Hydrogenation Research Articles

β-Cyclodextrin-Modified Laser-Induced Graphene Electrode for Detection of N6-Methyladenosine in RNA.

Laser-induced graphene (LIG) possesses characteristics of easy handling, miniaturization, and unique electrical properties. We modified the surface of LIG by electropolymerizing β-cyclodextrin (β-CD), which was used to immobilize antibodies on the electrode surface for highly sensitive detection of targets. N6-methyladenosine (m6A) is the most prevalent reversible modification in mammalian messenger RNA and noncoding RNA, influencing the development of various cancers. Here, β-CD was electropolymerized to immobilize the anti-m6A antibody, which subsequently recognized the target m6A. This was integrated into the catalytic hydrogen peroxide-hydroquinone (H2O2-HQ) redox system using phos-tag-biotin to generate electrochemical signals from streptavidin-modified horseradish peroxidase (SA-HRP). Under optimal conditions, the biosensor exhibited a linear range from 0.1 to 100 nM with a minimum detection limit of 96 pM. The method was successfully applied to the recovery analysis of m6A from HeLa cells through spiking experiments and aims to inspire strategies for point-of-care testing (POCT).

CoCe composite catalyst for CO2 hydrogenation: Effect of pore structure

In order to realize the dual carbon goals of “carbon peaking” and “carbon neutrality”, the design and development CO2 hydrogenation catalyst with high performances is of great significance. In this study, the CoCe composite catalysts were prepared by different methods and used to CO2 catalytic hydrogenation. The physicochemical properties of the prepared catalysts were characterized by XRD, BET, TEM/HRTEM, and H2-TPD. The characterization results indicated that the studied CoCe composite catalytsts with different pore structure can be prepared by different preparation methods. The suitable preparation method can promote Co species to be dissolved into the CeO2 lattice to form Ce-O-Co solid solution, which can promote the corresponding Co species to be reduced by H2 to form active Co0 species. The large specific surface area and developed ordered mesoporous structure of the CoCe-HT catalyst precursor, which was prepared by hard-template method, are conducive to the formation of active Co0 species and activation of H2 to produce reactive H species. The CO2 hydrogenation activity of the studied CoCe composite catalysts follows the following order: CoCe-HT > CoCe-CP > CoCe-CA > CoCe-HY. The CoCe-HT catalyst showed high CO2 hydrogenation conversion of 53.9 % and good using stability at 360 °C for 600 min. However, the CoCe-CA prepared by complex method has a poor use stability.

Hydrogenation Reactions with Heterobimetallic Complexes.

Hydrogenations are fundamentally and industrially important reactions that are atom economical paths to synthesize value-added products from feedstock chemicals. The cooperative effects of two or more metal centers in multimetallic active sites is a successful strategy to activate small molecules and facilitate catalytic reactions, and this strategy has been recently applied to catalytic hydrogenation reactions. Furthermore, heterobimetallic complexes have been well-documented to provide novel reaction pathways and improved selectivity, compared to their homo-bimetallic and monometallic analogues. This minireview provides a historical perspective on the development of heterobimetallic catalysts for the hydrogenation of unsaturated substrates and describes recent developments in this burgeoning research area.

Reduction of Trinitrobenzene to Amines with Molecular Hydrogen over Chrysocolla-like Catalysts

The cheap non-noble Cu–SiO2-based nanocatalysts are under intensive study in different reactions resulting in useful chemicals, yet their application in environment protection is poorly studied. In the present work, the influence of the Cu loading (3–15 wt%) on the catalytic behavior of Cu/SiO2 materials was first precisely studied in the hydrogenation of hazardous trinitrobenzene to valuable aromatic amines with molecular hydrogen. The catalysts have been synthesized by the method of deposition–precipitation using urea. The catalyst characterization by XRD, TPR-H2, SEM, TEM, and N2 adsorption methods confirmed that they include nanoparticles of the micro-mesoporous chrysocolla-like phase supported in the mesopores of a commercial SiO2 carrier, as well as revealed formation of the highly dispersed CuO phase in the sample with the highest Cu loading. Variation in reaction conditions showed the optimal ones (170 °C, 1.3 MPa H2) resulting in complete trinitrobenzene conversion with a triaminobenzene yield of 65% for the catalyst with a 15% Cu loading, and the best yield of 82% was obtained over the catalyst with 10% Cu calcined at 600 °C. The results show the potential of Cu phyllosilicate-based catalysts for the utilization of trinitroaromatic compounds via catalytic hydrogenation to amines and their possible applications in a remediation treatment system.

Ligand engineering regulates the electronic structure of Ni-N-C sites to promote electrocatalytic acetylene semi-hydrogenation

Compared with traditional thermal catalytic hydrogenation technology, electrocatalytic acetylene semi-hydrogenation (EASH) is a green and environmentally friendly method. EASH utilizes renewable electricity under normal temperature and pressure conditions, and uses water as a hydrogen source to electrocatalytically semi-hydrogenate acetylene to ethylene. Ni-based single-atom catalysts (SACs) have shown good application prospects in EASH, but there is still much room for optimization. The axial coordination regulation of the active center is a potential means to improve its activity. In this work, the activity and selectivity of NiN4 SACs with 14 axial ligands (X) for EASH were systematically studied via density functional theory (DFT). First, the binding energy and ab initio molecular dynamics simulation results show that all the NiN4-X can exist stably. Second, the Gibbs free energy diagram shows that the activation and adsorption of C2H2 is the rate-determining step of the reaction. The introduction of the –ONO ligand enhances the activation and adsorption of C2H2 by NiN4, which is beneficial to the occurrence of EASH and inhibits the side reactions of hydrogen evolution. The two parameters ΔG∗CHCH and ΔG∗CH2CH3 can be used as characteristic descriptors to predict the activity and selectivity of EASH. Finally, the catalytic activity mechanism was explained from the perspective of electrons and orbitals, and it was found that the dz2 orbital played a leading role in the axial ligand regulation of C2H2 catalytic activity. This work provides a new method for the development of efficient EASH catalysts.

Structure sensitivity in the formic acid-driven catalytic transfer hydrogenation of maleic acid to succinic acid over Pd/C catalysts

A series of carbon-supported palladium catalysts (Pd/C) with average particle size in the range from 3 to 7 nm was prepared by varying the Pd loading. These materials and the influence of their physicochemical properties in the catalytic transfer hydrogenation (CTH) of maleic acid (MAc) to succinic acid (SAc) using formic acid (FAc) as H2 donor were evaluated. The chemical, textural, and surface properties were studied by a number of characterization techniques (ICP-OES, XRD, TEM, and XPS). It was found that the intrinsic rate of SAc formation per surface Pd atom (turn-over frequency, TOF Pdsur) is structure-sensitive. The TOF Pdsur rate increases with the particle size following a volcano-type curve, reaching a maximum for an average particle size of ca. 6 nm. Assuming a cuboctahedral shape with a cubic close-packed structure, an approximation frequently adopted for Pd particles, it was found that, for the series of catalysts, neither the calculated TOF of Pd surface atoms at low coordination sites nor at high coordination are constant. This suggests that no geometric effect is responsible for the structure-sensitivity. Among the different Pd species present in the catalysts (i.e., metallic Pd (Pd0), palladium carbide (PdCx), and oxidized Pd), it was observed that the relative number of surface Pd0 sites also follows a volcano-type curve, which indicates that Pd0 sites are necessarily involved in the most active centers. For particles with an average size larger than 4 nm, the TOF rate of surface Pd0 sites was constant and in the range of 0.12 s−1. For smaller sizes, a more accurate determination of their Pd0 surface concentration is required to obtain reliable surface Pd0 TOF rates.

NiMo-MMO catalyst derived from LDHs precursors toward the deep hydrogenation of pyrene

A series of Ni-based catalysts were prepared via structural topological transformation from the Ni@Al2O3 layered double hydroxides (LDHs) precursors, and applied for the deep catalytic hydrogenation saturation of pyrene in a high-pressure reactor. The pore structures, active species dispersion, surface morphology, amount and type of acid of the prepared catalysts were characterized by BET, XRD, SEM, TEM, XPS, SEM, NH3-TPD and Py-IR. We studied the influence of physicochemical properties of Ni-based catalysts on the regularity and mechanism of deep hydrogenation of pyrene. Meanwhile, the synergy between Ni and Mo, and the interaction between active metals and support were discussed to further reveal the constitutive relationship during the hydrogenation reaction of pyrene. The results of the evaluation of the catalytic hydrogenation of pyrene show that the as-prepared NiMo mixed metal oxide (MMO) catalyst showed excellent catalytic activity: ∼95% pyrene conversion, 90.12% for the selectivity of deep hydrogenation products (hexahydropyrene, decahydropyrene and hexadecahydropyrene). It was expected that the successfully preparation and utilization of NiMo-MMO catalyst could provide a theoretical basis for the design of this kind of catalysts for deep catalytic hydrogenation of polycyclic aromatic hydrocarbons (PAHs).

Microwave-powered integrated carbon capture and utilisation (ICCU) for methane production with rapid temperature response from minimal thermal inertia

Integrated CO2 capture and utilisation (ICCU), emerging as an effective approach for achieving global carbon neutrality goals, demonstrates its potential through the transformation of captured CO2 into valuable methane and the concurrent hydrogen storage via methanation reaction. However, traditional ICCU strategies are heavily reliant on conventional thermal conduction heating, and the in-situ methanation process is constrained by reaction thermodynamics, posing significant challenges. In this study, we introduce for the first time a novel microwave-powered system, employing a clean and efficient energy source that offers rapid heating and on-demand operation and acts as an external field enhancement method in the ICCU-methanation procedure. The designed blend of Ni-loaded CaO and carbon nanotubes (CNTs) integrates the functions of CO2 adsorption, hydrogenation catalysis, and microwave absorbing ability. This novel approach achieved a CO2 capture capacity of 3.31 mmol gDFM-1 with CO2 conversion and CH4 selectivity reaching 71.01 % and 98.17 %, respectively, at a nickel loading of 20 wt%. We also propose a possible rate enhancement mechanism for the microwave-powered ICCU-methanation cyclic process compared to conventional methods. The microwave-powered system can substantially enhance overall efficiency by swiftly responding to temperature swings, thus reducing processing time in ICCU-methanation cycles.

Mo2Ti2C3TX MXene performance in catalytic CO2 hydrogenation and its promotion with single Pt atoms

Mo2Ti2C3Tx MXene materials, bare or loaded with strongly anchored single Pt atoms, were investigated using various methods, including STEM, XPS, XAS and DFT calculations. Upon Pt impregnation, the delaminated Mo-rich MXene surface undergoes partial oxidation, which is reversed by an H2 thermal treatment at 400 °C. The optimized MXene shows high catalytic activity for CO2 hydrogenation to CO and smaller amounts of methane and methanol. Above the pretreatment temperature of 400 °C, the MXene is gradually defunctionalized from O- and F-containing groups and depleted in carbidic carbon, leading to deactivation. Single Pt atoms are cationic after impregnation, and reduce upon H2 treatment, filling surface Mo vacancies. Pt addition increases the MXene activity, in particular by facilitating H2 dissociation, but has little effect on the single-atom catalyst selectivity and on the rate dependence upon reactant partial pressures. The lowest Pt loading leads to the highest turnover frequency, indicating that the MXene surface sites are key to CO2 activation.

Atomically dispersed Ru on flower-like In2O3 to boost CO2 hydrogenation to methanol

Metal-based catalysts are prevalent in the CO2 hydrogenation to methanol owing to their remarkable catalytic activity. Herein, Ru/In2O3 catalysts with different morphologies obtained by doping Ru into In2O3 with irregular, rod-like, and flower-like morphologies are used for catalytic CO2 hydrogenation to methanol. Results indicate that the flower-like Ru/In2O3 (Ru/In2O3-F) exhibits higher catalytic performance than Ru/In2O3 with other morphologies, achieving a 12.9% CO2 conversion, 74.02% methanol selectivity, and 671.36 mgMeOH·h−1·gcat−1 methanol spatiotemporal yield. Furthermore, Ru/In2O3-F maintains its catalytic stability over 200 h at 5 MPa and 290 °C. The promotional effect mainly stems from the fact that electronic structure of Ru can be effectively adjusted by modulating the morphology of In2O3. The strong interaction between atomically dispersed Ru and In2O3-F enhances the structural stability of Ru, inhibiting the agglomeration of the catalyst during the reaction process. Furthermore, density-functional theory calculations reveal that highly dispersed Ru atoms not only perform efficient and rapid electronic gain and loss processes, facilitating the catalytic activation of H2 into H intermediates. It also enables the generated reactive H to rapidly overflow to the surrounding In sites to participate in CO2 reduction. These findings provide a theoretical basis for the development of high-performance catalysts for CO2 hydrogenation.

Alkali‐Mediated/Catalyzed Transition‐Metal‐Free Tandem Reaction Triggered by the Borrowing Hydrogen and Aerobic Dehydrogenation Processes of Alcohols

AbstractThe 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.

Confined synthesis of ultrafine NiCu nanoalloy anchored nanoflower derived from natural attapulgite for efficient catalytic hydrogenation of p-nitrophenol

Improving the performance of catalysts through precise microstructural design is important for their applications. Herein, a series of nanoflower-shaped NiCu nanoalloy/nickel-copper silicate (NiCuSi)/attapulgite (ATP) nanocomposite catalysts was successfully constructed. Initially, the NiCuSi/ATP substrates were prepared using Ni2+ and Cu2+ ions to induce the epitaxial growth of acid-leached ATP. Afterwards, the domain-limited Ni2+ and Cu2+ ions in the silicon framework of NiCuSi were transformed to ultra-small NiCu nanoalloy particles (∼5.71 nm) through an in-situ reduction process. Due to the unique morphology and structure, the catalyst exhibited a specific surface area of up to 227.05 m2/g, which exposed abundant active sites to contact with the reactant molecules. The uniformly dispersed ultra-small NiCu nanoalloys effectively promoted the rapid transfer of interface electrons, resulting in excellent catalytic efficiency of the catalyst. Its catalytic reduction rate for PNP is as high as 0.374 s−1, equivalent to those of the precious metal catalysts, and the excellent catalytic efficiency remains at 98.53 % even after 10 cycles. This study provides a universal and efficient method to develop highly active and stably nanocomposite catalysts from natural and green carries.

Regioselective Encapsulation of Pd Clusters in Hollow Polycrystalline Shell

Zeolite catalysts have been widely applied in petroleum and chemical industries. Nano/hierarchical structure could improve the utilization efficiency of active sites, especially for metal species encapsulated in zeolites. However, the uniformity of zeolite surface and crystallinity would decrease, leading to low stabilization effect. Herein, we developed a seed-directed method to prepare Pd clusters (∼1.3 nm) regioselectively encapsulated in hollow polycrystalline shell of Silicalite-1 zeolite. In nitrobenzene hydrogenation reaction, the optimized Pd@S-1-hp showed a high conversion of 92.2% at 110°C, which is 40% higher than that of Pd clusters in bulk zeolite. Sub-nano Pd species in polycrystalline shell could significantly shorten the diffusion length on the basis of strong microporous confinement effect. Catalytic hydrogenation activity remained stable after six cycles. This structure could be extended to heterogeneous reactions suffering from diffusion limitation.

Regulating electron transfer between valence-variable cuprum and cerium sites within bimetallic metal–organic framework towards enhanced catalytic hydrogenation performance

Modulating the electron distribution between active sites in metal–organic frameworks (MOFs) offers a promising strategy for optimizing their catalytic performance. In this study, we employed a novel heterovalent substitution strategy to synthesize bimetallic organic frameworks (CuxCey-BTC) that feature dual active sites with copper (Cu) and cerium (Ce), Our objective was to achieve efficient hydrogenation of dicyclopentadiene (DCPD) by regulating the electron transfer between the valence-variable Cu and Ce species. The designed CuxCey-BTC were characterized using various spectroscopic and microscopic techniques, along with density functional theory (DFT) calculations, confirming the successful incorporation of bimetallic nodes within the framework structure and the electron transfer between them. The transfer of electrons from the less electronegative Ce to the Cu sites promotes the chemisorption of hydrogen gas (H2) on the electron-rich Cu sites, thereby optimizing the activation of the CC bond in DCPD. The Cu4Ce-BTC catalyst demonstrated exceptional performance, achieving complete conversion of DCPD and significantly surpassing monometallic MOFs. Moreover, we proposed a plausible pathway for the hydrogenation of DCPD. This work highlights the synergistic effects between bimetallic centers and offers a novel strategy to improve the MOFs’ catalytic activity by modulating electron distribution between dual active sites.

Hydrogenation of CO2 to light olefins over Ga2O3-ZIF-8 tandem catalyst

Tandem catalysts composed of metal oxides and zeolites have demonstrated significant potential for the hydrogenation of CO2 to light olefins. However, their development is hindered by the competing reverse water–gas shift reaction and carbon accumulation on the zeolite surface. To address these challenges, we developed a series of innovative tandem catalysts by substituting conventional zeolites with ZIF-8. Our research primarily focused on examining the effects of metal species and content, as well as the particle size of ZIF-8, on catalytic performance. Notably, we achieved a CO2 conversion of 20.2 % and a light olefins selectivity of 73.6 % using a catalyst with 20 % Ga2O3 content and a ZIF-8 particle size of 100 nm at a reaction temperature of 340 °C and pressure of 3.0 MPa. In order to improve the stability of the catalyst, ZIF-8 was modified with La to improve its thermal stability. A CO2 conversion of 23.5 % and a light olefins selectivity of 66.5 % were maintained after 50 h of continuous reaction. While the catalytic activity of La-modified catalysts is slightly lower than that of unmodified ones, their superior stability makes them more suitable for thermal catalytic hydrogenation of CO2. Various characterizations and theoretical calculations revealed that La modification not only enhanced the thermal stability of catalyst but also improved its adsorption and activation capabilities for the reacting gases. Furthermore, the reaction mechanism of CO2 hydrogenation to light olefins was investigated by in-situ diffuse reflectance Fourier transform infrared spectroscopy. This study provides a technical foundation for designing efficient catalysts based on metal–organic frameworks in the field of carbon dioxide thermal catalytic conversion.

Tuning the selectivity of catalytic hydrogenation of fumaric acid with supercritical CO2

The catalytic hydrogenation of fumaric acid, a prominent bioplatform molecule, was evaluated over PdRe/SiO2 within a variety of reaction media compositions comprising methanol, water, supercritical CO2, and their assorted combinations with H2, across a range of temperature and pressure regimes. Meticulous manipulation of the reaction media composition facilitated the precise modulation of catalytic activity to favor specific hydrogenation products. For instance, within a water-saturated supercritical CO2 medium, γ-butyrolactone exhibited a noteworthy 89 % selectivity at 188°C under 250 bar total pressure, whereas in the methanol-containing supercritical CO2 system, hydrogenation displayed a remarkable 91 % selectivity towards tetrahydrofuran at 175°C and 250 bar. This investigation underscores the multifaceted influence of CO2, extending beyond its pressure-derived effects - it functions as a solvent, selectively favoring catalytic pathways and enhancing product selectivity.

Efficient photoreforming of plastic waste using a high-entropy oxide catalyst

Simultaneous catalytic hydrogen (H2) production and plastic waste degradation under light, known as photoreforming, is a novel approach to green fuel production and efficient waste management. Here, we use a high-entropy oxide (HEO), a new family of catalysts with five or more principal cations in their structure, for plastic degradation and H2 production. The HEO shows higher activity than that of P25 TiO2, a benchmark photocatalyst, for the degradation of polyethylene terephthalate (PET) plastics in water. Several valuable products are produced by photoreforming of PET bottles and microplastics including H2, terephthalate, ethylene glycol and formic acid. The high activity is attributed to the diverse existence of several cations in the HEO lattice, lattice defects, and appropriate charge carrier lifetime. These findings suggest that HEOs possess high potential as new catalysts for concurrent plastic waste conversion and clean H2 production.

Synergistic effects in organic mixtures for enhanced catalytic hydrogenation and hydrodeoxygenation

Synergistic effects in organic mixtures for enhanced catalytic hydrogenation and hydrodeoxygenation

Advances in Sustainable γ-Valerolactone (GVL) Production via Catalytic Transfer Hydrogenation of Levulinic Acid and Its Esters

Advances in Sustainable γ-Valerolactone (GVL) Production via Catalytic Transfer Hydrogenation of Levulinic Acid and Its Esters

Strong electronic metal-support interaction of Ni4Mo/N-SrMoO4 promotes alkaline hydrogen electrocatalysis

Ni4Mo electrocatalyst stands out as the promising candidate for hydrogen evolution/oxidation reaction (HER/HOR), yet the intensive hydrogen adsorption leads to sluggish kinetics, decreasing hydrogen catalysis efficiency. Herein, the structure of Ni4Mo nanoparticles anchored on wafer-biscuit-like N-SrMoO4 nanorods (Ni4Mo/N-SrMoO4) is developed to accelerate reaction kinetics by modulating electronic structure. The designed N-SrMoO4 support enables strong electronic metal-support interaction with Ni4Mo, resulting in a downward shift of d-band center and achieving thermally neutral hydrogen adsorption. Ni4Mo/N-SrMoO4 exhibits HER performance with an ultralow overpotential of 15 mV at 10 mA cm−2, superior to Pt/C (η10=18 mV). The outstanding exchange current density of 10.2 mA cm−2 for HOR is three times higher than that of Pt/C (3.5 mA cm−2). Ni4Mo/N-SrMoO4 is further assembled in anion exchange membrane water electrolyzer (AEMWE), resulting in a current density of 100 mA cm−2 at voltage of 1.71 V and the excellent stability of 300 hours. Theoretical calculations and in-situ spectroscopy indicate that the introduction of Sr in N-SrMoO4 effectively enhances electronic metal-support interaction, facilitates the enrichment of adsorbed hydroxyl (OHads) on active sites and weakens hydrogen adsorption on Ni4Mo, thereby accelerating reaction kinetics of hydrogen electrocatalysis.