Selective Hydrogenation Research Articles

Synthesis and properties of palladium catalysts supported on n-modified carbon material sibunit in the reaction of selective hydrogenation of acetylene

The possibility of introducing nitrogen into the structure of the carbon catalyst support Sibunit by high-temperature treatment in a stream of ammonia at 800-1000°C has been studied. It has been shown that preliminary oxidation of the Sibunit surface with a 5% solution of nitric acid promotes more efficient nitrogen binding, which may be due to the presence of surface oxygen-containing groups and/or greater defectiveness of the surface of the oxidized carbon material. The depositing of palladium to Sibunit, subjected to preliminary oxidation and treatment in NH3 at 1000°C, leads to an increase in the activity and selectivity of the Pd/Sibunit catalyst in the hydrogenation of acetylene to ethylene. It was found that the improvement in catalytic characteristics is due to an increase in the availability of supported palladium due to its localization in larger pores of the N-modified support.

Heterogeneous Catalysis of Molecular‐Like Au8M(PPh3)8n+ Clusters Cultivated in Mesoporous SBA‐15

AbstractIt is a dream of researchers to be able to tailor the catalytic performances by adjusting heterogeneous catalysts at the atomic level. Atomically precise metal clusters provide us with the possibility to achieve this challenge. Here, we design a push‐and‐pull synthesis strategy coupled with TiOx coating to prepare the heterogeneous catalysts denoted as TiOx/Au8M@SBA via cultivating atomically precise Au8M(PPh3)8n+ (M=Pd, Pt or Au; n=2 for Pd/Pt and 3 for Au) clusters in mesoporous molecular sieve. The catalysts are made up of the three functional units, which include Au8M(PPh3)8n+ clusters that can act as the active sites, the pore environment of the SBA‐15 that can announce a catalysis show for the clusters with precise number of atoms maintained during the chemical reactions, and the TiOx coating that can further inhibit the migration of the clusters under reaction conditions. The selective hydrogenation of acetylene performed in the fixed‐bed reactor taken, for example, we learn how the atom‐by‐atom tailoring of a heterogeneous catalyst can switch on elusive heterogeneous mechanisms with cluster catalysis. This work sheds light on the fundamental insight into catalysis origin of heterogeneous catalysts and achieves a distinguished level of detail for cluster catalysis.

Heterogeneous Catalysis of Molecular-Like Au8M(PPh3)8 n+ Clusters Cultivated in Mesoporous SBA-15.

It is a dream of researchers to be able to tailor the catalytic performances by adjusting heterogeneous catalysts at the atomic level. Atomically precise metal clusters provide us with the possibility to achieve this challenge. Here, we design a push-and-pull synthesis strategy coupled with TiOx coating to prepare the heterogeneous catalysts denoted as TiOx/Au8M@SBA via cultivating atomically precise Au8M(PPh3)8 n+ (M=Pd, Pt or Au; n=2 for Pd/Pt and 3 for Au) clusters in mesoporous molecular sieve. The catalysts are made up of the three functional units, which include Au8M(PPh3)8 n+ clusters that can act as the active sites, the pore environment of the SBA-15 that can announce a catalysis show for the clusters with precise number of atoms maintained during the chemical reactions, and the TiOx coating that can further inhibit the migration of the clusters under reaction conditions. The selective hydrogenation of acetylene performed in the fixed-bed reactor taken, for example, we learn how the atom-by-atom tailoring of a heterogeneous catalyst can switch on elusive heterogeneous mechanisms with cluster catalysis. This work sheds light on the fundamental insight into catalysis origin of heterogeneous catalysts and achieves a distinguished level of detail for cluster catalysis.

Highly Selective Hydrogenation of Nitriles to Primary Amines without an Additive Using Nanoscale Ni0-NiII/III-bTiO2 Heterojunctions.

Despite significant progress in the catalytic hydrogenation of nitriles, the persistent challenge of requiring additives to prevent condensation byproducts and achieve selectivity toward primary amines demands urgent attention. In this work, we present an integrated approach utilizing a ligand-bridged Ni-Ti bimetallic complex as a precursor to tune Ni0-NiO-NiO(OH) heterojunctions and phases of black titania (bTiO2) by controlling pyrolytic conditions. This tailored phase distribution and charge dynamics across heterojunctions create an effective balance of acidic and basic sites, enabling the direct hydrogenation of nitriles to primary amines without the need for additives. However, at elevated pyrolysis temperatures, this balanced composition begins to shift, with the loss of critical phases that alter the catalyst's structural and chemical properties. This shift reduces amphoteric behavior, resulting in decreased selectivity for primary amines and favoring the formation of condensation byproducts. The catalyst's structure, amphoteric nature, crystallinity, surface area, and active sites are comprehensively characterized using high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), temperature programmed desorption of ammonia (NH3-TPD), temperature programmed desorption of carbon dioxide (CO2-TPD), and CO2 adsorption techniques. The magnetically retrievable catalyst exhibited excellent functional group tolerance, high selectivity, multiple reusability, broad substrate scope, and high activity for nitrile hydrogenation to primary amines, with the potential for advanced catalytic hydrogenation of other functional groups.

Synthesis of Bimetallic Pd/Pt Truncated Nanocubes and Their Catalytic Performance in Selective Hydrogenation of Acetophenone

A series of bimetallic Pd/Pt truncated nanocube catalysts with similar morphologies and particle sizes but different platinum contents were successfully synthesized using a colloidal method without using any capping agents. Their hydrogenation properties were systematically studied and compared with their monometallic Pd or Pt nanocrystal counterparts. The results of EDX-mapping and line scanning show that platinum was relatively uniformly distributed on the surface of the Pd/Pt bimetallic nanocrystals and was not selectively deposited at the corners of the nanocrystals. The results of the selective hydrogenation of acetophenone demonstrate that the hydrogenation rate and the carbonyl selectivity of bimetallic Pd/Pt truncated nanocube catalysts are generally much higher than those of their monometallic Pd or Pt nanocrystal counterparts. It was found that the electronic interaction between palladium and platinum in the bimetallic Pd/Pt truncated nanocube catalysts and the corresponding hydrogenation activity in the selective hydrogenation of acetophenone are closely related to the molar ratio between platinum and palladium and the thickness of the platinum layer in the bimetallic Pd/Pt truncated nanocube catalyst. With an increase in the Pt/Pd molar ratio in the bimetallic Pd/Pt truncated nanocube catalysts, the activity and carbonyl selectivity in the acetophenone hydrogenation reaction increase first, reach a maximum when the molar ratio of Pt/Pd is 0.02 and the theoretical thickness of Pt is 1.3 atomic layers, and then decrease with a further increase in the Pt/Pd ratio. The hydrogenation rate of acetophenone on the Pd/Pt0.02 catalyst reaches 1.07 × 103 mmol·h−1·gcat.−1, which is 79 and 75 times larger than that of the monometallic Pd and Pt nanocrystal catalysts, respectively. The maximum yield of the target product 1-phenylethanol on the Pd/Pt0.02 truncated nanocube catalyst reaches 97.2%, which is 6.6% and 16.7% higher than that of the monometallic Pd and Pt nanocrystal catalysts, respectively.

Effect of Pd/Cu(Co) ratio on catalytic performance of PdCu(Co)/NC bimetallic catalysts for furfural selective hydrogenation.

PdxCuy/NC and PdxCoy/NC with different metal mass ratios of Pd to Cu (or Co) are synthesized. They (Pd : Cu (or Co) = 3 : 7) show excellent catalytic activity and high selectivity to furfuryl alcohol (FA) (or tetrahydrofurfuryl alcohol (THFA)) under quite mild conditions due to synergistic effect of Pd-Cu (Co)-NC.

Evolution characteristics of microwave absorbing carbon material on surface of CoFe2O4@biochar during hydrogen production from methane decomposition process

This study proposes a strategy to convert carbon deposits, generated during the catalytic decomposition of methane for hydrogen production, into high-performance microwave-absorbing materials. This approach not only reduces carbon emissions but also achieves carbon fixation and reuse, promoting environmental sustainability. The research demonstrates that cobalt ferrite (CoFe2O4)-loaded biochar catalysts, at different proportions, exhibit highly efficient and selective hydrogen production capabilities in the process of methane decomposition and hydrogen production, with a peak methane conversion rate as high as 83.6 %, which is higher than that of pure biochar catalysts. The improvement was significant, with an increase of 2.2 times. This catalyst not only strengthens the stability of methane decomposition, but also effectively shortens the reaction induction period, showing excellent catalytic performance and stability. Following methane cracking, an ordered, highly crystalline graphitic carbon structure forms within the catalyst, significantly improving its microwave absorption capacity. At a thickness of 1.3 mm, the catalyst’s microwave absorption reaches a peak value of −41.39 dB, with an effective absorption bandwidth of 4.56 GHz. The catalyst’s outstanding microwave absorption performance arises from synergistic mechanisms, such as multi-layer reflection and interface polarization, which effectively convert electromagnetic energy into thermal energy, facilitating efficient electromagnetic wave dissipation. This research presents an efficient catalyst for the clean utilization of methane resources and explores new pathways to convert industrial by-products into high-value materials, particularly with potential applications in microwave-absorbing technologies.

Selective CO2 hydrogenation to methanol over a novel ternary In-Co-Zr catalyst

To address the challenges of global warming and energy shortages, the technology to convert CO2 into methanol is of great significance Indium-cobalt catalysts have attracted widespread attention due to their significant activity and excellent stability. Herein, In-Co and In-Co-Zr catalyst rich in In2O3 were prepared through a citric acid-assisted co-precipitation method. The results show that the In-Co-Zr catalyst can significantly enhance the activity for hydrogenating CO2 to methanol, achieving a CO2 conversion rate of 17.4 % and a methanol selectivity of 77.7 % under the conditions (5.0 MPa, 310 °C, GHSV = 10.28 l·gcat-1·h-1, H2/CO2 ratio of 4). At a GHSV of 48 l·gcat-1·h-1, the space–time yield of methanol was 0.79 gMeOH·gcat-1·h-1, and the catalyst exhibited stable catalytic activity over a continuous reaction period of 120 h. It was revealed that the incorporation of ZrO2 could significantly improve methanol selectivity of In-Co catalyst. Moreover, an increased oxygen vacancy and strong interaction of the In-Co-Zr catalysts are conducive to improving the CO2 adsorption strength and capacity. It is expected that this novel ternary In-Co-Zr catalyst could inspire new opportunities for designing and developing multi-component hybrid catalysts for highly active, stable and selective CO2 hydrogenation to methanol

Mechanical activation assisted synthesis of atomically dispersed cobalt catalysts supported on N, P co-doped cellulose-derived carbon for nitrobenzene hydrogenation

Modulating the coordination structure of active center atoms of atomically dispersed metal catalysts has emerged as a critical strategy to further enhance the catalytic performance for selective hydrogenation. Herein, we report the successful synthesis of atomically dispersed cobalt catalysts supported on N, P co-doped cellulose-derived carbon (Co1/NPC) via a mechanical activation assisted synthesis method. The introduction of P and N atoms modifies the electronic structure of Co atoms by forming Co–Nx and Co–Px structures, enhancing their ability to dissociate H2 and adsorb nitroarenes, thereby significantly boosting the hydrogenation activity. Consequently, the Co1/NPC catalyst demonstrates outstanding catalytic activity for the selective hydrogenation of nitrobenzene, achieving 99 % conversion and selectivity with a high TOF of 507 h−1, far outperforming the benchmark Co1/NC (TOF of 4 h−1) and CoNPs/NPC catalysts (TOF of 10 h−1). Moreover, Co1/NPC catalysts possess exceptional stability and satisfactory universality. This study provides an efficient and practical catalyst for the production of nitroanilines via the selective hydrogenation of nitroarenes.

Crystal facet engineering of Pd/TiO2 to boost the activity and selectivity for nitroarenes hydrogenation

Crystal facet engineering of Pd/TiO2 to boost the activity and selectivity for nitroarenes hydrogenation

Bucket effect of Cobalt Nanoparticles and Single Atoms in Nitroarenes Transfer Hydrogenation

Synergetic metal nanoparticles (NPs) and single atoms hold significant potential in reactions that require activating multiple substrate molecules. However, due to the differences in adsorption, activation and kinetics among distinct substrates during the multistep reaction process, the synergy and matching relationship between metal NPs and single atoms remain unclear. In this work, we synthesized a series of Co1-NP/CNT@CN-X dual-site catalysts with tunable molar ratios (X%) of Co single atoms to total Co species through a coordination site regulation (CSR) strategy and investigated the bucket effect of the dual active sites in the transfer hydrogenation of nitro compounds. Density functional theory calculations reveal that active hydrogen generation from ammonia borane hydrolysis primarily occurs at the surface of Co NPs, while nitroarenes hydrogenation predominantly takes place at Co single atoms, which is consistent with experimental findings. The optimized Co1-NP/CNT@CN-7.6 maintains high selectivity for nitro hydrogenation (> 99.9%) and exhibits conversion (99.9%) nearly 3.7 times that of the original Co1-NP/CNT@CN-1.6 catalyst (27%), achieved by overcoming the bucket effect between Co NPs and single atoms. This work not only elucidates the synergistic mechanisms of dual sites in transfer hydrogenation, but also establishes that optimizing matching effect is an effective approach to significantly enhance their catalytic performance.

Electronic regulation of Ru electrocatalyst for enhanced atomic hydrogen generation and selective chlorophenol hydrogenation

Electronic regulation of Ru electrocatalyst for enhanced atomic hydrogen generation and selective chlorophenol hydrogenation

Waste lithium-ion batteries for selective transfer hydrogenation of bio-based ethyl levulinate: Experiments, kinetics and economic assessment

The present research firstly developed the waste lithium-ion batteries as heterogenous catalysts for catalytic upgrading of bio-based ethyl levulinate (EL) into γ-valerolactone (GVL) using 2-propanol as both the hydrogen source and solvent. The existing acid and basic sites in waste lithium-ion batteries significantly favored the MPV reduction of bio-based EL, wherein 87.4 % GVL yield and low activation energy of 35.2 kJ/mol were achieved. Furthermore, the waste lithium-ion batteries contributed to H-transfer upgrading of a variety of building blocks containing unsaturated groups, such as aldehydes and esters. More gratifyingly, the economic assessment demonstrated that EL-to-GVL transformation via H-transfer manner was preferred as compared with the traditional hydrogenation, in which the total cost for converting 1 kg EL declined by 10.58 $ and overall profit increased by 12.35 $. In addition, the plausible mechanism for H-transfer upgrading of EL into GVL over waste lithium-ion batteries was proposed.

Selective Hydrogenation of Furfural into Cyclopentanone Over Composite Metal Catalysts under Mild Conditions

Background/Introduction: The direct hydrogenate conversion of furfural to cyclopentanone is very interesting technology in biomass conversion and utilization. Many kinds of metal catalysts were used in this field, and composite metal catalysts exhibited superior catalytic performance. The hydrogenation process and rearrangement of the furan ring are competitive, polymerization of furfural can prevent the improvement of yield for the main product. Objective: Efficient and high selective catalyst need to be prepared for the improvement the yield of cyclopentanone from hydrogenate conversion of furfural under mild conditions. Methods: Preparation of many composite metal catalysts and catalytic test for the direct hydrogenate conversion of furfural to cyclopentanone. Characterization is chosen to explore the strong metal synergistic effect and micro react mechanism. Results: MCM-41 was chosen as the carrier, and both WO3 and TiO2 were selected as the modifiable assistant, Ru-Cu-WO3@TiO2-MCM-41 were prepared successfully and performed a strong metal synergistic effect in this reaction. The 2%Ru-5%Cu-4%WO3@TiO2-MCM-41 exhibited a 98.54% yield of cyclopentanone when water was chosen as solvent and good stability was found in the recycle tests in mild conditions. Conclusion: A certain amount of WO3 is helpful to enhance the Ru and Cu atoms’ dispersion and the number of acidic sites on the surface of nano catalyst, which may weaken the cracking of C-C bonds and improved the yield of cyclopentanone in mild conditions. A certain amount of TiO2- anatase species adjusted the textural properties of the carrier and show good synergism catalytic function. The best catalytic hydrogenation conversion of furfural was high at 99.75%, and the best selectivity to cyclopentanone was high at 98.79% over 2%Ru-5%Cu-4%WO3@TiO2-MCM-41 catalyst under mild conditions.

Preparation of Pd nanoparticles modified hollow TiO2 dodecahedrons for highly selective hydrogen detection

Preparation of Pd nanoparticles modified hollow TiO2 dodecahedrons for highly selective hydrogen detection

Matrimid®/LaNi5 mixed matrix membranes for selective hydrogen separation from industrial waste gas streams

This study reports the synthesis, characterization, and evaluation of Matrimid®/LaNi5 mixed matrix membranes for selective hydrogen separation from industrial waste gas streams. Through a combination of experimental investigation and modelling, hydrogen absorption in LaNi5 intermetallic compounds and its impact on separation performance were explored. It was observed that the composite membranes exhibit significant enhancement in hydrogen permeation compared to pristine Matrimid® membranes. The results showed that Matrimid®/LaNi5 membranes deliver 5 times higher H2 permeability (107 Barrer) and higher selectivity (H2/CO2: 14.5, H2/N2: 83.5, H2/CH4: 78.5 and H2/CO: 84.5). Furthermore, hydrogen permeation flux modelling in Matrimid®/LaNi5 elucidated the contribution of each transport mechanism with high regression coefficients (> 0.92) and within ± 15% error. Moreover, the results demonstrate the capability of Matrimid®/LaNi5 membranes to surpass Robeson upper bound for H2/CO2 while it is almost reached for H2/N2 and H2/CH4 separations, highlighting the potential of these new membranes for industrial-scale applications.

Computational screening of single-cluster catalysts anchored on g-C3N4 for nitroreduction of 3-nitro-1,2,4-trizole-5-one (NTO)

3-nitro-1,2,4-triazole-5-one (NTO) is widely used as an insensitive explosive in high-safety weapon systems; however, it poses significant environmental risks due to its high solubility and anionic nature. Despite 3-amino-1,2,4-triazole-5-one (ATO) has been identified as the key intermediate during NTO degradation, developing highly active and selective catalysts for the NTO to ATO process remains challenging. Using computational screening with density functional theory (DFT), ab initio molecular dynamics (AIMD) simulations, and enhanced sampling approach, this study presents a rational design among metal trimer (M3, where M = Ag, Au, Cu, Ir, Os, Pt, Pd, Rh, and Ru) cluster anchored on N-vacancy and perfect graphitic carbon nitride (g-C3N4) as robust single-cluster catalysts (SCCs) with promising efficiency for NTO nitroreduction. Through a three-step process involving structural optimization, AIMD simulation, and enhanced sampling calculation, we found that Ru shows remarkable activity and selectivity for NTO nitroreduction, particularly in a solvent environment with a higher concentration of H. Notably, the Ru3@1CN SCC demonstrates the ability to directly reduce NTO to ATO in the first two steps. This work opens new avenues for NTO nitroreduction in contamination control and production of functionalized chemicals, providing valuable guidance for selective hydrogenation of other nitro compounds as well.

Engineering Metal-MOF Interfaces for Selective CO2 Hydrogenation to Methanol.

The hydrogenation of CO2 to methanol is a promising pathway toward sustainable fuel production and carbon recycling. A key factor in the efficiency of this process lies in the interaction between the metal catalyst and its support. Metal-Organic Frameworks (MOFs) have emerged as highly effective platforms due to their tunable structures, large surface areas, and ability to form stable interfaces with single-atom metals or metal nanoparticles. These metal-MOF interfaces are crucial for stabilizing active sites, preventing sintering, and enhancing catalytic performance. In this concept paper, we explore the role of these interfaces in promoting CO2 hydrogenation, focusing on Cu-Zn, Cu-Zr, and Zn-Zr interfaces. The formation of strong interactions between metal sites and MOF nodes enables precise control over the dispersion and electronic environment of the active species, significantly improving methanol selectivity and long-term stability. By analyzing recent advancements in MOF-supported catalysts, this work highlights the concept of engineered metal-MOF interfaces to drive the development of next-generation catalysts for efficient methanol synthesis from CO2.

Co@Pd–Co Core–Shell Nanoparticles as Catalysts for the Selective Hydrogenation of Furfural to Furfuryl Alcohol

Co@Pd–Co Core–Shell Nanoparticles as Catalysts for the Selective Hydrogenation of Furfural to Furfuryl Alcohol

Optimization of Ru/ZSM-5 catalyst for selective d-glucose hydrogenation to sorbitol: A box-behnken design approach

The hydrogenation of D-glucose to sorbitol holds significant importance in biomass biorefineries. With a focus on enhancing the efficiency and selectivity of this reaction, this research investigated various optimization parameters (catalyst dosage, reaction time, and temperature) over 0.5 %Ru/ZSM-5 prepared via impregnation method. The optimization process was carried out using Box-Behnken design (BBD). The results showed accurate predictive equations for all reaction responses, with R2 values exceeding 97 % and no significant errors observed. Additionally, the 2D contour plot revealed the relationship between time and temperature, highlighting that a long reaction time and high temperature could lead to reduced sorbitol yield due to the formation of by-products. Under the optimal catalyst dosage of 0.6 g, reaction time of 100 min, and temperature of 120°C, the D-glucose conversion and sorbitol yield were 99.6 ± 0.35 % and 99.43 ± 0.45 %, respectively. NMR results confirmed the exclusive production of sorbitol under these optimal conditions. Furthermore, the study demonstrated that the catalyst could be reused at least seven times without a significant decrease in D-glucose conversion or sorbitol yield, while ICP-OES analysis confirmed no Ru leaching during the reaction. Therefore, this research provides a biomass valorization strategy by optimizing the production process of sorbitol via D-glucose hydrogenation.