasing significantly the mean size of the resulting particles. The two sets of particles were used as unsupported catalysts for the solvent‐free acceptorless dehydrogenation of octan‐2‐ol. Very good ketone yields were measured when using the quasi‐alloyed particles while lower activities were obtained with core‐shell structures. The Cu25Co75 quasi‐alloyed catalyst could be recycled at least ten times without a significant loss in catalytic activity and particle‐scale chemical analyses confirmed that the recovered particles are still alloyed with no observed demixing. The catalytic results are discussed in the light of different exposed metal surface areas and possible synergetic effects using theoretical predictions. [ABSTRACT FROM AUTHOR]

Multiple phase transformations were carried out during dehydrogenation process of TiH2-based powder metallurgy. The influence of phase transformation on the microstructure is highly worthy of attention. In situ synchrotron radiation was employed to investigate the phase transformation sequence of TiH2 powder compact during the vacuum sintering process. It was found that a transformation route TiH1.971 → TiH2 + TiH + TiH0.71 + α(H) → TiH + TiH0.71 + α(H) → TiH + TiH0.71 + α(H) + β(H) → α(H) → α took place, resulting in an equiaxed microstructure. Increasing heating rate and avoiding the intense dehydrogenation to retain hydrogen-rich β (β(H)) and TiHx aciculae at the interfaces is found to be a feasible method to fabricate hierarchical α-Ti structures. A fully dense fine martensitic microstructure was produced after fast heating the TiH2 powder compact to 1100 °C and an immediate hot extrusion. Subsequently, by vacuum annealing treatment at 700 °C, composite α/βt lamellar structures were generated and a simultaneously enhanced tensile strength of 746 MPa and excellent elongation to fracture of 33.8% were achieved. It is suggested that adjusting the dehydrogenation reactions of TiH2-based powder metallurgy is conductive to generating hierarchical lamellar structures with a highly promising combination of strength and ductility for pure Ti. [ABSTRACT FROM AUTHOR]

The reaction of N,N‐bis(2‐(diisopropylphosphaneyl)ethyl)prop‐2‐yn‐1‐amine 1 with [Ru(CO)ClH(PPh3)3] leads to the formation of a new class of cyclometallated PNPC pincer complexes. Several examples of this class of compounds are synthesized and characterized. They, specifically complexes 2 and 3, show good to excellent activity and selectivity in additive‐free formic acid dehydrogenation, and transfer (de)hydrogenation reactions of different functional groups (ketone, alkyne, and alcohol). Theoretical and experimental studies reveal two competing pathways for the dehydrogenation of formic acid. The Ru‐H pathway proceeds via the coordination site trans to the propylene arm of the ligand, whereas in the Ru‐C pathway, a de‐coordination of the propylene arm is observed. [ABSTRACT FROM AUTHOR]

In this paper, petal sheet layered Co-Al bimetallic hydroxides were prepared using the hydrothermal method using methanol as a solvent. Pt/Co-Al-O catalysts were produced after the impregnation method and H 2 reduction. This catalyst was applied to the dehydrogenation reaction process of methylcyclohexane to toluene. A fixed-bed reaction device carried out comparative tests of this series of catalysts, and the effect of Co addition on the performance of Pt/Co-Al-O catalysts was investigated in detail. Among them, the Pt/Co 3 -Al 1 -O catalyst showed the best performance with high toluene selectivity throughout the dehydrogenation process. The MCH conversion started to be greater than 90% at 330 °C, and the hydrogenolysis rate was 262.7 mmol/g Pt /min. The conversion gradually increased with the reaction temperature, and the conversion could reach 99.5% at 410 °C. The appropriate introduction of Co element can reduce the excessive strong acidic sites of Al 2 O 3 itself and retain a certain number of weak acidic sites, while the bimetallic hydroxide carrier improves the dispersibility of the active component, reduces its particle size, and forms a certain strong interaction between the carrier and Pt. The final conversion of the catalyst decreased by about 2% in the 100 h stability test at 380 °C, which indicated that the Pt/Co 3 –Al 1 –O catalyst had strong coking resistance and good stability. These results indicate that the Pt/Co–Al–O series catalysts have potential industrial applications in hydrogen energy utilization. [Display omitted] • First application of Co–Al bimetallic hydroxide carriers as MCH dehydrogenation catalysts. • Preparation of Co–Al-LDH with special morphology to promote dehydrogenation reaction. • Prepared Pt/Co–Al–O catalysts and compared the effects of the ratio of Co and Al on the performance of the catalysts. [ABSTRACT FROM AUTHOR]

The transformation of alcohols to important classes of compounds is a central topic in chemistry because they are abundant, renewable, and attractive building blocks. The alkali‐mediated/catalyzed borrowing hydrogen and aerobic dehydrogenation processes of alcohols open a new and sustainable access for the alcohol conversion under transition‐metal‐free conditions. In this review, we summarize the recent alkali‐mediated/catalyzed sequential reactions involving the borrowing hydrogen and aerobic dehydrogenation processes of alcohols. Furthermore, this review not only introduces the tentative pathways of these transformations, but also discusses the role of alkali, solvent effects, and substrate reactivity on these reactions. [ABSTRACT FROM AUTHOR]

Direct aromatization of cyclohexanones to synthesize substituted phenols represents a significant challenge in modern synthetic chemistry. Herein, we describe a novel ene‐reductase (TsER) catalytic system that converts substituted cyclohexanones into the corresponding phenols. This process involves the successive dehydrogenation of two saturated carbon‐carbon bonds within the six‐membered ring of cyclohexanones and utilizes molecular oxygen to drive the reaction cycle. It demonstrates a versatile and efficient approach for the synthesis of substituted phenols, providing a valuable complement to existing chemical methodologies. [ABSTRACT FROM AUTHOR]

Azo compounds with a high density, high enthalpy, and excellent detonation performance have received increasing research attention. The conventional method of chemical dehydrogenation that is used to form azo compounds involves the use of strong oxidants, resulting in environmental pollution. Electrochemical organic synthesis is considered an old method and a new technology. In this work, azofurazan tetrazole {H2 AzFT; 5,5′-[diazene-1,2-diylbis(1,2,5-oxadiazole-4,3-diyl)]bis-1 H -tetrazole} and azofurazan hydroxytetrazole (H2 AzFTO) were synthesized by a green and efficient electrochemical dehydrogenation coupling of 5-(4-aminofurazan-3-yl)-1 H -tetrazole and 5-(4-aminofurazan-3-yl)-1-hydroxytetrazole, respectively. The structures of H2 AzFT and (NH4)2 AzFTO were fully characterized by infrared spectroscopy, nuclear magnetic resonance, and elemental analysis, and their thermal stabilities were determined by differential thermal analysis. [ABSTRACT FROM AUTHOR]

A unique bifunctional catalyst comprised of acid site containing, hierarchical ZSM‐5 (contains acid sites) supported RuCo bimetal, was synthesized using a facile incipient wetness impregnation method. The synergistic interaction between zeolite acid sites and bimetals of this bifunctional material significantly improves its performance as a catalyst of hydrogen producing, dehydrogenation of ammonia borane. [ABSTRACT FROM AUTHOR]

Propane dehydrogenation (PDH) is crucial for propylene production, but commercially employed Pt‐based catalysts face susceptibility to deactivation due to the Pt sintering during reaction and regeneration steps. Here, we report a SiO2 supported nanometric (MnCoCuZnPt) high‐entropy PDH catalyst with high activity and stability. The catalyst exhibited a super high propane conversion of 56.6 % with 94 % selectivity of propylene at 600 °C. The propylene productivity reached 68.5 molC3H6 ⋅ gPt−1 ⋅ h−1, nearly three times that of Pt/SiO2 (23.5 molC3H6 ⋅ gPt−1 ⋅ h−1) under a weight hourly space velocity of 60 h−1. In a high‐entropy nanoparticle, Pt atoms were atomically dispersed through coordination with other metals and exhibited a positive charge, thereby showcasing remarkable catalytic activity. The high‐entropy effect contributes to the catalyst a superior stability with a low deactivation constant of 0.0004 h−1 during 200 hours of reaction under the industrial gas composition at 550 °C. Such high‐entropy PDH catalyst is easy regenerated through simple air combustion of deposited coke. After the fourth consecutive regeneration cycle, satisfactory catalytic stability was observed, and the element distribution of spent catalysts almost returned to their initial state, with no detectable Pt sintering. This work provides new insights into designing active, stable, and regenerable novel PDH catalysts. [ABSTRACT FROM AUTHOR]

[Cp*Ir(R‐pica)Cl] (Cp*=pentamethylcyclopentadienyl anion, pica=2‐picolineamidate) complexes bearing carbohydrate substituents on the amide nitrogen atom (R=methyl‐β‐D‐gluco‐pyranosid‐2‐yl, 1; methyl‐3,4,6‐tri‐O‐acetyl‐β‐D‐glucopyranosid‐2‐yl, 2) were tested as catalysts for formic acid dehydrogenation in water. TOFMAX values over 12000 h−1 and 50000 h−1 were achieved at 333 K for 1 and 2, respectively, with TON values over 35000 for both catalysts. Comparison with the simpler cyclohexyl‐substituted analogue (3) indicated that glucosyl‐based complexes are much better performing under the same experimental conditions (TOFMAX=5144 h−1, TON=5000 at pH 2.5 for 3) owing to a lower tendency to isomerize to the less active k2‐N,O isomer upon protonation. The 5‐fold increase in TOFMAX observed for 2 with respect to 1 is reasonably due to an optimal steric protection by the acetyl substituent, which may prevent unproductive inner‐sphere reactivity. These results showcase a powerful strategy for the inhibition of the common deactivation pathways of [Cp*Ir(R‐pica)X] catalysts for FA dehydrogenation, paving the way for the development of better performing hydrogen storage systems. [ABSTRACT FROM AUTHOR]

Efficient approaches toward the synthesis of quinazolines and dihydroisoquinolines have been developed through copper‐catalyzed aerobic oxidative dehydrogenation of N‐heterocycles. The dehydrogenation was achieved through copper‐catalyzed aerobic oxidative dehydrogenation and azodicarboxylate esters‐mediated dehydrogenation of amines. Azodicarboxylate esters could be regenerated from copper‐catalyzed dehydrogenation of corresponding hydrazodicarboxylate esters, which made this catalytic dehydrogenation process more efficient and reactive. [ABSTRACT FROM AUTHOR]

In this study, body-centered-cubic Ti 24 V 18 Nb 6 Cr 12 high entropy alloy (HEA) is selected as the matrix to design Mg–Ti–V–Nb–Cr lightweight HEAs. Based on first-principles calculations, the hydrogen storage properties of a series of Mg–Ti–V–Nb–Cr HEAs are systematically investigated. The designed Mg-based HEAs are found to be stable after hydrogenation and exhibit high gravimetric hydrogen storage capacities (HSCs). Particularly, the gravimetric HSC of Mg 6 Ti 24 V 18 Cr 12 HEA is as high as 4.091 wt%. Besides, the dehydrogenation temperature of the Mg–Ti–V–Nb–Cr HEAs decreases obviously with increasing Mg content, which results from the weakened bonding strength of pairs. This study demonstrates that the Mg 6 Ti 24 V 18 Cr 12 HEA is a potential candidate for hydrogen storage. • A series of Mg–Ti–V–Nb–Cr lightweight HEAs for hydrogen storage is designed. • The gravimetric hydrogen storage capacity of Mg6Ti24V18Cr12 is predicated to be as high as 4.091 wt% (H/M = 2). • The dehydrogenation temperature of the Mg–Ti–V–Nb–Cr HEAs decreases with increasing Mg content. [ABSTRACT FROM AUTHOR]

The current work describes how 2D layered materials, such as MoS 2 and WS 2 , might improve the de/re-hydrogenation kinetics of MgH 2. In the presence of WS 2 catalyst, desorption of MgH 2 begins at 277 °C, with a hydrogen storage capacity of 5.95 wt%, while the onset desorption temperature of MgH 2 catalyzed by MoS 2 is 330 °C. In just 1.3 min at 300 °C under 13 atm hydrogen pressure, the MgH 2 -WS 2 absorbed approximately 3.72 wt% of hydrogen, and in 20 min at 300 °C under 1 atm hydrogen pressure, it desorbed around ∼5.57 wt% of hydrogen. To ensure the cyclic stability up to 25 cycles of de/re-hydrogenation of the catalyzed MgH 2 , a continuously 25 cycles of dehydrogenation (under 1 atm hydrogen pressure at 300 °C) and rehydrogenation (under 13 atm hydrogen pressure at 300 °C) were carried out. As a result, MgH 2 -WS 2 exhibits superior cyclic stability than MgH 2 –MoS 2. In addition, with the de/re-hydrogenation kinetics, MgH 2 -WS 2 has a lower reaction activation energy (∼117 kJ/mol) than to other catalyzed and pristine samples. Conversely, the thermodynamical parameters, specifically the change in enthalpy of MgH 2 , are unaffected by addition of these layered WS 2 and MoS 2 catalysts. • The meticulous and precise synthesis of WS 2 and MoS 2 2-D nanomaterials. • The remarkable catalyst of 2-D nanomaterials for the sorption properties of MgH 2. • 2-D WS 2 and MoS 2 are exceptional catalysts in the de- and re-hydrogenation kinetics of MgH 2. • 25 cycles of dehydrogenation and rehydrogenation on WS 2 /MoS 2 -catalyzed MgH 2. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carrier (LOHC) is a hydrogen storage and release technology of growing interest due to its excellent properties. Dibenzyltoluene is one of the best performing organic liquids for this purpose. In this work, we investigate the dehydrogenation reaction of perhydro-dibenzyltoluene (18H-DBT) in a batch reactor using Pt/Al 2 O 3 catalysts. The best catalytic results were obtained at 290 °C with the catalyst featuring lower Pt loading and higher dispersion, achieving a degree of dehydrogenation (DoD) of 88%. After 45 h of catalytic operation, the degree of dehydrogenation dropped by about 35%. The generation of by-products and physical changes in the Pt sites could be potential causes of the observed catalytic degradation. A cleaning treatment was carried out to restore the initial DoD, but only the productivity was improved, leading to a reduction in reaction times. The authors of the paper entitled Activity and degradation of Pt/Al2O3 catalyst assessment in hydrogen release from perhydro-dibenzyltoluene suggests the following highlights: • Hydrogen release increased with increasing temperature. • 0.5 wt % Pt/Al 2 O 3 reported higher catalytic efficiency than 1 wt % Pt/Al 2 O 3. • The catalysts showed a high catalytic efficiency after 45 h of operation. • Cleaning of the catalyst reduced the reaction times. • The generation of by-products and changes in the Pt centres lead to catalytic deactivation. [ABSTRACT FROM AUTHOR]

The carbon steel pipe line of the dehydrogenation tail gas system in a certain styrene unit has a thinning rate of 55.51% and a corrosion rate of up to 5.29 mm/a after one year of use, which restricts the long-term stable operation of the plant. The corrosion of the dehydrogenation tail gas carbon steel pipeline was inspected through electromagnetic eddy current scanning, ultrasonic thickness measurement, and macroscopic inspection. The impact of corrosive medium, process operating parameters, on-site pipeline location and material on pipeline thinning in the dehydrogenation tail gas system was analyzed. The results indicate that the localized corrosion and thinning of the dehydrogenation tail gas carbon steel pipeline are caused by a combination of carbon dioxide corrosion and erosion corrosion under certain temperature and pressure. To alleviate corrosion issues, it is recommended to re-evaluate the process operating conditions of the dehydrogenation tail gas system, add cooling equipment before the dehydrogenation tail gas compressor, or upgrade the pipeline material to 304 austenitic stainless steel. Or consider adding corrosion inhibitors to the dehydrogenation exhaust system. At the same time, regular electromagnetic eddy current scanning or ultrasonic thickness measurement should be carried out to monitor the relevant pipelines and prevent leaks in a timely manner. [ABSTRACT FROM AUTHOR]