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With the rapid development of modern society, the consumption of fossil fuels during the industrial production process produces a significant amount of carcinogens. Converting the highly toxic biphenyl (BP) to the valuable product cyclohexylbenzene (CHB) can decrease the emission of carcinogenic aromatic hydrocarbons. In this study, we prepared a series of 20%Ni/SiO2 catalysts with different specific surface areas (SSAs) using the over-volume impregnation method, as well as 20%M/SiO2 (M = Fe, Cu, Co, and Ni) catalysts to highlight the effects of support SSAs and active metal on the performance of BP selective hydrogenation to CHB. The catalysts were characterized by XRD, N2 physisorption, TEM, and H2-TPR, which demonstrated that a high SSA would be helpful for the dispersion of the active metal. The evaluation results revealed that 20%Ni/SiO2-300 exhibited excellent activity and stability in the selective hydrogenation of BP to CHB (BP conversion: 99.6%, CHB yield: 99.3% at the conditions of 200 °C, 3 MPa, 4 h and isopropanol as the solvent) among the catalysts with different SSAs, which was also superior to the performance over the catalysts with other transition metals as the active sites. The structure–activity relationship of the employed catalysts for the selective hydrogenation of BP to CHB was also discussed. [ABSTRACT FROM AUTHOR]

Furfuryl alcohol represents a pivotal intermediate in the high-value utilization of renewable furfural, derived from agricultural residues. The industrial-scale hydrogenation of furfural to furfuryl alcohol typically employs Cu-based catalysts, but their limited catalytic activity necessitates high-temperature and high-pressure conditions. Here, we develop robust CuNi bimetallic catalysts through direct calcination of dried sol–gel precursors under H2 atmosphere, enabling the complete conversion of furfural to furfuryl alcohol under mild conditions. By adjusting the calcination atmosphere and introducing small amounts of Ni, we achieve the formation of highly dispersed, ultrasmall Cu nanoparticles, resulting in a significant enhancement of the catalytic activity. The optimized 0.5%Ni-10%Cu/SiO2-CA(H2) catalyst demonstrates superior catalytic performance, achieving 99.4% of furfural conversion and 99.9% of furfuryl alcohol selectivity, respectively, at 55 °C under 2 MPa H2, outperforming previously reported Cu-based catalysts. The excellent performance of CuNi bimetallic catalysts can be attributed to the highly dispersed Cu nanoparticles and the synergistic effect between Cu and Ni for H2 activation. This research contributes to the rational design of Cu-based catalysts for the selective hydrogenation of furfural. [ABSTRACT FROM AUTHOR]

A novel thermoregulated phase-transfer（TPT）catalysis system composed of H2O, 1-hexanol and Ru nanocatalyst （Runano catalyst） was developed and utilized for the selective hydrogenation of chalcone at atmospheric H2 pressure. Under the optimal circumstances, both the conversion of chalcone and the selectivity for the product of C==C double bond hydrogenation from chalcone were above 99%. The Runano catalyst is conveniently separable from product and directly recycled six times with conversion and selectivity remaining unchanged. The turnover frequency（TOF）was higher than that of previously reported Runano catalyst and the leaching of Ru was further reduced. In addition, this novel TPT catalysis system was also extended to the atmospheric hydrogenation of other α, β -unsaturated ketones with ＞99% conversion and selectivity [ABSTRACT FROM AUTHOR]

[Display omitted] • FeO x can optimize the catalyst structure and stabilize the catalyst performance. • FeO x more conducive to the adsorption of nitro and the desorption of the product. • FeO x can effectively mask some acid sites, inhibit the hydrolysis of CHO. • The Cu+ interface carries out the adsorption and desorption of the reactants. • CuFeAl catalyst showes best performance for converting NCH to CHO (yield: > 93 %). Nitrocyclohexane (NCH) hydrogenation to cyclohexanone oxime (CHO) is of great significance in the production of caprolactam. In this work, CuFeAl-Layered Double Hydroxide (CuFeAl-LDH) catalysts with lamellar structure were prepared by co-precipitation method and applied for NCH hydrogenation, and the promoting role of FeO x was discussed. It was found that FeO x species promote the reduction of Cu2+ and control the ratio of Cu+ to Cu0. In situ DRIFT and density-functional theory (DFT) calculation results confirm that the presence of FeO x species can act as lewis base site to reduce the acid sites and facilitate the isomerization of nitrosocyclohexane to CHO, and promotes the adsorption of NCH and the desorption of the formed CHO to prevent its further reaction to form byproducts. CuFe 0.05 Al shows the best catalytic performance of 100 % NCH conversion and 93.35 % selectivity to CHO under mild conditions. This work provides a new idea for the design of non-noble metal-based catalysts with high activity for the selective hydrogenation of nitro compounds. [ABSTRACT FROM AUTHOR]

Single‐atom alloys (SAAs) have gained increasing prominence in the field of selective hydrogenation reactions due to their uniform distribution of active sites and the unique host‐guest metal interactions. Herein, 15 SAAs are constructed to comprehensively elucidate the relationship between host‐guest metal interaction and catalytic performance in the selective hydrogenation of 4‐nitrostyrene (4‐NS) by density functional theory (DFT) calculations. The results demonstrate that the SAAs with strong host‐guest metal interactions exhibit a preference for N─O bond cleavage, and the reaction energy barrier of the hydrogenation process is primarily influenced by the host metal. Among them, Ir1Ni SAA stands out as the prime catalyst candidate, showcasing exceptional activity and selectivity. Furthermore, the Ir1Ni SAA is subsequently prepared through precise synthesis techniques and evaluated in the selective hydrogenation of 4‐NS to 4‐aminostyrene (4‐AS). As anticipated, the Ir1Ni SAA demonstrates extraordinary catalytic performance (yield > 96%). In situ FT‐IR experiments and DFT calculations further confirmed that the unique host‐guest metal interaction at the Ir‐Ni interface site of Ir1Ni SAA endows it with excellent 4‐NS selective hydrogenation ability. This work provides valuable insights into enhancing the performance of SAAs catalysts in selective hydrogenation reactions by modulating the host‐guest metal interactions. [ABSTRACT FROM AUTHOR]

The selective hydrogenation of the biomass platform molecule furfural (FAL) to produce furfuryl alcohol (FA) is of great significance to alleviate the energy crisis. Cu-based catalysts are the most commonly used catalysts, and their catalytic performance can be optimized by changing the preparation method. This paper emphasized the effect of calcination atmosphere on the performance of a Cu/Al2O3 catalyst for the selective hydrogenation of FAL. The precursor of the Cu/Al2O3 catalyst prepared by the ammonia evaporation method was treated with different calcination atmospheres (N2 and air). On the basis of the combined results from the characterizations using in situ XRD, TEM, N2O titration, H2-TPR and XPS, the Cu/Al2O3 catalyst calcined in the N2 atmosphere was more favorable for the dispersion and reduction of Cu species and the reduction process could produce more Cu+ and Cu0 species, which facilitated the selective hydrogenation of FAL to FA. The experimental results showed that the N2 calcination atmosphere improved the FAL conversion and FA selectivity, and the FAL conversion was further increased after reduction. Cu/Al2O3-N2-R exhibited the outstanding performance, with a high yield of 99.9% of FA after 2 h at 120 °C and an H2 pressure of 1 MPa. This work provides a simple, efficient and economic method to improve the C=O hydrogenation performance of Cu-based catalysts. [ABSTRACT FROM AUTHOR]

A new hybrid catalyst consisting of cobalt nanoparticles immobilized onto cellulose was developed. The cellulosic matrix is derived from date palm biomass waste, which was oxidized by sodium periodate to yield dialdehyde and was further derivatized by grafting orthoaminophenol as a metal ion complexing agent. The new hybrid catalyst was characterized by FT-IR, solid-state NMR, XRD, SEM, TEM, ICP, and XPS. The catalytic potential of the nanocatalyst was then evaluated in the catalytic hydrogenation of 4-nitrophenol to 4-aminophenol under mild experimental conditions in aqueous medium in the presence of NaBH4 at room temperature. The reaction achieved complete conversion within a short period of 7 min. The rate constant was calculated to be K = 8.7 × 10−3 s−1. The catalyst was recycled for eight cycles. Furthermore, we explored the application of the same catalyst for the hydrogenation of cinnamaldehyde using dihydrogen under different reaction conditions. The results obtained were highly promising, exhibiting both high conversion and excellent selectivity in cinnamyl alcohol. [ABSTRACT FROM AUTHOR]

Cost‐effective non‐noble metal‐based catalysts for selective hydrogenation with excellent activity, selectivity, and durability are still the holy grail. Herein, an oxygen‐doped carbon (OC) chainmail encapsulated dilute Cu–Ni alloy is developed by simple pyrolysis of Cu/Ni‐metal–organic framework. The CuNi0.05@OC catalyst displays superior performance for atmospheric pressure transfer hydrogenation of p‐chloronitrobenzene and p‐nitrophenol, and for hydrogenation of furfural, all in water and with exceptional durability. Comprehensive characterizations confirm the close interactions between the diluted Ni sites, the base Cu, and optimized three‐layered graphene chainmail. Theoretical calculations demonstrate that the properly tuned lattice strain and Schottky junction can adjust electron density to facilitate specific adsorption on the active centers, thus enhancing the catalytic activity and selectivity, while the OC shell also offers robust protection. This work provides a simple and environmentally friendly strategy for developing practical heterogeneous catalysts that bring the synergistic effect into play between dilute alloy and functional carbon wrapping. [ABSTRACT FROM AUTHOR]

The catalytic conversion of naturally rich and renewable biomass into high-value chemicals is of great significance for pursuing a sustainable future and a green economy. The preparation of pentanediol from furfuryl alcohol is an important means of high-value conversion of biomass. The Pt-based catalyst supported on MgO was applied to the selective hydrogenation of biomass furfuryl alcohol to prepare pentanediol. By adjusting parameters such as catalyst loading, reduction temperature, reaction temperature, and pressure, a highly active catalyst was designed and the optimal catalytic hydrogenation conditions were determined. The hydrogenation experiment results showed that the selectivity of the 2Pt/MgO-200 catalyst for 1,2-pentanediol and 1,5-pentanediol reached 59.4% and 15.2%, respectively, under 160 °C and 1 MPa hydrogen pressure. The catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectrometer (XPS), CO2-temperature programmed desorption (CO2-TPD), and other methods. The characterization results indicate that the reduction temperature has a significant impact on the metal Pt, and an appropriate reduction temperature is beneficial for the hydrogenation performance of the catalyst. In addition, the basic sites on the carrier are also another important factor affecting the activity of the catalyst. In addition, stability tests were conducted on the catalyst, and the reasons for catalyst deactivation were studied using methods such as thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The results showed that the activity of the catalyst decreased after five cycles, and the deactivation was due to the hydrolysis of the carrier, the increase in metal particle size, and the surface adsorption of organic matter. [ABSTRACT FROM AUTHOR]

Zinc-included intermetallic compound catalysts of RhZn, PtZn, and PdZn with a molar ration of Zn/metal = 1/1, which are generally prepared using a hydrogen reduction approach, are known to show excellent catalytic performance in some selective hydrogenations of organic compounds. In this study, in order to reduce the incorporated mounts of the expensive noble metals, we attempted to prepare zinc-rich intermetallic compounds via a CaH2-assisted molten salt synthesis method with a stronger reduction capacity than the common hydrogen reduction method. X-ray diffraction results indicated the formation of RhZn13 and Pt3Zn10 in the samples prepared by the reduction of ZnO-supported metal precursors. In a hydrogenation reaction of p-nitrophenol to p-aminophenol, the ZnO-supported RhZn13 and Pt3Zn10 catalysts showed a higher selectivity than the RhZn/ZnO and PtZn/ZnO catalysts with the almost similar conversions. Thus, it was demonstrated that the zinc-rich intermetallic compounds of RhZn13 and Pt3Zn10 could be superior selective hydrogenation catalysts compared to the conventional intermetallic compound catalysts of RhZn and PtZn. [ABSTRACT FROM AUTHOR]

Abstract Single‐atom alloys (SAAs) have gained increasing prominence in the field of selective hydrogenation reactions due to their uniform distribution of active sites and the unique host‐guest metal interactions. Herein, 15 SAAs are constructed to comprehensively elucidate the relationship between host‐guest metal interaction and catalytic performance in the selective hydrogenation of 4‐nitrostyrene (4‐NS) by density functional theory (DFT) calculations. The results demonstrate that the SAAs with strong host‐guest metal interactions exhibit a preference for N─O bond cleavage, and the reaction energy barrier of the hydrogenation process is primarily influenced by the host metal. Among them, Ir1Ni SAA stands out as the prime catalyst candidate, showcasing exceptional activity and selectivity. Furthermore, the Ir1Ni SAA is subsequently prepared through precise synthesis techniques and evaluated in the selective hydrogenation of 4‐NS to 4‐aminostyrene (4‐AS). As anticipated, the Ir1Ni SAA demonstrates extraordinary catalytic performance (yield > 96%). In situ FT‐IR experiments and DFT calculations further confirmed that the unique host‐guest metal interaction at the Ir‐Ni interface site of Ir1Ni SAA endows it with excellent 4‐NS selective hydrogenation ability. This work provides valuable insights into enhancing the performance of SAAs catalysts in selective hydrogenation reactions by modulating the host‐guest metal interactions.

A novel photocatalytic strategy was proposed for selectively reducing alkynols to corresponding alkenols under ambient temperature and pressure. Carbon nitride nanosheets with Pd nanoparticles as cocatalysts exhibit high alkynol conversion and alkenol selectivity, which potentially replaces the current thermocatalysis and electrocatalysis. [Display omitted] Selective hydrogenation of alkynols to alkenols is an essential process for producing fine and intermediate chemicals. Currently, thermocatalytic alkynol hydrogenation faces several challenges, e.g., the safety of high-pressure hydrogen (H 2) gas and the need for elevated temperature, and unavoidable side reactions, e.g., overhydrogenation. Here, a novel photocatalytic strategy is proposed for selectively reducing alkynols to alkenols with water as a hydrogen source under ambient temperature and pressure. Under the irradiation of simulated solar light, carbon nitride (C 3 N 4) nanosheets with palladium (Pd) nanoparticles as cocatalysts (Pd–C 3 N 4 NSs) exhibit a 2-methyl-3-butyn-2-ol (MBY) conversion of 98% and 2-methyl-3-buten-2-ol (MBE) selectivity of 95%, outperforming state-of-the-art thermocatalysts and electrocatalysts. After natural-sunlight irradiation (average light intensity of 25.13 mW cm−2) for 36 h, a MBY conversion of 98% and MBE selectivity of 92% was achieved in a large-scale photocatalytic system (2500 cm2). Experimental and theoretical investigations reveal that Pd cocatalysts on C 3 N 4 facilitate the adsorption and hydrogenation of MBY as well as the formation of active hydrogen species, which promote the selective semihydrogenation of alkynols. Moreover, the proposed strategy is applicable to various water-soluble alkynols. This work paves the way for photocatalytic strategies to replace thermocatalytic hydrogenation processes using pressurized hydrogen. [ABSTRACT FROM AUTHOR]

The passivation of hydrogen atoms and the conformation of textured surfaces under oil-lubricated conditions are effective strategies to obtain amorphous carbon (a-C) films with extremely low friction. It is critical to understanding the influence mechanism of selective surface hydrogenation on the tribological behaviors of textured a-C film under oil-lubricated conditions. In particular, the interactions of hydrogen atoms and lubricants are confusing, which is enslaved to the in situ characterization technique. The reactive molecular dynamics (RMD) simulations were conducted to analyze the friction response of textured a-C films with selective hydrogenation surfaces under oil-lubricated conditions. The results indicate that the existence of hydrogen atoms on specific bump sites significantly decreases the friction coefficient (μ) of textured a-C film, which is highly dependent on the surface hydrogen content. The repulsion between hydrogen atoms and lubricant molecules prompts the formation of a dense lubricant film on the surface of the mating material. Interestingly, with the enhancement of the surface hydrogen content, the passivation of the friction interface and the repulsion between hydrogen atoms and lubricants play dominant roles in reducing the friction coefficient instead of hydrodynamic lubrication. [ABSTRACT FROM AUTHOR]

Abstract Cost‐effective non‐noble metal‐based catalysts for selective hydrogenation with excellent activity, selectivity, and durability are still the holy grail. Herein, an oxygen‐doped carbon (OC) chainmail encapsulated dilute Cu–Ni alloy is developed by simple pyrolysis of Cu/Ni‐metal–organic framework. The CuNi0.05@OC catalyst displays superior performance for atmospheric pressure transfer hydrogenation of p‐chloronitrobenzene and p‐nitrophenol, and for hydrogenation of furfural, all in water and with exceptional durability. Comprehensive characterizations confirm the close interactions between the diluted Ni sites, the base Cu, and optimized three‐layered graphene chainmail. Theoretical calculations demonstrate that the properly tuned lattice strain and Schottky junction can adjust electron density to facilitate specific adsorption on the active centers, thus enhancing the catalytic activity and selectivity, while the OC shell also offers robust protection. This work provides a simple and environmentally friendly strategy for developing practical heterogeneous catalysts that bring the synergistic effect into play between dilute alloy and functional carbon wrapping.

The selective hydrogenation of the biomass platform molecule furfural (FAL) to produce furfuryl alcohol (FA) is of great significance to alleviate the energy crisis. Cu-based catalysts are the most commonly used catalysts, and their catalytic performance can be optimized by changing the preparation method. This paper emphasized the effect of calcination atmosphere on the performance of a Cu/Al2O3 catalyst for the selective hydrogenation of FAL. The precursor of the Cu/Al2O3 catalyst prepared by the ammonia evaporation method was treated with different calcination atmospheres (N2 and air). On the basis of the combined results from the characterizations using in situ XRD, TEM, N2O titration, H2-TPR and XPS, the Cu/Al2O3 catalyst calcined in the N2 atmosphere was more favorable for the dispersion and reduction of Cu species and the reduction process could produce more Cu+ and Cu0 species, which facilitated the selective hydrogenation of FAL to FA. The experimental results showed that the N2 calcination atmosphere improved the FAL conversion and FA selectivity, and the FAL conversion was further increased after reduction. Cu/Al2O3-N2-R exhibited the outstanding performance, with a high yield of 99.9% of FA after 2 h at 120 °C and an H2 pressure of 1 MPa. This work provides a simple, efficient and economic method to improve the C=O hydrogenation performance of Cu-based catalysts.

Abstract The passivation of hydrogen atoms and the conformation of textured surfaces under oil-lubricated conditions are effective strategies to obtain amorphous carbon (a-C) films with extremely low friction. It is critical to understanding the influence mechanism of selective surface hydrogenation on the tribological behaviors of textured a-C film under oil-lubricated conditions. In particular, the interactions of hydrogen atoms and lubricants are confusing, which is enslaved to the in situ characterization technique. The reactive molecular dynamics (RMD) simulations were conducted to analyze the friction response of textured a-C films with selective hydrogenation surfaces under oil-lubricated conditions. The results indicate that the existence of hydrogen atoms on specific bump sites significantly decreases the friction coefficient (μ) of textured a-C film, which is highly dependent on the surface hydrogen content. The repulsion between hydrogen atoms and lubricant molecules prompts the formation of a dense lubricant film on the surface of the mating material. Interestingly, with the enhancement of the surface hydrogen content, the passivation of the friction interface and the repulsion between hydrogen atoms and lubricants play dominant roles in reducing the friction coefficient instead of hydrodynamic lubrication.

In confined mesoscopic spaces, the unraveling of a catalytic mechanism with complex mass transfer and adsorption processes such as reactant enrichment is a great challenge. In this study, a hollow nanoarchitecture of MnOx-encapsulated Pt nanoparticles was designed as a nanoreactor to investigate the reactant enrichment in a mesoscopic hollow void. By employing advanced characterization techniques, we found that the reactant-enrichment behavior is derived from directional diffusion of the reactant driven through the local concentration gradient and this increased the amount of reactant. Combining experimental results with density functional theory calculations, the superior cinnamyl alcohol (COL) selectivity originates from the selective adsorption of cinnamaldehyde (CAL) and the rapid formation and desorption of COL in the MnOx shell. The superb performance of 95% CAL conversion and 95% COL selectivity is obtained at only 0.5 MPa H2 and 40 min. Our findings showcase that a rationally designed nanoreactor could boost catalytic performance in chemoselective hydrogenation, which can be of great aid and potential in various application scenarios. [ABSTRACT FROM AUTHOR]

Many research papers describe selective hydrogenation of functional groups, such as nitro groups, carbonyl groups, or unsaturated carbon bonds to obtain fine chemicals or precursors of pharmaceuticals. Quite often, the catalyst performance is investigated in batch or continuous flow reactors without finding advantages and disadvantages of this or that regime. At the same time, the transition from batch processes to continuous flow occurs on the industrial scale. However, the batch process can be preferable for some reactions, in spite of its drawbacks. This review article aims to identify all publications that consider selective hydrogenation of functional groups in organic compounds, both in batch and continuous flow reactors, at the same reaction conditions that allow making conclusions about the benefits of one of the regimes in a particular case. [ABSTRACT FROM AUTHOR]

[Display omitted] • CNT supported Ru single atoms have been associated to Ru, Pd and Ni particles. • Hydrogen spillover induced a cooperative catalysis between supported Pd and Ni particles and Ru single atoms. • The RuNi/CNT catalyst contains a cocktail of catalytic species including isolated Ru single atoms and Ru single atoms on Ni particles. • The RuNi/CNT catalyst shows much better performances in terms of activity and selectivity compared to the monometallic systems. • DFT calculations revealed that the active species is a Ru SA @Ni NP single atom alloy. Reaching high selectivity at high conversion and high rate in the industrially important selective hydrogenation of α,β-unsaturated aldehydes is a challenging task. Among current approaches reported in the literature, high selectivity towards the unsaturated alcohol or saturated aldehyde is generally achieved at the expense of activity. The use of bimetallic systems can lead either to selectivity or to activity enhancement, but generally not to both. Herein, we show that, for cinnamaldehyde hydrogenation, combining Ni nanoparticles (Ni NP) and Ru single atoms (Ru SA) on CNTs allows improvement of the hydrocinnamaldehyde selectivity, while obtaining a remarkable activity. The STY of Ru SA -Ni NP /CNT is approximately 60 times higher than that of the Ru SA /CNT and 10 times higher than that of the Ni NP /CNT. Importantly, the resulting catalyst shows 94% selectivity at 99% conversion and a good stability in flow. Insights into the cooperative "cocktail"-type catalysis between Ni NP and Ru SA were revealed from density functional theory calculations. [ABSTRACT FROM AUTHOR]

Selective hydrogenation of phenol to cyclohexanone is intriguing in chemical industry. Though a few catalysts with promising performances have been developed in recent years, the basic principle for catalyst design is still missing owing to the unclear catalytic mechanism. This work tries to unravel the mechanism of phenol hydrogenation and the reasons causing the selectivity discrepancy on noble metal catalysts under mild conditions. Results show that different reaction pathways always firstly converge to the formation of cyclohexanone under mild conditions. The selectivity discrepancy mainly depends on the activity for cyclohexanone sequential hydrogenation, in which two factors are found to be responsible, i.e. the hydrogenation energy barrier and the competitive chemisorption between phenol and cyclohexanone, if the specific co-catalyzing effect of H2O on Ru is not considered. Based on the above results, a quantitative descriptor, Eb(one/pl)/Ea, in which Ea can be further correlated to the d band center of the noble metal catalyst, is proposed by the first time to roughly evaluate and predict the selectivity to cyclohexanone for catalyst screening.

The adsorption of crotonaldehyde on Cu-Pt alloy surfaces was characterized by density functional theory (DFT). Two surfaces were considered: Cu2Pt/Cu(111) and Cu3Pt/Cu(111). It was determined that the presence of Pt on the surface, even when isolated as single atoms fully surrounded by Cu, provides additional stability for the adsorbates, increasing the magnitude of the adsorption energy by as much as 40 kJ/mol. The preferred bonding on both surfaces is via multiple coordination, with the most stable configuration being a cis arrangement with di-σ bonding of the C=O bond across a Cu–Cu bridge and an additional π bonding to a Pt atom. The fact that Pt significantly affects the adsorption of unsaturated aldehydes such as crotonaldehyde explains why the kinetics of their hydrogenation using single-atom alloy (SAA) catalysts vary with alloy composition, as we previously reported, and brings into question the simple model in which the role of Pt is only to promote the dissociation of H2.

Lignin, as a structurally complex biomaterial, offers a valuable resource for the production of aromatic chemicals; however, its selective conversion into desired products remains a challenging task. In this study, we prepared three types of Pd-based nano-catalysts and explored their application in the depolymerization of alkali lignin, under both H2-free (hydrogen transfer) conditions and H2 atmosphere conditions. The materials were well characterized with TEM, XRD, and XPS and others, and the electronic interactions among Pd, Ni, and P were analyzed. The results of lignin depolymerization experiments revealed that the ternary Pd-Ni-P catalyst exhibited remarkable performance and guaiacols could be produced under H2 atmosphere conditions in 14.2 wt.% yield with a selectivity of 89%. In contrast, Pd-Ni and Pd-P catalysts resulted in a dispersed product distribution. Considering the incorporation of P and the Pd-Ni synergistic effect in the Pd-Ni-P catalyst, a possible water-involved transformation route of lignin depolymerization was proposed. This work indicates that metal phosphides could be promising catalysts for the conversion of lignin and lignin-derived feedstocks into value-added chemicals. [ABSTRACT FROM AUTHOR]

The selective hydrogenation of chalcone to dihydrochalcone under atmospheric hydrogen pressure is investigated using a thermoregulated phase-transfer ruthenium nanocatalyst, representing the first ruthenium nanocatalyst used for this reaction. Under the optimal conditions, the conversion of chalcone into dihydrochalcone and the selectivity are 98% and >99%, respectively. The ruthenium catalyst can be easily separated from the product and recycled three times without any decrease in the conversion or selectivity. The turnover frequency is higher than that of a reported ruthenium complex catalyst. The thermoregulated phase-transfer ruthenium nanocatalyst is also applied for the atmospheric hydrogenation of other α,β-unsaturated ketones. [ABSTRACT FROM AUTHOR]

Selective hydrogenation of anthraquinone is critical in producing H2O2, the strong oxidant widely used in most industrial areas. More efforts were made on the selective hydrogenation of C=O in the anthraquinone process because the sides-product will negatively affect continuous H2O2 production and significantly reduce the project economics. A crucial step toward high H2O2 yield is the rational design of heterogeneous catalysts. In this review, the metal-based catalyst design for the selective anthraquinone hydrogenation is cataloged into two significant strategies: active metal regulation and support property regulation. Research accomplished in the past decade on the catalyst design for selective anthraquinone hydrogenation is systematically reviewed. The focus is on the catalytic performance-enhancing mechanism and the factors that influence the mechanism. In addition, the limitations and barriers encountered for supported catalysts in the current study, as well as potential research trends, are discussed. [ABSTRACT FROM AUTHOR]

The effect of nickel precursors and the temperature annealing to obtain intermetallic Ni3Sn2 alloy catalysts on its activity and selectivity in the selective hydrogenation of biomass-derived furfural (FFald) were investigated. Two types of nickel precursors (c.a., i) nickel metal (Ni°) derived from Raney®nickel and ii) nickel ion (Ni2+) derived from nickel chloride) were employed as the starting materials via hydrothermal at 423 K for 24 h followed by reduction with H2 at the elevated temperature of 573-873 K for 1.5 h. The physico-chemical properties of the intermetallic Ni3Sn2 were characterized by XRD, N2-, and H2-adsorption, ICP-AES, and NH3-TPD. The intermetallic Ni3Sn2 alloy catalysts, both bulk and supported, demonstrated high activity and selectivity towards hydrogenation of FFald. The activity and selectivity of g-Al2O3 and AA-supported Ni3Sn2 alloy catalysts in the hydrogenation of FFald to furfuryl alcohol (FFalc) were maintained even after annealing at up to 873 K, but that of bulk Ni3Sn2 drastically dropped. Ni-Sn alloy catalysts which were obtained from Raney®Ni precursor showed more stable than that of nickel salts during hydrogenation of furfural to furfuryl alcohol. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Photocatalyst-enzyme coupling process for visible light driven biotransformation holds promise in producing solar chemicals. In this work, aiming to produce furfuryl alcohol, the important bulk chemical that is typically derived from renewable lignocellulose, a highly selective furfural hydrogenation process is proposed by coordinating the alcohol dehydrogenase with the ZnIn2S4 assistant reduced form of nicotinamide adenine dinucleotid (NADH) regeneration. Results indicated that under visible light irradiation, the hierarchical ZnIn2S4 microspheres exhibited excellent holes and electrons separating efficiency, affording to high NADH regeneration (yield of 90.2±3.28%). When adopting the photo-biocoupled reduction process in furfural transformation, a furfuryl alcohol yield of 79.4±1.95% was achieved under the optimized conditions. The photocatalyst-enzyme coupling process also showed good stability, exceeding 70% of catalytic activity was reserved after reusing the catalysts for 10 cycles. The novel photo-biocoupled system showed promising in extending to the highly selective hydrogenation of other biochemicals from lignocelluloses.

In this study, nanosheet g-C3N4-H2 was prepared by thermal exfoliation of bulk g-C3N4 under hydrogen. A series of Ru/g-C3N4-H2 catalysts with Ru species supported on the nanosheet g-C3N4-H2 were synthesized via ultrasonic assisted impregnation-deposition method. Ultrafine Ru nanoparticles (99% 4,4′-diaminodicyclohexylmethane selectivity, corresponding to a reaction activity of 35.7 molMDA molRu−1 h−1. Moreover, the reaction activity of catalyst in the fifth run was 36.5 molMDA molRu−1 h−1, which was comparable with that of the fresh one. The computational results showed that g-C3N4 as support was favorable for adsorption and dissociation of H2 molecules. Moreover, the substrate scope can be successfully expanded to a variety of other aromatic diamines. Therefore, this work provides an efficient and green catalyst system for selective hydrogenation of aromatic diamines.

2,5-Bis(hydroxymethyl)furan (BHMF) is a high-value, bio-based, rigid diol that resembles aromatic monomers for the production of different polyesters. In this work, a carbon nanotubes (CNTs)-supported nickel catalyst (Ni/CNTs) was prepared and used for the selective hydrogenation of 5-hydroxymethylfurfural (HMF) to BHMF at low hydrogen pressure. The prepared catalyst was analyzed by nitrogen adsorption–desorption isotherms, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). According to kinetic studies, the rate constant for BHMF formation is significantly larger than that for the formation of the byproduct, 5-methyl furfural (MF). At optimal reaction conditions, conversion and selectivity rates of HMF and BHMF were 99.8 % and 95.0 %, respectively. The mechanistic study indicated the coexistence of Ni0 and Ni2+ species on the catalyst surface affects the catalytic performance. A possible mechanism was proposed to describe the synergetic effects of Ni0 and Ni2+. Furthermore, the catalyst can be easily separated from the reaction mixture for recycling.

The synthesis of sustainable methanol and ethylene glycol (EG) via hydrogenation of ethylene carbonate (EC) has caught researchers’ growing interests on account of the indirect chemical utilization of CO2. Core-shell Cu@GO catalysts with random nanoporous network of graphite oxide (GO) were synthesized via a simple method of ultrasonic precipitation. Cu@GO catalysts were analyzed systematically by N2 physisorption, TGA measurement, XRD, FT-IR, Raman, TEM, SEM, and XPS (XAES). In particular, the mentioned method was confirmed to be effective to fabricate the high dispersity core-shell Cu@GO catalysts through promoting the specific surface area. The as-prepared Cu@GO catalyst was then successfully applied in the hydrogenation of CO2-derived EC to produce methanol and EG. A high TOF of 1526 mgEC gcat-1 h-1 could be attained in EC hydrogenation at the reaction temperature of 493 K. Accordingly, the correlation of catalytic structure and performance disclosed that the synergistic effect between Cu+ and Cu0 was responsible for achieving high activity of the catalyst. In addition, the reusability of Cu@GO catalyst suggested that graphite oxide shell structure could decrease the aggregation of Cu particles, thus enhance the stability of Cu-based catalysts. DFT calculation results suggested that the involvement of carbon film on Cu was favorable for the stabilization of the active sites. This study is helpful for developing new and stable catalytic system for indirect chemical utilization of CO2 to synthesize commodity methanol and EG.

[Display omitted] • Remarkable structure sensitivity of DADNP hydrogenation over Ni catalysts. • Two competitive reaction routes for the formation of TAP from DADNP. • Microkinetics model well describing size-dependent kinetics of DADNP hydrogenation. • Increasing k´ TAP2 / k´ TAP1 with the increasing Ni particle sizes. • More favorable flat adsorption of DADNP on larger sized Ni catalyst. Designing cost-effective Ni-based catalysts with satisfactory performance for the hydrogenation of 2,6-diamino-3,5-dinitropyridine (DADNP) to 2,3,5,6-tetraaminopyridine (TAP) is highly essential for producing high-performance poly (pyridobisimidazole) but remains a great challenge due to the limited mechanistic and kinetics understandings. Herein, a series of differently sized Ni catalysts but similar electronic properties are synthesized to explore the size-dependent kinetics behaviors of the hydrogenation of DADNP via two competitive routes. The results unravel that the hydrogenation of DADNP to TAP via the route 2, i.e., the formation of TAP from the direct hydrogenation of DADNP without being intermediated by the 2,3,6-triamino-5-nitropyridine (TANP), appears to be more prominent on larger sized Ni catalysts. Microkinetics studies based on the Langmuir-Hinshelwood-Hougen-Watson model indicate that the ratio of the TAP formation rates via these two routes, i.e., k´ TAP2 / k´ TAP1 , increases with the increasing Ni particle size, confirming the more favorable formation of TAP via the route 2 on larger sized Ni catalysts. These size-dependent kinetics behaviors are further rationalized by DFT calculations, which reveal that the simultaneous activation of both nitro groups of DADNP via flat adsorption is more likely to occur on the larger size Ni catalysts than that on the smaller sized ones. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ionic liquids (IL) as a heteroatomic doping source is proposed. • N and P co-doping catalyst (Co@NPC) is synthesized by a simple method. • Co@NPC shows high catalytic performance in chemoselective hydrogenation. • N and P atoms display a synergistic effect of geometry and electrons in Co@NPC. • DFT calculation reveals the important role of di-heteroatoms doping. • Co@NPC can maintain its activity for 5 times cycle experiments. Exploring the interactions among doping heteroatom, carbon and metal atoms has great potential to significantly enhance the catalytic performance and can gain an insightful understanding of the heterogeneous catalysis mechanism. Here, we present an N,P co-doped carbon-coated cobalt (Co@NPC) as a highly selective and water-durable catalyst applicable to aqueous-phase hydrogenation of cinnamaldehyde, featuring a precise control of products by adjusting N and P doping. These di-heteroatoms display a synergistic effect of geometry and electrons in Co@NPC, thus can selectively reduce C O to produce unsaturated alcohols. In contrast, Co@NC without P doping is highly active, but shows significant productivity of saturated alcohols under equivalent conditions. Theoretical calculations manifest that the electronegativity difference among N, C and P atoms leads to the interaction between electrons, thus can adjust the chemical states of the active metal and enhance the catalytic performance in hydrogenation. It provides a desirable way for regulating the catalysis of heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hybrid nano-structured catalyst Pt/@-ZrO 2 /SBA-15 was fabricated. • Metal-metal oxide synergistic catalysis for high efficiency selective hydrogenation. • Metal oxide dispersed on the support at the state of the spontaneous mono-layer distribution. It is generally believed that noble metal catalysts exhibited higher activity for selective hydrogenation, while metal oxides were almost inactive. Here, we report metal-metal oxide synergistic catalysis for high efficiency selective hydrogenation by a hybrid nano-structure Pt/@-ZrO 2 /SBA-15 catalyst, which was fabricated by anchored Pt nanoparticles on the mono-layer dispersed ZrO 2 film layer coated in SBA-15 support via a photochemical route. This Pt/@-ZrO 2 /SBA-15 catalyst exhibited remarkable catalytic activity in the selective hydrogenation of C O bond, NO 2 , and C C bond. For the selective hydrogenation of benzaldehyde, conversion >99.9% was achieved with >99% selectivity, and the turnover frequency (TOF) can be achieved up to 4822 h−1, which was much higher than that of the atomically dispersed Pd 1 /TiO 2 -EG catalyst (1002 h−1) reported in the literature, no decay in the activity was observed by several cycles. Combined the experimental and characterization results, proved that the ZrO 2 was dispersed in a mono-layer in the channel of SBA-15, and the results showed that an appropriate loading of ZrO 2 in this catalyst could maximize the advantage of this hybrid nano-structure to achieve the best catalytic activity. The superior activity of Pt/@-ZrO 2 /SBA-15 was attributed to the synergistic catalysis, strong interface electronic effect, and the unique properties of the special hybrid nano-structure. This work demonstrated synergistic catalysis of metal Pt nanoparticles and monolayer dispersion ZrO 2 for high efficiency selective hydrogenation. [ABSTRACT FROM AUTHOR]

Currently, microwave radiation is widely used in various chemical processes in order to intensify them and carry out processes within the framework of "green" chemistry approaches. In the last 10 years, there has been a significant increase in the number of scientific publications on the application of microwaves in catalytic reactions and synthesis of nanomaterials. It is known that heterogeneous catalysts obtained under microwave activation conditions have many advantages, such as improved catalytic characteristics and stability, and the synthesis of nanomaterials is accelerated several times compared to traditional methods used to produce catalysts. The present review article is to summarize the results of modern research on the use of microwave radiation for the synthesis of heterogeneous catalytic nanomaterials and discusses the prospects for research in the field of microwave-induced liquid-phase heterogeneous catalysis in hydrogenation. [ABSTRACT FROM AUTHOR]

The influence of the catalyst Sn content on the production of fatty alcohol from oleic acid by selective hydrogenation was studied using Rh‐Sn‐B catalysts supported on TiO2. The crystal phase of the support was analyzed by X‐ray diffraction (XRD), the reduction state of the metal phase by temperature‐programmed reduction (TPR), and the electronic state of surface species by X‐ray photoelectron spectroscopy (XPS). The metal activity was evaluated by the dehydrogenation of cyclohexane. It was found that the increase in Sn content leads to a proportional drop in the catalytic activity, which could be related to a metallic interaction between Rh and Sn, as shown by TPR. Oxide and metallic Sn, as well as Rh0 and Rh3+, were found by XPS on the catalyst surface. Metallic Rh was, however, found in higher concentration than oxidized Rh in all cases. The yield to fatty alcohols increased with Sn content, and its maximum value for oleyl and stearyl alcohol was 96%. Furthermore, a higher yield (88.3%) was obtained out of unsaturated fatty alcohol (oleyl alcohol), which has proved to be more valuable than saturated alcohol. This was attributed to an adequate Rh/Sn ratio, which modulates the hydrogenating activity of Rh and makes the metal function more selective for hydrogenation of the carbonyl group. The influence of the support on the catalyst performance decreases as the Sn content increases. The support has a practically negligible influence on the catalyst activity for 4–5 wt.% of Sn content. [ABSTRACT FROM AUTHOR]

Allylic alcohols typically produced through selective hydrogenation of α,β-unsaturated aldehydes are important intermediates in fine chemical industry, but it is still a challenge to achieve its high selectivity transformation. Herein, we report a series of TiO2-supported CoRe bimetallic catalysts for the selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL) using formic acid (FA) as a hydrogen donor. The resultant catalyst with the optimized Co/Re ratio of 1:1 can achieve an exceptional COL selectivity of 89% with a CAL conversion of 99% under mild conditions of 140 °C for 4 h, and the catalyst can be reused four times without loss of activity. Meanwhile, the Co1Re1/TiO2/FA system was efficient for the selective hydrogenation of various α,β-unsaturated aldehydes to the corresponding α,β-unsaturated alcohols. The presence of ReOx on the Co1Re1/TiO2 catalyst surface was advantageous to the adsorption of C=O, and the ultrafine Co nanoparticles provided abundant hydrogenation active sites for the selective hydrogenation. Moreover, FA as a hydrogen donor improved the selectivity to α,β-unsaturated alcohols. [ABSTRACT FROM AUTHOR]

The effect of tetrabutylammonium nitrate ([N4444][NO3]) was studied as a surface coating over 1Pd9Ag/Al2O3 and applied in the selective hydrogenation of 1,7-octadiene in a mixture with 1-octene. Weight loadings up to a surface of three monolayers (MLs) were investigated and a further comparison coating with 1-ethylimidazole ([EIM]) was carried out to assess anionic effects in the Solid Catalysts with an Ionic Liquid Layer (SCILLs). Catalysts were characterised by H2-chemisorption, TGA-DSC, BET measurements, XPS, and HR-TEM. Catalytic studies showed that the uncoated and EIM-coated (10 wt%) catalysts gave nearly a 100% conversion of 1,7-octadiene and 1-octene with a selectivity mainly towards octane. Coating with [N4444][NO3] at 1 ML significantly decreased the 1-octene conversion by almost 50%, as well as the selectivity to octane (38%) at close to a 100% diene conversion. However, no net gain in 1-octene in the output stream was noted. At 2 ML IL/EIM coverage, a further decline in 1-octene conversion and octane selectivity was found at a diene conversion of 75%. The selectivity to 1-octene steadily increased from over the bare catalyst (52%) to the EIM-coated (62%) catalyst and SCILL (75%). At 3 ML IL coverage, the diene conversion (35%) was significantly reduced due to mass transfer limitations of hydrogen through the thick IL layer. Characterisation of the used catalysts by TG and BET analyses confirmed a leaching of up to 14% of the ionic liquid in the SCILLs coated at 1 ML and 2 ML, with an increase in surface area noted. Furthermore, smaller particle sizes of the used catalysts showed that the metal–support interaction was re-established. These results confirm a mild ligand coordination between the nitrogen in the IL anion and Pd and Ag where the ionic liquid remained physisorbed over the surface of the catalyst. In addition, component miscibility tests revealed partial solubility of the diene in the ionic liquid, indicating the presence of solvent effects also. [ABSTRACT FROM AUTHOR]

The adsorption of crotonaldehyde on Cu-Pt alloy surfaces was characterized by density functional theory (DFT). Two surfaces were considered: Cu2Pt/Cu(111) and Cu3Pt/Cu(111). It was determined that the presence of Pt on the surface, even when isolated as single atoms fully surrounded by Cu, provides additional stability for the adsorbates, increasing the magnitude of the adsorption energy by as much as 40 kJ/mol. The preferred bonding on both surfaces is via multiple coordination, with the most stable configuration being a cis arrangement with di-σ bonding of the C=O bond across a Cu–Cu bridge and an additional π bonding to a Pt atom. The fact that Pt significantly affects the adsorption of unsaturated aldehydes such as crotonaldehyde explains why the kinetics of their hydrogenation using single-atom alloy (SAA) catalysts vary with alloy composition, as we previously reported, and brings into question the simple model in which the role of Pt is only to promote the dissociation of H2. [ABSTRACT FROM AUTHOR]

Pt/Co0.5Fe0.5Al2O4 catalysts with the average Pt particle size of 1.6–3.4 nm were prepared and applied to the selective hydrogenation of cinnamaldehyde (CAL). Not only the TOF was promoted from 0.19 to 2.70 s−1, but also the selectivity to cinnamyl alcohol (COL) was improved from 68% to 94%, with the increase of Pt particle size. Stronger interaction occurred between Co0.5Fe0.5Al2O4 and smaller-sized Pt particles, resulting in electron-deficient Pt particles, so that CO and CC bond could be activated simultaneously. However, electron-rich Pt species existed on Pt/Co0.5Fe0.5Al2O4 with larger Pt size, which is beneficial for the preferential activation of CO bond.

As a material with multifunctional ligands, metal-organic frameworks (MOFs) can effectively regulate the electronic and geometric state of supported metal nanoparticles (MNPs). Herein, a strategy of PtCo alloy incorporated into UiO-66-NH2 hybrid nanoparticles by a facile one-pot solvothermal method was developed. A series of PtCoy@UiO-66-NH2 materials with different Co/Pt ratios were successfully synthesized using CoO as the cobalt source. The obtained PtCo0.80@UiO-66-NH2 exhibited excellent conversion (94.3%) with high selectivity (93.3%) for selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL). Moreover, the formation rate of COL achieved to 5 mol·gPt−1·h−1 as Co/Pt atomic ratio was higher than 0.41. The synergistic effect of Pt, Co and UiO-66-NH2 was investigated by various characterizations. The results revealed that the Lewis acid CoNx favored the linear adsorption of CO bond, and PtCo alloy enhanced activity and selectivity by lowering the activation barrier for CO bond activation and simultaneously suppressing adsorption of CC bond.

High-energy facets exposed nanotubular alumina as well as conventional alumina supported Pd catalysts were synthesized and applied to the selective hydrogenation of phenylacetylene. Novel alumina supported catalyst presented higher selectivity at complete conversion of phenylacetylene. This could be related to the well dispersion of Pd and strong metal-support interaction, which are the consequences of the unique structural properties of the crystal plane regulated alumina. It helps create more active sites for hydrogenation meanwhile facilitates the desorption of alkene and thus suppresses the excess hydrogenation towards ethylbenzene.

Since efficient hydrogenation was valued for manufacture of pharmaceutical intermediates and fragrances in recent years, the development of easily accessible heterogeneous catalysts was preferably made. Here we designed a facile one-pot synthesis of Ni modified COF-derived catalyst for selective catalytic hydrogenation of cinnamaldehyde. The nickel-based COFs catalyst reduced at 600 °C exhibited better catalytic activity for the selective production of hydrocinnamyl with an excellent yield of 98%, and the nickel-based COFs reduced at 500 °C and 700 °C preferred to selectively produce benzenepropanal. Overall, this work proves cost-effective and sustainable access to the wide application of selective hydrogenation reaction.

SiO2-supported NiIr alloy acted as an effective heterogeneous catalyst for the hydrogenation of benzonitrile, crotonaldehyde and benzylideneacetone, showing much higher activity than monometallic Ni/SiO2 and Ir/SiO2 catalysts and superior selectivity to benzyl-benzylidene-amine, butanal and 4-Phenyl-butan-2-one at high conversion. Furthermore, the main active sites were investigated on the basis of the relationship of TOFs and the alloy composition for the hydrogenation of crotonaldehyde, benzonitrile and benzylideneacetone, and the active site was the isolated Ni atom surrounded by Ir atoms for the hydrogenation of crotonaldehyde and related to the structure of substrate in selective hydrogenation.

A bimetallic Pt8Co1 supported on alkali-treated ZSM-5 zeolite (ZSM-5-AT) was prepared through the impregnation method. The structure and surface properties of the catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2-sorption and X-ray photoelectron spectroscopy (XPS) as well as temperature-programmed desorption of NH3 (NH3-TPD) and temperature-programmed reduction of H2 (H2-TPR). The TEM images present that the bimetallic Pt8Co1 nanoparticles with a mean particle size of 4–6 nm were uniformly dispersed on the alkali-treated ZSM-5 zeolite. The bimetallic Pt8Co1/ZSM-5-AT catalyst exhibited an extraordinary COL selectivity of 65% at a >99% CAL conversion efficiency, which showed a much higher catalytic performance (including the activity and selectivity) than the monometallic Pt/ZSM-5-AT and Co/ZSM-5-AT catalysts in the selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL) using hydrogen as reducing agent. The high catalytic activity of the bimetallic catalyst was attributed to the higher electron density of Pt species and more acidic sites of the alkali-treated ZSM-5 zeolite support. The recovery test showed no obvious loss of its initial activity of the Pt8Co1/ZSM-5-AT catalyst for five times. [ABSTRACT FROM AUTHOR]

[Display omitted] The confinement effect known as efficient strategy to enhance the heterocatalytic activity and stability, but a clear view regarding the role of encapsulated overlayers is far from convincing at present, especially, the penetration of substrates with different size. Herein, the experimental evidence about the impacts of BN overlayers on hydrogenation is obtained over Co@BN/BN model catalysts with tuned thinness, in which BN overlayers encapsuled Co particles that dispersed on the defective BN supports, fabricating by the nitridizing of ball-milled BN microplates under NH 3 atmosphere. The thinness and crystallinity of BN shells was simply tuned by controlling the pyrolyzed temperature (600–900 °C). The cinnamaldehyde (CAL) selective hydrogenation is taken as probe reaction due to (1) both larger CAL and small H 2 molecule involved simultaneously, (2) the middle C C and terminal C O bonds all involved. Combined with structural analysis, the results demonstrate that small H 2 molecule can penetrate into the metal-cover interface through the defect sites, then inner Co core dissociate it to atomic H, and the hydrogenation mainly resulting from the spillover of H atoms which occurred on the BN surface. As a result, the thickest BN shells (∼3.4 nm) with ordered-layer-lattice significantly hindered the adsorption and activation of CAL, also the longest H spillover distance led to the lowest activity of Co@BN/BN-900. Instead, Co@BN/BN-600 with merely 2 ∼ 3 overlayers presented the most efficient and highly chemoselective hydrogenation activity. The ultrathin but turbostratic BN overlayers provide more migrating sites also shortened the H spillover distance effectively, and the more favorable C O hydrogenation was also achieved driven by the steric hindrance effect of thinner BN shells. These observations provide new insights towards understanding of confined effect on catalysis process through the accurate regulation of BN shells properties. [ABSTRACT FROM AUTHOR]

Pseudo-boehmite is prepared from industrial grade aluminum sulfate and sodium meta-aluminate coming from waste FCC catalysts. The effects of preparation technology， conditions and modification on crystal type， pore structure， surface acidity and morphology of pseudo-boehmites are investigated. The activity and selectivity of Pd/Al2O3 catalyst prepared by modified Al2O3 carrier and PdCl2 and Pd（acac）2 precursors for the selective hydrogenation of isoporone C==C are studied. The pseudo-boehmite with specific surface area of 413 m² /g， pore volume of 0. 84 cm3 /g and pore size of 6. 84 nm is obtained at the optimized preparation conditions. After the addition of ammonium carbonate and sodium silicate， the pore volume of pseudo-boehmite increases to 0. 98 cm³ /g and 1. 53 cm³/g， and the average pore size increases to 7. 70 nm and 12. 34 nm， respectively. The Pd/Al2O3 catalyst that is prepared using Al2O3 obtained by ammonium carbonate modifier as the carrier and PdCl2 as the precursor shows an activity of 98. 69% for the selective hydrogenation of isophorone C==C， more than 99% selectivity of 3,3, 5-trimethyl-cycloheeanon （TMCH), and high activity stability. [ABSTRACT FROM AUTHOR]

[Display omitted] The high selectivity in the hydrogenation reactions of α, β-unsaturated aldehydes is always a demanding task. Precious Pt-based catalysts play a pivotal role in selective catalytic hydrogenation of α, β-unsaturated aldehydes, but controlling the selectivity is still a great challenge. Herein, the Pt nanoparticles were encaged within the mesopores of amines (–NH 2) functionalized MOFs via polyol reduction method as an efficient approach to enhance the selectivity of desired carbonyls bond reduction. The as-prepared 3-Pt/MOF-NH 2 (x) catalysts retained the inherent properties of MOF-NH 2 (x) supports such as crystallinity, surface area, pore texture, and surface acidity. Remarkably, the amines modified MOFs supported Pt-based catalysts (3-Pt/MOF-NH2(x)) improved the selective hydrogenation of carbonyls (C O) bond in cinnamaldehyde (CAL) and Furfural (FFL) with a higher selectivity (≥80 %) under mild conditions as compared to other reported catalysts. The improved catalytic performance for the selective hydrogenation of carbonyls (C O) bond is credited to the nitrogen (N) heteroatom of the amines group existing in the skeleton of MOFs and somewhat to the steric effect induced by mesopores of MOFs. The N heteroatom not only helps in the high uniform dispersion and stabilization of small-sized Pt nanoparticles (≈2nm) but also adjust the electron movement (electronic density) via synergistic effect resulting from the N to the vacant d-orbital of active Pt nanoparticles confined within MOFs, leading to more new interfacial electrophilic and nucleophilic sites, which are beneficial for selective hydrogenation of C O bond. Besides, the steric effect induced by mesopores of MOFs, encaging Pt nanoparticles, can also enhance the selective adsorption of the C O bond to interact with the catalyst active sites, resulting in higher selective hydrogenation of C O bond. [ABSTRACT FROM AUTHOR]

The effect of nickel precursors and the temperature annealing to obtain intermetallic Ni3Sn2 alloy catalysts on its activity and selectivity in the selective hydrogenation of biomass-derived furfural (FFald) were investigated. Two types of nickel precursors (c.a., i) nickel metal (Ni°) derived from Raney®nickel and ii) nickel ion (Ni2+) derived from nickel chloride) were employed as the starting materials via hydrothermal at 423 K for 24 h followed by reduction with H2 at the elevated temperature of 573-873 K for 1.5 h. The physico-chemical properties of the intermetallic Ni3Sn2 were characterized by XRD, N2-, and H2-adsorption, ICP-AES, and NH3-TPD. The intermetallic Ni3Sn2 alloy catalysts, both bulk and supported, demonstrated high activity and selectivity towards hydrogenation of FFald. The activity and selectivity of γ-Al2O3 and AA-supported Ni3Sn2 alloy catalysts in the hydrogenation of FFald to furfuryl alcohol (FFalc) were maintained even after annealing at up to 873 K, but that of bulk Ni3Sn2 drastically dropped. Ni-Sn alloy catalysts which were obtained from Raney®Ni precursor showed more stable than that of nickel salts during hydrogenation of furfural to furfuryl alcohol. [ABSTRACT FROM AUTHOR]

The development of active, selective, and stable multicrystalline catalytic coatings on the inner surface of microcapillary reactors addresses environmental problems of fine organic synthesis, in particular by reducing the large quantities of reagents and byproducts. Thin-film nanosized bimetallic catalysts based on mesoporous pure titania and doped with zirconia, ceria, and zinc oxide, for use in microreactors, were developed, and the regularities of their formation were studied. The efficiency of PdZn/TixM1−xO2±y (M = Ce, Zr, Zn) in the hydrogenation of 2-methyl-3-butyn 2-ol was studied with an emphasis on the stability of the catalyst during the reaction. The catalytic parameters depend on the adsorption properties and activity of PdZn and Pd(0) active centers. Under reaction conditions, resistance to the decomposition of PdZn is a factor that affects the stability of the catalyst. The zinc-doped coating proved to be the most selective and stable in the reaction of selective hydrogenation of acetylenic alcohols in a microcapillary reactor. This coating retained a high selectivity of 98.2% during long-term testing up to 168 h. Modification of the morphology and electronic structure of the active component, by doping titania with Ce and Zr, is accompanied by a decrease in stability. [ABSTRACT FROM AUTHOR]

Development of the economic, environmentally friendly synthesis of amines from nitro compounds remains important and challenging. In this work, the graphene shell encapsulated none noble Ni-based catalysts were successfully designed and synthesized via an environmentally friendly method using H2O or EtOH as solvent. These fresh and recycling catalysts were characterized by X-ray diffraction and X-ray photoelectron spectroscopy. For the nitro compounds hydrogenation, Ni@C-600-H2O exhibits the best catalytic activity to achieve 100 mol/mol conversions of nitrobenzene and 99% selectivity of aniline under mild reaction conditions of 1.0 MPa H2 and 60 °C. Many halogen-substituted, olefin substituted nitro compounds and aliphatic nitro compounds were investigated and desired products were obtained in excellent selectivity. What is more, the catalyst had excellent stability and could be recycled 13 times without any significant loss in selectivity and activity. Furthermore, we also reported the methodology for tertiary amines synthesis using Ni-based catalyst via one-pot, cost-effective tandem combination reaction with nitrobenzene hydrogenation and amines N-methylation.

Developing a simple and mild one-step method for the preparation of bimetallic nanomaterials with both free-standing features and excellent catalytic performance is highly desirable but remains technically difficult. Herein, a facile liquid-liquid interface route is exploited to grow the wheat-like PdAg nanostructures at the interface of chloroform and water under mild conditions without the use of any surfactants and supports. To implement this scheme, Na 2 PdCl 4 and AgNO 3 as precursors are dissolved in aqueous phase and α-naphthol as reducing agent in chloroform phase to build up the interfacial reaction system. At 40°C, the PdAg nanowheats are orderly grown, fused and assembled by many newly generated nanoparticles at the interface region, which have uniform shapes with the length of about 340 nm and the diameter of about 45 nm, abundant defects and strong electronic interaction between Au and Pd, as well as free-standing features. In the hydrogenation reaction of 4-nitrobenzaldehyde, PdAg-1 nanowheats exhibit excellent catalytic activity, selectivity and durability. Within 60.0 min of reaction at 35°C under atmospheric pressure, 99.8 % conversion of 4-nitrobenzaldehyde and 99.5 % selectivity toward 4-aminobenzaldehyde can be realized. After 5 cycles, 99.4 % conversion of 4-nitrobenzaldehyde and 98.0 % selectivity toward 4-aminobenzaldehyde can be maintained. • The PdAg alloy nanowheats are one-pot prepared at CHCl3-H2O interface and 40 °C. • The synthesis is achieved without the uses of any surfactants, seeds or supports. • PdAg nanowheats have highly hydrogenation properties for 4-nitrobenzaldehyde. • 99.8 % conversion is achieved at 35°C within 60.0 min under atmospheric pressure. • Catalytic hydrogenation selectivity to 4-aminobenzaldehyde is as high as 99.5 %. [ABSTRACT FROM AUTHOR]