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The catalytic hydrogenation of biomass-derived chemicals is essential in chemical industry due to the growing demand for sustainable and renewable energy sources. In this study, we present a comprehensive theoretical investigation regarding the hydrogenation of glycolaldehyde to ethylene glycol over a Ru/C catalyst by employing density functional theory and ab initio molecular dynamics simulations. With inclusion of explicit solvation, we have demonstrated that the glycolaldehyde hydrogenation is significantly improved due to the fast proton transfer through the hydrogen bond network. The enhanced activity could be attributed to the participation of the solvent water as the hydrogen source and the highly positively charged state of a Ru cluster in an aqueous phase, which are critical for the activation of aldehyde groups and proton-assisted hydrogenation. Overall, our findings provide valuable insights into glycolaldehyde hydrogenation over Ru/C catalysts in the aqueous phase, highlighting the importance of solvation effects in the biomass conversion. [ABSTRACT FROM AUTHOR]

We present a series of borane‐tethered cyclic (alkyl)(amino)carbene (cAAC)‐copper complexes, including a borane‐capped Cu(I) hydride. This hydride is unusually hydridic and reacts rapidly with both CO2 and 2,6‐dimethylphenol at room temperature. Its reactivity is distinct from variants without a tethered borane, and the underlying principles governing the enhanced hydricity were evaluated experimentally and theoretically. These stoichiometric results were extended to catalytic CO2 hydrogenation, and the borane‐tethered (intramolecular) system exhibits ~3‐fold enhancement relative to an intermolecular system. [ABSTRACT FROM AUTHOR]

The selective hydrogenation of biomass derivatives presents a promising pathway for the production of high‐value chemicals and fuels, thereby reducing reliance on traditional petrochemical industries. Recent strides in catalyst nanostructure engineering, achieved through tailored support properties, have significantly enhanced the hydrogenation performance in biomass upgrading. A comprehensive understanding of biomass selective upgrading reactions and the current advancement in supported catalysts is crucial for guiding future processes in renewable biomass. This review aims to summarize the development of supported nanocatalysts for the selective hydrogenation of the US DOE′s biomass platform compounds derivatives into valuable upgraded molecules. The discussion includes an exploration of the reaction mechanisms and conditions in catalytic transfer hydrogenation (CTH) and high‐pressure hydrogenation. By thoroughly examining the tailoring of supports, such as metal oxide catalysts and porous materials, in nano‐supported catalysts, we elucidate the promoting role of nanostructure engineering in biomass hydrogenation. This endeavor seeks to establish a robust theoretical foundation for the fabrication of highly efficient catalysts. Furthermore, the review proposes prospects in the field of biomass utilization and address application bottlenecks and industrial challenges associated with the large‐scale utilization of biomass. [ABSTRACT FROM AUTHOR]

ABSTRACT The syntheses and bioevaluation of 3‐acyl‐2‐pyridones have garnered significant interest in recent years as a novel class of compounds with diverse biological activities. The bioactivities cover a wide range of therapeutic areas including antimicrobial, antitumor, anti‐inflammatory, antifungal, antibiotic, neuritogenic, cytotoxic, and antiviral activities. Therefore, 3‐acyl‐2‐pyridone scaffold offers a versatile platform for the development of new molecules with potential applications in medicinal chemistry. The recent exploration on synthesis and bioevaluation of 3‐acyl‐2‐pyridones has yielded promising results, making them attractive targets for further optimization and development of new therapeutic agents. This review summarizes the available information on total synthesis of 3‐acyl‐2‐pyridone containing natural products, and the other synthetic strategies developed for accessing the 3‐acyl pyridones such as multicomponent synthesis, condensation reaction, microwave‐assisted synthesis, catalytic hydrogenation reactions, metalation reaction, Michael addition, and formylation reactions. The presented information may serve as a valuable resource for researchers working in the field of medicinal chemistry and drug discovery, stimulating further exploration and development of this intriguing scaffold. [ABSTRACT FROM AUTHOR]

The catalytic hydrogenation of CO2 to formate was achieved using the previously reported dichloro(η6‐p‐cymene){diphenyl(3‐methyl‐2‐indolyl)phosphine}ruthenium (1) as a catalyst under mild conditions. In this complex, the phosphorus‐based ligand adopts a κ1‐P coordination mode. The catalytic activity was achieved in the presence of DBU as a base providing a TONmax value of 3,800. In order to explore potential transformations occurring within the catalytic reactions, a series of stoichiometric tests were performed. Complex 1 was reacted with DBU to form chloro(η6‐p‐cymene){diphenyl(3‐methyl‐2‐indolide)phosphine}ruthenium (2). Structural characterization of complex 2 confirmed a κ2‐P,N coordination mode for the ligand resulting in a four membered metallacycle. Reaction of 2 with H2 led to the formation of hydrochloro(η6‐p‐cymene){diphenyl(3‐methyl‐indolyl)phosphine}ruthenium (3), albeit not with a clean conversion. This is the product resulting from the formal addition of hydrogen across the Ru−N bond of the metallacycle. Complex 3 was also synthesized via an alternative route involving the reaction of complex 1 with Me2NH • BH3 as a means of converting Ru−Cl to Ru−H [ABSTRACT FROM AUTHOR]

The utilization of liquid organic hydrogen carrier (LOHC) based on acetophenone has been considered a promising approach for high energy density hydrogen storage, but its industrial application is limited by the low reaction and mass transfer rates observed in conventional reactors. Microreactors have the potential to promote hydrogen storage technology, and, in this study, we propose a tubular reactor coupled with a gas/liquid microdispersion module. Via generating microbubbles prior to the flow of gas and liquid reactants in the tubular reactor, our designed reactor facilitates enhanced gas/liquid interaction mass transfer, thereby improving hydrogenation reaction characteristics. To evaluate the performance of this intensified trickle bed reactor, we investigated the hydrogenation of acetophenone (AP) to 1-phenylethanolis. The results demonstrate that compared to traditional trickle bed reactors, the designed hydrogenation reactor exhibits superior performance under pressures below 2 MPa, with an absence of byproducts, increased conversion and selectivity of AP, and an achieved hydrogen storage rate reaching 0.095 mol H 2 / g Pd / min. [Display omitted] • An intensified hydrogenation reactor was proposed for efficient hydrogen storage. • A gas/liquid micro-dispersion system has been incorporated into a tubular reactor. • The reaction performance of reactors is evaluated using acetophenone hydrogenation. • The intensified reactor shows a nearly twofold increase in hydrogen storage rate. [ABSTRACT FROM AUTHOR]

The MoS2 nanosheets are acquired via a facile hydrothermal strategy, and the M/MoS2 (M = Pt, Rh, Pd, Ru) samples are gained by impregnation. By comparing the catalytic behaviors of these catalysts for p-nitroacetophenone selective hydrogenation, it is found that the catalytic property and selectivity for one −NO2 group hydrogenation of Ru/MoS2 outperform those of other as-prepared catalysts. In addition, the Ru/MoS2 catalysts with various Ru contents (0.37, 0.88, or 2.45 wt %) are used for 3-nitrostyrene selective hydrogenation, and the results show that 0.88 wt % Ru/MoS2 displays the highest catalytic activity (turnover frequency) of TOF = 118.4 h–1 (TOF = 64.2 h–1 for 0.37 wt %Ru/MoS2 and TOF = 61.7 h–1 for 2.45 wt %Ru/MoS2) under the reaction conditions of 100 °C, 3.0 MPa H2, and 1 h. The nanostructure characterization of the as-prepared catalysts (XRD, XPS, TEM, HRTEM, H2-TPD, XAS, AC-STEM, AC-STEM-EDX elemental mapping, and line scanning) demonstrate that Ruδ+ single atoms and Ru clusters are well dispersed on the support. Moreover, 0.88 wt % Ru/MoS2 exhibits extremely high selectivity of one −NO2 group hydrogenation (∼100%) at high conversion for other selected nitroaromatics' hydrogenation, such as nitrobenzene, 2-chloronitrobenzene, 1,3-dinitrobenzene, 3-nitrostyrene, p-nitroacetophenone, and p-nitrobenzonitrile. This is mainly due to the fact that Ru is present with single atoms and clusters, producing the synergism of Ruδ+ single atoms, Ru clusters, and MoS2 nanosheets. And the synergism mechanism is given below: hydrogen is preferentially adsorbed and activated at Ru clusters (forming activated H* species), the −NO2 group is easily adsorbed and activated at Ruδ+ single atoms (charge interaction between electrons from O in −NO2 and positive charge from Ruδ+ single atoms), and H* transfers to Ruδ+ single atoms by the hydrogen spillover effect of the MoS2 nanosheets, reacting with the −NO2 group, forming desired aromatic amines. [ABSTRACT FROM AUTHOR]

The functionalization of silica supports with isonicotinamide (NIC) facilitated the stabilization of small (3.5 nm), spherical cobalt nanoparticles (CoNPs) used in catalytic hydrogenation. Various silica matrices, including amorphous, mesoporous, and non‐porous ones, were synthesized and post‐grafted with NIC to serve as ligands for stabilizing CoNPs. Comprehensive characterization techniques were employed to fully analyze the prepared materials, which were then utilized in the catalytic hydrogenation of acetophenone, serving as a benchmark reaction to assess the impact of different silica supports on catalysis. The porosity and surface nature of the silica matrices played crucial roles in anchoring the amide ligand, and the presence of the ligand was essential for stabilizing the nanoparticles. Among the catalysts tested, CoNPs@SBA‐15/NIC exhibited the highest catalytic activity and demonstrated excellent performance in the hydrogenation of alkenes, nitriles, ketones, and quinoline under relatively mild conditions. No significant alteration in catalyst morphology or leaching of metal was observed after the reaction. Notably, this catalytic system achieved turnover numbers comparable to those of homogeneous cobalt catalysts. Additionally, one‐pot tandem reductive amination reactions starting from aldehydes and involving both amines and nitrobenzene yielded secondary and tertiary amines in good yields, highlighting the robustness and versatility of the catalyst. [ABSTRACT FROM AUTHOR]

cis,cis-Muconic acid (MA) is a bio-based chemical that can be converted to direct replacement chemicals or performance-advantaged bioproducts. We recently engineered the bacterium Pseudomonas putida KT2440 for the co-utilization of glucose and xylose to produce MA. This study evaluates the effect of additional genetic modifications, media composition, and bioprocess strategy on MA titer, productivity, and yield in bioreactor cultivations. We achieve a MA titer of 47.2 g L−1, a productivity of 0.49 g L−1 h−1, and a yield of 0.50 C-mol C-mol−1 from glucose and xylose supplemented with 5% (v/v) corn steep liquor with a P. putida strain harboring the deletion of gacS. Additionally, we demonstrate efficient MA production from corn stover-derived sugars and scalability to 150 L bioreactors. Techno-economic analysis and life cycle assessment predict that adipic acid, derived from catalytic hydrogenation of MA, can achieve a selling price as low as $2.60 per kg, approaching cost parity and reducing greenhouse gas emissions by up to 80% relative to fossil carbon-based adipic acid. [ABSTRACT FROM AUTHOR]

Ni-W catalysts find extensive application in catalysis; however, the impact of diverse morphologies on their catalytic activity remains a relatively unexplored area. Using hydrothermal/solvothermal synthesis methods, we successfully synthesized Ni-W catalysts with various morphologies, including sheet-like, sphere-like, rod-like, flower-like, and particulate-like structures. Comprehensive investigations into the influence of morphology on the catalytic activity of these Ni-W catalysts were conducted, employing techniques such as SEM, XRD, XPS, TG-DTG, BET, H2-TPR, and H2-TPD. Remarkably, the flower-like Ni-W catalyst displayed exceptional catalytic properties in ethylbenzene hydrogenation, exhibiting not only high hydrogenation activity but also superior sulfur resistance. Consequently, the flower-like Ni-W catalyst holds great potential for applications in industrial catalysis. [ABSTRACT FROM AUTHOR]

α-Hydroxy-benzylphosphonates obtained by the Pudovik reaction of substituted benzaldehydes and dialkyl phosphites were added to the triple bond of dialkyl acetylenedicarboxylates. Optimum conditions involved a 24 hours stirring in the presence of 10% diazabicycloundecene in dichloromethane to afford the adducts as a mixture of predominant E - and a minor Z -isomers in 75–90% yields after flash chromatography. The structures of the geometrical isomers were confirmed by NOE- and ROE-measurements. Catalytic hydrogenation of the olefinic moiety of the adducts led to the diastereoisomers of corresponding saturated derivatives. [ABSTRACT FROM AUTHOR]

The hydrogenation of magnesite to CH 4 and MgO offers a powerful approach for CO 2 direct utilization. To deepen the understanding of the reaction mechanisms, (Mg 5 (CO 3) 4 (OH) 2 (H 2 O) 4 was selected as a model compound to gain insights into carbonate hydrogenation. A novel Ni/Fe/ZrO 2 catalyst with ferromagnetic properties was employed to facilitate the magnetic separation of the catalyst from the solid products. Thermodynamic simulation and experiments were conducted to address key issues such as gas evolution during catalytic hydrogenation, the effects of catalyst on CH 4 selectivity, and the separation of solid products and catalyst. The results indicate that lower temperatures favor CH 4 formation, whereas higher temperatures favor CO formation. Increasing Ni loading can enhance the CH 4 selectivity. With the presence of 10Ni/Fe/ZrO 2 catalyst, 100% CH 4 selectivity can be achieved at 300 °C. Moreover, 10Ni/Fe/ZrO 2 catalyst exhibits high magnetic responsiveness, facilitating the solid separation and the recycle of the catalyst. • A novel route for the hydrogenation of magnesite to produce CH 4 and MgO is proposed. • A ferromagnetic Ni/Fe/ZrO 2 catalyst enables efficient separation of the catalyst and product. • Low temperature favors CH 4 formation, while high temperature favors CO formation. • 100% CH 4 selectivity can be achieved at 300 °C with the presence of 10Ni/Fe/ZrO 2. [ABSTRACT FROM AUTHOR]

Catalytic transfer hydrogenation of levulinic acid (LA) to γ‐valerolactone (GVL) was attractive in biomass conversions since GVL is highly useful in different applications, such as polymer synthesis, fuel, and food. Various catalytic systems were reported for the reaction, yet harsh reaction conditions were generally required, which could restrict the scaling up of the reaction. Herein, we developed an effective and green bi‐solvent system of isopropanol/water for the catalytic transfer hydrogenation of LA to GVL over a ruthenium–phosphorous carbon (Ru‐PC) catalyst. It was found that the presence of water in the solvent system promoted the production of GVL from LA. The effect of isopropanol/water ratios and other reaction conditions were investigated, exhibiting that 93.8% yield of GVL was achieved using isopropanol/water ratio of 2.5:2.5 at 140 °C for 4 h and over Ru‐PC catalyst. Combining water and organic solvent not only reduced the usage of organic solvent but also created an effective bi‐solvent system for catalytic reactions. [ABSTRACT FROM AUTHOR]

Frustrated Lewis pairs (FLPs), composed of spatially hindered Lewis acids and bases, are promising catalysts for the catalytic hydrogenation of unsaturated organic substrates, but the lack of reusability limits their development. The functionalization of solid materials with molecular FLP is a promising method for preparing heterogeneous FLP catalysts. In this work, a magnetically recyclable FLP catalyst was successfully prepared for the reductive carbonyl compounds to the corresponding alcohols. FLP of 2‐Ph2PPhCHO/B(C6F5)3 was grafted into NH2‐MIL‐101@Fe3O4 composite material through an aldehyde‐amine condensation reaction. The as‐prepared FLP‐NH‐MIL‐101@Fe3O4 exhibited remarkable catalytic activity for aldehyde/ketone carbonyl compounds. In addition, FLP‐NH‐MIL‐101@Fe3O4 displays outstanding magnetic recyclability and can be reused 8 times without loss of activity. [ABSTRACT FROM AUTHOR]

While supported metal nanoparticles (NPs) have shown significant promise in heterogeneous catalysis, precise control over their interaction with the support, which profoundly impacts their catalytic performance, remains a significant challenge. In this study, Pt NPs are incorporated into thioether‐functionalized covalent organic frameworks (denoted COF‐Sx), enabling precise control over the size and electronic state of Pt NPs by adjusting the thioether density dangling on the COF pore walls. Notably, the resulting Pt@COF‐Sx demonstrate exceptional selectivity (> 99 %) in catalytic hydrogenation of p‐chloronitrobenzene to p‐chloroaniline, in sharp contrast to the poor selectivity of Pt NPs embedded in thioether‐free COFs. Furthermore, the conversion over Pt@COF‐Sx exhibits a volcano‐type curve as the thioether density increases, due to the corresponding change of accessible Pt sites. This work provides an effective approach to regulating the catalysis of metal NPs via their microenvironment modulation, with the aid of rational design and precise tailoring of support structure. [ABSTRACT FROM AUTHOR]

The development of base metal catalysts capable of CO2 hydrogenation is a challenge and a necessity to progress from the scarce noble metal catalysts. In this regard, we report herein the first non-phosphine-based Ni complex, supported by a "carbazolato-bis-NHC" pincer ligand framework, for efficient catalytic hydrogenation of CO2 to formate. A tailored combination of the Ni complex as a catalyst, DBU as a base, and Zn(OAc)2 as an additive offered enhanced activity leading to a TON up to 5476 and an excellent yield up to 92% for the formate product from a reaction on ∼27 mmol scale. [ABSTRACT FROM AUTHOR]

The catalytic hydrogenation of carbon dioxide to formate is of great interest due to its significant role in CO2 utilization. In this study, a novel heterogeneous Ru(III) catalyst was prepared by immobilizing RuCl3 on a porous organic polymer (POP) obtained from 1,4-phthalaldehyde (PTA) and 4,4'-biphenyldicarboxaldehyde (BPDA) with melamine. A copolymerization strategy utilizing monomers of varying lengths was employed to prepare the POP-supported Ru catalyst with adjustable porosity. The optimization of the framework porosity resulted in enhanced CO2 affinity, accelerated mass transfer, and a remarkable enhancement in catalytic activity. A high turnover number (TON) of 2458 was achieved for the CO2 hydrogenation to formate in 2 h with catalyst Cat-3 under 3 MPa (CO2/H2 = 1: 1) at 120 °C in 1 M Et3N aqueous solution. Moreover, the Cat-3 demonstrated good recyclability and was able to be reused for five consecutive runs, resulting in a high total TON of 9971. [ABSTRACT FROM AUTHOR]

The development of base metal catalysts capable of CO2 hydrogenation is a challenge and a necessity to progress from the scarce noble metal catalysts. In this regard, we report herein the first non-phosphine-based Ni complex, supported by a "carbazolato-bis-NHC" pincer ligand framework, for efficient catalytic hydrogenation of CO2 to formate. A tailored combination of the Ni complex as a catalyst, DBU as a base, and Zn(OAc)2 as an additive offered enhanced activity leading to a TON up to 5476 and an excellent yield up to 92% for the formate product from a reaction on ∼27 mmol scale. [ABSTRACT FROM AUTHOR]

Phosphine‐ligated transition metal complexes play a pivotal role in modern catalysis, but our understanding of the impact of ligand counts on the catalysis performance of the metal center is limited. Here we report the synthesis of a low‐coordinate mono(phosphine)‐Rh catalyst on a metal‐organic layer (MOL), P‐MOL • Rh, and its applications in the hydrogenation of mono‐, di‐, and tri‐substituted alkenes as well as aryl nitriles with turnover numbers (TONs) of up to 390000. Mechanistic investigations and density functional theory calculations revealed the lowering of reaction energy barriers by the low steric hindrance of site‐isolated mono(phosphine)‐Rh sites on the MOL to provide superior catalytic activity over homogeneous Rh catalysts. The MOL also prevents catalyst deactivation to enable recycle and reuse of P‐MOL • Rh in catalytic hydrogenation reactions. [ABSTRACT FROM AUTHOR]

A full selectivity control over the catalytic hydrogenation of nitroaromatics leads to the production of six possible products, i.e., nitroso, hydroxylamine, azoxy, azo, hydrazo or aniline compounds, which has however not been achieved in the field of heterogeneous catalysis. Currently, there is no sufficient evidence to support that the catalytic hydrogenation of nitroaromatics with the use of heterogeneous metal catalysts would follow the Haber's mechanistic scheme based on electrochemical reduction. We now demonstrate in this work that it is possible to fully control the catalytic hydrogenation of nitroaromatics into their all six products using a single catalytic system under various conditions. Employing SnO2‐supported Pt nanoparticles facilitated by the surface coordination of ethylenediamine and vanadium species enabled this unprecedented selectivity control. Through systematic investigation into the controlled production of all products and their chemical reactivities, we have constructed a detailed reaction network for the catalytic hydrogenation of nitroaromatics. Crucially, using oxygen‐isolated characterization techniques is essential for identifying unstable compounds such as nitroso, hydroxylamine, hydrazo compounds. The insights gained from this research offer invaluable guidance for selectively transforming nitroaromatics into a wide array of functional N‐containing compounds, both advancing fundamental understanding and fostering practical applications in various fields. [ABSTRACT FROM AUTHOR]

Catalytic hydrogenation of CO2 to value-added fuels and chemicals is of great importance to carbon neutrality but suffers from an activity-selectivity trade-off, leading to limited catalytic performance. Herein, the ZnFeAlO4 + SAPO-34 composite catalyst was designed, which can simultaneously achieve a CO2 conversion of 42%, a CO selectivity of 50%, and a C2-C4= selectivity of 83%, resulting in a C2-C4= yield of almost 18%. This superior catalytic performance was found to be from the presence of unconventional electron-deficient tetrahedral Fe sites and electron-enriched octahedral Zn sites in the ZnFeAlO4 spinel, which were active for the CO2 deoxygenation to CO via the reverse water gas shift reaction, and CO hydrogenation to CH3OH, respectively, leading to a route for CO2 hydrogenation to C2-C4=, where the kinetics of CO2 activation can be improved, the mass transfer of CO hydrogenation can be minimized, and the C2-C4= selectivity can be enhanced via modifying the acid density of SAPO-34. Moreover, the spinel structure of ZnFeAlO4 possessed a strong ability to stabilize the active Fe and Zn sites even at elevated temperatures, resulting in long-term stability of over 450 h for this process, exhibiting great potential for large-scale applications. [ABSTRACT FROM AUTHOR]

Innovative cobalt and nickel catalytic materials containing metal nanoparticles immobilized into the inner tubes of pristine halloysite, a naturally occurring nanoclay, and their application in hydrogenation reactions of a large variety of substrates from biomass and industrial wastes are described herein. The catalytic materials with a high metal loading (>24 wt %) were prepared by a one-pot two-step procedure in the absence of additional stabilizers, leading to metal nanoparticles essentially confined into the support lumen (constituted of aggregates of small nanoparticles) as a result of the privileged electrostatic interactions between aluminols and metal acetate salts [Ni-(OAc)2 and Co-(OAc)2]. Both catalytic materials, Ni/Hal and Co/Hal, gave different chemoselectivities toward the reduction of unsaturated functional groups (carbonyl, CC, and nitrile) under solvent-free conditions, thus affording selectively value-added compounds depending on the nature of the metal. In particular, the squalene hydrogenation monitoring permitted identification of the partial hydrogenated products and estimation of the partial turnover numbers and frequencies, achieving a cumulative TON of 110 and TOF of 151 h–1 using the most active catalytic system, i.e., Ni/Hal. [ABSTRACT FROM AUTHOR]

A new hydroxo‐bridged ruthenium (II) complex [{Ru(η6‐p‐cymene)(iPr2P−O)}2(μ‐OH)]Cl (2) has fortuitously been isolated from the reaction between the known ruthenium(II) complex [RuCl2(η6‐p‐cymene)(iPr2P‐OH)] (1) in either CDCl3 or CHCl3 solutions in the presence of excess DBU (1,8‐diazabicyclo(5.4.0)undec‐7‐ene) at room temperature. Complex 2 is only formed under specific conditions as an orange‐colored air and moisture stable binuclear complex. It is formed via the deprotonation of the P−OH unit in [RuCl2(η6‐p‐cymene)(iPr2P‐OH)]. Complex 2 has been fully characterized by spectroscopic and analytical methods. Its structure was determined by single crystal X‐ray diffraction which reveals a boat‐shaped motif containing a bridging hydroxide unit which undergoes hydrogen bonding with a chloride counterion. Complex 2 was utilized as a catalyst for the hydrogenation of CO2 to formic acid salt using molecular hydrogen. The catalytic reactions were performed at 100 °C in THF in the presence of DBU as a base to isolate [DBU+H][OC(O)H] salt as the final product. Using catalyst loadings down to 0.01 mol%, it was possible to hydrogenate gaseous CO2 with TONs up to 9900. [ABSTRACT FROM AUTHOR]

Harnessing CO2 in conjunction with inexpensive reusable H2 for catalytic hydrogenation is a viable method for lowering the environmental impact of industrial operations while producing useful chemicals and fuels. To make the process more sustainable, particular emphasis was paid to the heterogeneous catalyst system in this regard. Intending to profit from both homogeneous and heterogeneous catalysis in real‐world circumstances for the CO2 hydrogenation reaction, heterogenized molecular catalysts are receiving a lot of attention among heterogeneous catalysts. This review is devoted to significant developments in single‐site heterogenized molecular catalysts for CO2 hydrogenation reactions. Attempting to illustrate the state‐of‐the‐art developments in this domain, the present work meticulously summarizes several recently reported heterogenized molecular catalysts for the CO2 hydrogenation process producing formic acid/formate, N‐formamide, and methanol. The fundamental structure–activity relationships and mechanistic understanding are given particular attention since they offer solid foundations for sensible catalyst architectural design. Important variables that influence catalytic activity are also emphasized, such as electron density, metal dispersion, porous nature, surface area, a robust backbone, and coordination environment of metal sites. Finally, a short assessment is given as potential directions for further research. [ABSTRACT FROM AUTHOR]

Supported metal single atom catalysis is a dynamic research area in catalysis science combining the advantages of homogeneous and heterogeneous catalysis. Understanding the interactions between metal single atoms and the support constitutes a challenge facing the development of such catalysts, since these interactions are essential in optimizing the catalytic performance. For conventional carbon supports, two types of surfaces can contribute to single atom stabilization: the basal planes and the prismatic surface; both of which can be decorated by defects and surface oxygen groups. To date, most studies on carbon‐supported single atom catalysts focused on nitrogen‐doped carbons, which, unlike classic carbon materials, have a fairly well‐defined chemical environment. Herein we report the synthesis, characterization and modeling of rhodium single atom catalysts supported on carbon materials presenting distinct concentrations of surface oxygen groups and basal/prismatic surface area. The influence of these parameters on the speciation of the Rh species, their coordination and ultimately on their catalytic performance in hydrogenation and hydroformylation reactions is analyzed. The results obtained show that catalysis itself is an interesting tool for the fine characterization of these materials, for which the detection of small quantities of metal clusters remains a challenge, even when combining several cutting‐edge analytical methods. [ABSTRACT FROM AUTHOR]

A new hydroxo‐bridged ruthenium (II) complex [{Ru(η6‐p‐cymene)(iPr2P−O)}2(μ‐OH)]Cl (2) has fortuitously been isolated from the reaction between the known ruthenium(II) complex [RuCl2(η6‐p‐cymene)(iPr2P‐OH)] (1) in either CDCl3 or CHCl3 solutions in the presence of excess DBU (1,8‐diazabicyclo(5.4.0)undec‐7‐ene) at room temperature. Complex 2 is only formed under specific conditions as an orange‐colored air and moisture stable binuclear complex. It is formed via the deprotonation of the P−OH unit in [RuCl2(η6‐p‐cymene)(iPr2P‐OH)]. Complex 2 has been fully characterized by spectroscopic and analytical methods. Its structure was determined by single crystal X‐ray diffraction which reveals a boat‐shaped motif containing a bridging hydroxide unit which undergoes hydrogen bonding with a chloride counterion. Complex 2 was utilized as a catalyst for the hydrogenation of CO2 to formic acid salt using molecular hydrogen. The catalytic reactions were performed at 100 °C in THF in the presence of DBU as a base to isolate [DBU+H][OC(O)H] salt as the final product. Using catalyst loadings down to 0.01 mol%, it was possible to hydrogenate gaseous CO2 with TONs up to 9900. [ABSTRACT FROM AUTHOR]

The paramount concerns of global warming, fossil fuel depletion, and energy crises have prompted the need of hydrocarbons productions via CO2 conversion. In order to achieve global carbon neutrality, much attention needs to be diverted towards CO2 management. Catalytic hydrogenation of CO2 is an exciting opportunity to curb the increasing CO2 and produce value‐added products. However, the comprehensive understanding of CO2 hydrogenation is still a matter of discussion due to its complex reaction mechanism and involvement of various species. This review comprehensively discusses three processes: reverse water gas shift (RWGS) reaction, modified Fischer Tropsch synthesis (MFTS), and methanol‐mediated route (MeOH) for CO2 hydrogenation to hydrocarbons. Along with analysing the reaction pathways, it is also very important to understand the real‐time evolvement of catalytic process and reaction intermediates by employing in‐situ characterization techniques under actual reaction conditions. Subsequently, in second part of this review, we provided a systematic analysis of advancements in in‐situ techniques aimed to monitor the evolution of catalysts during CO2 reduction process. The section also highlights the key components of in‐situ cells, their working principles, and applications in identifying reaction mechanisms for CO2 hydrogenation. Finally, by reviewing respective achievements in the field, we identify key gaps and present some future directions for CO2 hydrogenation and in‐situ studies. [ABSTRACT FROM AUTHOR]

The catalytic hydrogenation of the toxic and harmful p-chloronitrobenzene to produce the value-added p-chloroaniline is an essential reaction for the sustainable chemical industry. Nevertheless, ensuring satisfactory control of its chemoselectivity is a great challenge. In this work, a N/S co-doped metal-free carbon catalyst has been fabricated by using cysteine as a source of C, N, and S. The presence of calcium citrate (porogen agent) in the mixture subjected to pyrolysis provided the carbon with porosity, which permitted us to overcome the issues associated with the loss of heteroatoms during an otherwise necessary activation thermal treatment. Full characterization was carried out and the catalytic performance of the metal-free carbon material was tested in the hydrogenation reaction of p-chloronitrobenzene to selectively produce p-chloroaniline. Full selectivity was obtained but conversion was highly dependent on the introduction of S due to the synergetic effect of S and N heteroatoms. The N/S co-doped carbon (CYSCIT) exhibits a mesoporous architecture which favors mass transfer and a higher doping level, with more exposed N and S doping atoms which act as catalytic sites for the hydrogenation of p-chloronitrobenzene, resulting in enhanced catalytic performance when compared to the N-doped carbon obtained from melamine and calcium citrate (MELCIT) used as a reference. [ABSTRACT FROM AUTHOR]

The development of biodegradable materials from biomass is a crucial strategy for leveraging biomass resources. A key component in this process is 2,5-bis(hydroxymethyl)furan (BHMF), a significant biomass-derived platform chemical. However, producing BHMF with high selectivity through the selective hydrogenation of 5-hydroxymethylfurfural, while avoiding the creation of unwanted byproducts, is a complex challenge. In our research, we have developed a novel catalyst featuring a magnetic core. This catalyst, which consists of platinum loaded onto a graphene-like shell, has been applied to the catalytic hydrogenation of HMF in an aqueous environment. Under the optimized conditions of 373 K, 3 MPa H2, and 1 h reaction time, a BHMF yield exceeding 99% was achieved. This method presents a promising and effective approach for the high-value conversion of biomass waste into polymer materials and pharmaceutical chemicals. [ABSTRACT FROM AUTHOR]

.Reductive C−N bond generation strategies of nitroarenes to form N‐arylformamide and azole derivatives were developed under the influences of magnetically separable Pd@rGO‐CuFe2O4 nanoparticle‐catalyzed reaction conditions. These reactions proceed at a very low catalyst loading in H2O as the solvent, which leads to a higher percentage of yields (up to 96 %) of the products. The catalyst is recovered from the reaction medium by using an external magnet and recycled for four consecutive reaction cycles with a less amounts of leaching. [ABSTRACT FROM AUTHOR]

Highly dispersed Pd/N-doped carbon dots (Pd/NCDs) were successfully immobilized in the mesoporous channels of amino-functionalized dendritic mesoporous silica nanospheres (NMS). The synthesized Pd/NCDs@NMS catalyst exhibits outstanding performance in the catalytic reduction of 4-nitrophenol (4-NP), achieving a turnover frequency of 1461.8 mol·molPd−1·h−1, with the conversion rate remaining above 80% after 11 cycles. Experiments and density functional theory calculations reveal that the NCDs significantly affect the electronic structure of Pd nanoparticles, leading to changes in the energy barriers for the adsorption of 4-NP at the Pd sites and the conversion of 4-NP reaction intermediates, which is a key factor contributing to the catalytic performance. This study offers a new strategy for synthesizing carbon-dot-modified metal-based catalysts. [ABSTRACT FROM AUTHOR]

Development of efficient and stable non‐noble metal catalysts applied to the catalytic transfer hydrogenation of nitroarenes under mild conditions is still challenging. Herein, we report magnetically recyclable catalysts prepared via simple two‐stage pyrolysis of Co‐MOF‐74 and melamine composites. The optimized catalyst Co@C/CNTs‐10‐700 shows excellent conversion and selectivity towards transfer hydrogenation of nitroarenes with different hydrogen donors. Its excellent stability against formic acid corrosion makes it can be used in a wide range. The excellent catalytic performance can be ascribed to the synergistic effect between carbon nanotubes and Co nanoparticles. Furthermore, the catalyst was easily recycled owing to its magnetism and reused up to ten consecutive cycles without significant loss of activity, indicating that the excellent catalytic stability holds great promise in fields of industrial application. [ABSTRACT FROM AUTHOR]

Hydrogenation of CO2 to olefin catalyzed by iron‐based catalysts is a sustainable and important way to achieve carbon neutrality. In this study, iron‐based catalysts were facilely prepared by direct pyrolysis of ferric fumarate (FF), which are applied to CO2 hydrogenation to olefin reaction to explore the effects of pyrolysis temperature and atmosphere on catalytic performance of the catalysts. Among them, NaFe‐Air‐400 catalyst exhibits the highest catalytic activity with 33.7 %, and light olefin selectivity reaches as high as 47.1 %. The catalytic performance of pyrolytic catalysts is better than that the impregnated NaFe catalyst on activated carbon (NaFe/AC). A series of XRD, Raman and SEM characterization results show a suitable pyrolysis temperature would promote the balance between amorphous carbon and graphene, which can affect the formation of FexCy phase, leading the distinctive activity and olefin selectivity. Hence, the presented one‐step pyrolysis methodology would provide a facile and quick synthesis of highly‐active iron‐based catalyst design for CO2 conversion. [ABSTRACT FROM AUTHOR]

Herein, a series of Cu, Ni catalysts were synthesized using mesoporous SiO2 (MCM‐41) and fumed SiO2 as supports for the catalytic hydrogenation of furfural (FF). The MCM‐41 support facilitated the high dispersion of Cu, Ni nanoparticles (NPs), and the hydrogenation products are primarily in the form of alcohols. For fumed SiO2, the proper amounts of acid sites contributed to the better selectivity of 2‐methyltetrahydrofuran(2‐MTHF). Hydrogenation results showed that the 10Cu10Ni/MCM‐41 catalyst afforded a 93.6 % yield of tetrahydrofurfuryl alcohol (THFA), while the 10Cu10Ni/SiO2 catalyst afforded a 61.73 % yield of 2‐MTHF and a 31.63 % yield of THFA. Meanwhile, it is also found that impregnating nickel salt before copper salt is more likely to promote the formation of deep hydrogenation products. Cyclic experiments indicate that developing a one‐step hydrogenation process with selective production of fully hydrogenated products is still a daunting and challenging task. [ABSTRACT FROM AUTHOR]

Heterogeneous CO2 hydrogenation catalytic reactions, as the strategies for CO2 emission reduction and green carbon resource recycling, play important roles in alleviating global warming and energy shortages. Among these strategies, photothermal CO2 hydrogenation technology has become one of the hot catalytic technologies by virtue of the synergistic advantages of thermal catalysis and photocatalysis. And it has attracted more and more researchers' attentions. Various kinds of effective photothermal catalysts have been gradually discovered, and nickel-based catalysts have been widely studied for their advantages of low cost, high catalytic activity, abundant reserves and thermal stability. In this review, the applications of nickel-based catalysts in photothermal CO2 hydrogenation are summarized. Finally, through a good understanding of the above applications, future modification strategies and design directions of nickel-based catalysts for improving their photothermal CO2 hydrogenation activities are proposed. [ABSTRACT FROM AUTHOR]

γ-valerolactone (GVL), derived from biomass, is a crucial platform compound for biofuel synthesis and various industrial applications. Current methods for synthesizing GVL involve expensive catalysts and high-pressure hydrogen, prompting the search for greener alternatives. This study focuses on a novel zirconium phosphate (ZrP)-pillared zeolite MCM-36 derivative catalyst for converting levulinic acid (LA) to GVL using alcohol as a hydrogen source. The incorporation of ZrP significantly contributes to mesoporosity and greatly enhances the acidity of the catalysts. Additionally, we employed 31P MAS NMR to comprehensively investigate the influence of phosphorus species on both the acidity and the catalytic conversion of LA to GVL. By adjusting the Zr-to-P ratios, we synthesized catalysts with enhanced acidity, achieving high conversion of LA and selectivity for GVL. The catalyst exhibited high recyclability, showing only minor deactivation over the course of five cycles. Furthermore, the catalyst was successfully applied to the one-pot conversion of furfural to GVL, showcasing its versatility in biomass conversion. This study highlights the potential of the MCM-ZrP1 catalyst for sustainable biomass conversion and offers insights for future research in renewable energy technologies. [ABSTRACT FROM AUTHOR]

Catalytic hydrogenation of carbon dioxide (CO2) for the preparation of higher carboxylic acids is attractive and promising. Herein, we demonstrate a general strategy for producing higher carboxylic acids via reaction of CO2 and H2 with light (C2~C4) oxygenates such as ketones, alcohols, polyols, ethers and epoxides. In a green solvent consisting of ionic liquid (1‐ethyl‐3‐methylimidazolium iodide) and water, the reaction can be efficiently accelerated by RhI3 catalyst and I2 promoter at 170 °C. Very high or remarkable yields of higher carboxylic acids were synthesized via C−C bond formation between the intermediates generated from the oxygenates and CO2. Detailed study indicated that the catalyst and the solvent had excellent synergistic effect for promoting the reaction. The strategy can effectively convert the bulk and inexpensive feedstocks to value‐added carboxylic acids, and therefore is promising for commercial application. [ABSTRACT FROM AUTHOR]

Catalytic hydrogenation of carbon dioxide (CO2) for the preparation of higher carboxylic acids is attractive and promising. Herein, we demonstrate a general strategy for producing higher carboxylic acids via reaction of CO2 and H2 with light (C2~C4) oxygenates such as ketones, alcohols, polyols, ethers and epoxides. In a green solvent consisting of ionic liquid (1‐ethyl‐3‐methylimidazolium iodide) and water, the reaction can be efficiently accelerated by RhI3 catalyst and I2 promoter at 170 °C. Very high or remarkable yields of higher carboxylic acids were synthesized via C−C bond formation between the intermediates generated from the oxygenates and CO2. Detailed study indicated that the catalyst and the solvent had excellent synergistic effect for promoting the reaction. The strategy can effectively convert the bulk and inexpensive feedstocks to value‐added carboxylic acids, and therefore is promising for commercial application. [ABSTRACT FROM AUTHOR]

Cyclopropanes are among the most important structural units in natural products, pharmaceuticals, and agrochemicals. Herein, we report a manganese-catalyzed cyclopropanation of allylic alcohols with sulfones as carbene alternative precursors via a borrowing hydrogen strategy under mild conditions. Various allylic alcohols and arylmethyl trifluoromethyl sulfones work efficiently in this borrowing hydrogen transformation and thereby deliver the corresponding cyclopropylmethanol products in 58% to 99% yields. Importantly, a major benefit of this transformation is that the versatile free alcohol moiety is retained in the resultant products, which can undergo a wide range of downstream transformations to provide access to a series of functional molecules. Mechanistic studies support a sequential reaction mechanism that involves catalytic dehydrogenation, Michael addition, cyclization, and catalytic hydrogenation. Developing readily available and bench-stable reagents for the cyclopropanation of olefins is needed as traditional methodologies mainly rely on carbene-based strategies. Herein, the authors report a manganese-catalyzed cyclopropanation of allylic alcohols with sulfones via a borrowing hydrogen strategy under mild conditions. [ABSTRACT FROM AUTHOR]

A silica supported FeCoNiCuRu high-entropy alloy (HEA) nanoparticle catalyst was prepared using a simple organic ligand chelate assisted thermal-reduction method. The organic ligand tannin is utilized to chelate Fe, Co, Ni, Cu, and Ru, facilitating the formation of HEAs with a homogeneous distribution of metal elements. The FeCoNiCuRu HEA nanoparticles are uniformly dispersed on the silica with an average size of approximately 17 nm. The formation of the HEA significantly enhances electron transfer among the individual metals within the silica supported FeCoNiCuRu catalysts. The silica supported FeCoNiCuRu HEA nanoparticle catalysts demonstrate superior hydrogenation performance for selective hydrogenation of 5-hydroxymethylfurfural, in comparison to both silica supported monometallic catalysts and their mixture. This simple organic ligand chelate assisted thermal-reduction method provides a universal strategy for generating HEA catalysts with uniform dispersion for a wide range of catalysis applications. [ABSTRACT FROM AUTHOR]

Rising levels of carbon dioxide (CO 2) emissions due to human activities exert a substantial adverse effect on the environment. The conversion of CO 2 into methanol (CH 3 OH) through hydrogenation is a promising way to utilize this greenhouse gas, thus maintaining carbon in the cycle. In terms of sustainability, methanol is of particular interest because of its dual utilization potential as a fuel or base material to produce different chemicals. The versatility of the latter allows it to be used directly as a precursor to produce numerous compounds, including dimethyl ether (DME), olefins, formaldehydes, and hydrocarbon fuels. This paper first reviews the latest developments in catalyst design, focusing on the relationship between catalyst structure and performance. In addition, recent advances in understanding the reaction mechanisms, optimizing catalyst architectures, innovating membrane reactors, and reaction conditions have been discussed. This summarizes the strategies for increasing the efficiency of sustainable methanol production with the help of membranes. This study provides an outlook for future research in this field. [Display omitted] • Developing efficient hydrogen conversion is essential for addressing climate change. • Technological improvements in the synthesis of water selective zeolite membranes. • Latest developments in CO 2 hydrogenation using Cu-based catalysts. • Adapting zeolite membranes in catalytic membrane reactors to increase methanol yield. • Challenges and perspectives of CO 2 hydrogenation in the presence of a membrane. [ABSTRACT FROM AUTHOR]

Pd/C catalysts play a pivotal role in contemporary chemical industries due to their exceptional performance in diverse hydrogenation processes and organic reactions. Over the past century, researchers have extensively explored the factors influencing Pd/C catalyst performance, particularly emphasizing the impact of oxygen-containing groups through oxidation or reduction modifications. However, most studies use respective Pd/C catalysts to analyze the catalytic reactions of one or a class of chemical bonds (polar or non-polar). This study investigates alterations in Pd/C catalysts during temperature-programmed reduction (TPR) and evaluates the hydrogenation activity of unsaturated polar bonds (C=O, acetophenone) and non-polar bonds (C≡C, phenylacetylene) in Pd/C catalysts. The experimental results indicate that the reduction of Pd/C decreases the content of oxygen-containing groups, reducing hydrogenation activity for acetophenone but increasing it for phenylacetylene. This research highlights the preference of regular Pd surfaces for non-polar bond reactions and the role of Pd/oxide sites in facilitating polar bond hydrogenation. These discoveries offer essential insights into how oxygen-containing groups influence catalytic performance and allow us to propose potential avenues for enhancing the design and production of Pd/C catalysis. [ABSTRACT FROM AUTHOR]

Organometallic ruthenium complexes with p-cymene = 1-methyl-4-(1-methylethyl)-benzene and N^N = bidentate polypyridyl ligands constitute interesting candidates with biological and catalytic properties. Towards this aim, we have synthesized four ruthenium(II)–arene complexes of the type [Ru(η6-p-cymene)(N^N)Cl][X] (N^N = Br-Qpy = 6-bromo-4-phenyl-2-pyridin-2-yl-quinoline, X = Cl− (1a); PF6− (1b); N^N = OH-Ph-Qpy = 4-(4-phenyl-2-(pyridin-2-yl)quinolin-6-yl)phenol, X = Cl− (2a); PF6− (2b)). This is the first report of ruthenium(II) p-cymene complexes incorporating substituted pyridine–quinoline ligands, with –Br and –C6H4OH groups in the 6-position of quinoline. We also refer to the cytotoxicity of the ligands and their possible effect of modulating the activity of the ruthenium(II) complexes. These were characterized by a combination of spectroscopic methods (ATR-IR, UV–Vis, multinuclear NMR), elemental analysis, and conductivity measurements. The solid-state structure of 2b, determined by single-crystal X-ray diffraction, reveals a three-legged piano-stool geometry. The in vitro cytotoxic activities of the new complexes were evaluated in HEK293T (human embryonic kidney cells) and in HeLa cells (cervical cancer cells), via the MTT assay. Poor in vitro anticancer activities were observed for the HeLa cancer cell line, with 2a being the most potent (IC50 = 75 μΜ). The cytotoxicity of Br-Qpy in HEK293T is comparable to that of cisplatin. Both complexes 1a and 1b successfully catalyze the transfer hydrogenation of benzophenone to benzhydrol by 2-propanol at 82 °C. The catalytic performance of 1a in the ratio of S:Cat:B = 400:1:40 (S = substrate, Cat = catalyst, B = base = KOiPr) leads to a conversion of 94%, within 3 h of reaction. Presumably, catalytic transformation takes place via ruthenium(II) hydride species being the active catalyst. [ABSTRACT FROM AUTHOR]

Porous carbon supported metal catalyst with embedded structure has witnessed the success in enhancing catalyst stability; however, the development of a simple yet efficient strategy to fabricate catalyst with controllable embedding degree is still a great challenge. Herein, we report a facile impregnation-coating-pyrolysis (ICP) strategy to fabricate ultrafine Ru nanoparticles embedded into N-doped porous carbon nanosheets (Ru@CN). Both the dispersion and exposure degree of Ru nanoparticles in Ru@CN catalyst could be efficient controlled through regulating the coating time of carbon precursors. As expected, the obtained Ru@CN catalyst exhibited an acid resistance for the hydrogenation of levulinic acid in an aqueous phase. Specifically, the spent Ru@CN catalyst shows a significant enhancement in catalytic activity compared with fresh one because the fact that part of Ru active sites confined inside carbon support could be liberated during the reaction process. We anticipate that this ICP strategy may provide a new approach to fabricate the embedded catalyst with high hydrothermal stability. [ABSTRACT FROM AUTHOR]

Palladium (Pd)-based catalysts are widely used for CO2 hydrogenation reactions due to the capability to activate H2, which enhances the overall CO2 conversion. However, most of the current Pd catalysts reported show high CO2 conversion only at higher temperature, and the exploration of efficient catalyst enabling low temperature conversion (180–300 °C) is of importance. In this study, a series of Pd-B/ZnAl2O4 catalysts were synthesized via in-situ doping, resulting in the Pd crystal transformation induced from crystal to amorphous. The catalytic hydrogenation activity of the amorphous Pd-B catalyst reaches its zenith at a Pd-B mole ratio of 1:2, accompanied by the superior catalysis stability in CO2 hydrogenation. Various characterization techniques, including XRD, CO-DRIFTS, H2-TPR, XPS and TEM, were used to investigate the properties of the Pd-B/ZnAl2O4 catalyst. The results showed that the Pd-B/ZnAl2O4 catalyst exhibited higher dispersion and better CO2 conversion efficiency compared to unmodified Pd catalyst. Additionally, the methanol space–time yields are nearly doubled when the B decoration is employed. At 280 °C, CO2 conversion was improved and methanol selectivity remained at ~ 65%. This study provides valuable insights into the design and optimization of Pd-B based catalysts for CO2 hydrogenation at low temperatures. [ABSTRACT FROM AUTHOR]

In this paper, an efficient and green CuMgA catalyst was prepared with the co-precipitation method. The geometric structure and electronic properties of the catalyst was analyzed by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR) and Fourier infrared spectroscopy (FI-IR). It was found that Cu nanoparticles in the catalyst had uniform dispersion with a suitable Cu0 to Cu+ ratio. Also, the calcination temperature had a significant effect on the composition and structure of the Cu-based catalyst, and the prepared CuMgAl catalyst could be calcinated at 723 K to obtain particles with small size and highly dispersed Cu+ and Cu0 species. In addition, Catalytic hydrogenation of dimethyl 1,4-cyclohexane dicarboxylate (DMCD) was carried out with a high-pressure reactor using a CuMgAl catalyst. Surprisingly, under mild conditions with an initial hydrogen pressure of 2.8 Mpa, the conversion of DMCD was up to 100%, and the product selectivity of 1,4-cyclohexane dimethanol can reach 91.6%, which meaning important guiding significance for further industrial applications to achieve a more efficient and environmentally friendly production process. [ABSTRACT FROM AUTHOR]

Agricultural residue is an important biomass resource in China. Utilization of agricultural residue for production of high-quality fuel oil is an attractive and challenging topic towards the goals of “Carbon Peaking and Carbon Neutrality”. Biomass hydropyrolysis integrated with volatile catalytic hydrogenation is a new process that can efficiently improve the yield and quality of bio-oil. This work is purposed to explore this new biomass conversion technology by laboratory experiments using a tandem pressurized fixed bed reactor. A bimetallic molecular sieve catalyst (NiMo-HZSM-5) was prepared by an impregnation method and used for catalytic hydrogenation. Biomass was hydropyrolyzed under a condition of 5 MPa H2 pressure, 15℃/min heating rate and 700℃ final temperature to generate volatile matter, which was online hydrogenated through the NiMo-HZSM-5 catalyst bed under a condition of 5 MPa H2 pressure, 320℃ reaction temperature and 26 s residence time (corresponding to space velocity of 112.5 h−1 ). The paper firstly presents the oil production results of three types of agricultural residue, corn stalk, cotton stalk and peanut straw by the catalytic hydrogenetion. The paper is then devoted to further clarifying the conversion characteristics of different biomass fiber constituents by means of the water washing and acid washing pretreatments of three agricultural residues as well as by adopting cellulose and lignin as model compounds. Results showed that in the case of non-catalytic hydrogenation, all of the bio-oils obtained from three agricultural residues contained oxygenates and aromatic hydrocarbons as two main classes of compounds, and that from peanut straw also contained a high proportion of nitrogenous compounds. In contrast, all of the bio-oils derived from three agricultural residues by the catalytic hydrogenation (CH bio-oils) contained almost neither oxygenates nor nitrogenous compounds. The yields of CH bio-oils reached 10.3%–15.9% for three agricultural residues. The CH-bio-oils were composed of 73.0–84.8% saturated aliphatic hydrocarbons (mainly cyclopentanes, cyclohexanes, and perhydro- naphthalenes), 6.1%–13.1% partially hydrogenated aromatic hydrocarbons (mainly di-, tetra-hydronaphthalenes) and a small amount of monocyclic aromatic hydrocarbons. The result highlights that the two-stage process of hydrogenation pyrolysis integrated with NiMo-HZSM-5 catalytic hydrogenation can effectively convert agricultural residue into a kind of high-quality bio-oil composed mainly of alicyclic hydrocarbons. The water washing could remove about half of neutral extractives from each of three agricultural resides. After the water washing, three agricultural residues showed increases in the yields of CH bio-oil to 18.1%–18.5%, suggesting that neutral extractives are less conducive to the production of CH bio-oil compared to other fiber components. The acid washing enabled cellulose and lignin to be left in the agricultural residues as main components. Via this pretreatment, the yields of CH bio-oil increased to 18.2%–22.5% for three agricultural residues, with cotton stalk having the highest yield. The yields of typical aliphatic hydrocarbon compounds (methyl-cyclopentane, methyl-cyclohexane and decahydro-naphthalene) from all three agricultural residues were increased by the acid washing. The study using model compounds revealed that cellulose is a fiber for not only achieving a high yield of CH bio-oil but also selectively producing aliphatic hydrocarbon compounds such as cyclopentane, cyclohexane, and decahydro-naphthalene. Meanwhile, lignin has a lower yield of bio-oil, and it tends to produce monocyclic aromatic hydrocarbons. Lignin can also generate cyclohexane compounds and partially hydrogenated polycyclic aromatic hydrocarbons, but it has a low propensity to the formation of cyclopentane compounds. This study has provided a new technical route to utilizing agricultural residues for high-efficient production of fuel oil. [ABSTRACT FROM AUTHOR]

Catalytic hydrogenation of carbon dioxide (CO2) to higher alcohols is one of the important ways to realize the high value utilization of CO2 and mitigate the greenhouse effect. The research progress on catalytic hydrogenation of CO2 to higher alcohols in recent years was reviewed. Firstly, the favorable reaction conditions and catalyst requirements for catalytic hydrogenation of CO2 to higher alcohols were analyzed from the thermodynamic point of view. Then the researches of different types of catalysts (precious metal based, copper based, cobalt and molybdenum based catalysts) applicable to the field were introduced. Finally, based on the key intermediates and main reaction pathways, the synthesis mechanisms of catalytic hydrogenation of CO2 to higher alcohols were summarized. Through summary and analysis, the main challenges in the research of catalytic hydrogenation of CO2 to higher alcohols were pointed out, and the future research direction in the field was prospected. [ABSTRACT FROM AUTHOR]

The extensive use of fossil energy leads to wanton emission of CO2 and serious environmental problems. The exploration of high‐performance catalysts plays a pivotal role in CO2 resource utilization. In this paper, CuCeyK catalysts are prepared by wet impregnation method using ordered mesoporous SiO2 as support for the reverse water gas shift (RWGS) reaction. The physicochemical properties of the prepared catalysts are characterized by H2‐TPR, BET, XRD, Quasi in‐situ XPS, H2‐TPD, and CO2‐TPD techniques. The results demonstrate thatthe Cu0 species can form synergistic effects with oxygen vacancies (Ov) to enhance the CuCeyK catalytic performance. Additionally, the electronic effects between Ce and Cu not only enhances the adsorption and activation performances of the catalyst towards CO2 and H2 molecules, but also effectively suppresses the sintering of Cu0 species, thereby enhancing the stability of the corresponding catalyst. It is worth mentioning that the Ce content also directly affects the catalytic performances of the CuCeyK catalyst. The CuCe15K catalyst with a Ce content of 15% displays excellent CO2 hydrogenation performances, and the CO2 conversion and CO selectivity up to 41 % and 100 % at 420 °C, respectively. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Incorporating metal nanoparticles (MNPs) in metal–organic frameworks (MOFs) demonstrated great potential in the field of photo‐/photothermal‐catalysis. However, the oriented design and optimization of the 3D nano‐architectures of MOF substrates to achieve high‐efficiency light harvesting remains a challenge. Herein, guided on theoretical simulation, a facile etching strategy was employed to fabricate a 3D orderly‐stacked‐MOF‐nanosheet‐structure (CASFZU‐1) with a high electric field energy‐density‐distribution; well‐dispersed MNPs were afterwards encapsulated onto the MOF support. The unique nanosheet structure improved the light absorbance over the broadband spectrum, thereby enhancing the plasmonic photothermal effects of the MNPs@CASFZU‐1 composites. Based on the plasmon‐driven photothermal conversion, the MNPs@CASFZU‐1 composites exhibited approximately twofold catalytic efficiency in the hydrogenation reaction and a lower temperature for the full conversion of carbon monoxide, compared to their bulk‐type composites. The surface‐plasmon‐driven photothermal effects can be exploited in innovative MNPs@MOF platforms for various applications. [ABSTRACT FROM AUTHOR]