Hydrogenation Of 5-hydroxymethylfurfural Research Articles

Surfactant Directionally Assembled at the Electrode-Electrolyte Interface for Facilitating Electrocatalytic Aldehyde Hydrogenation.

Electrocatalytic hydrogenation of unsaturated aldehydes to unsaturated alcohols is a promising alternative to conventional thermal processes. Both the catalyst and electrolyte deeply impact the performance. Designing the electrode-electrolyte interface remains challenging due to its compositional and structural complexity. Here, we employ the electrocatalytic hydrogenation of 5-hydroxymethylfurfural (HMF) as a reaction model. The typical cationic surfactant, cetyltrimethylammonium bromide (CTAB), and its analogs are employed as electrolyte additives to tune the interfacial microenvironment, delivering high-efficiency hydrogenation of HMF and inhibition of the hydrogen evolution reaction (HER). The surfactants experience a conformational transformation from stochastic distribution to directional assembly under applied potential. This oriented arrangement hampers the transfer of water molecules to the interface and promotes the enrichment of reactants. In addition, near 100% 2,5-bis(hydroxymethyl)furan (BHMF) selectivity is achieved, and the faradaic efficiency (FE) of the BHMF is improved from 61% to 74% at -100 mA cm-2. Notably, the microenvironmental modulation strategy applies to a range of electrocatalytic hydrogenation reactions involving aldehyde substrates. This work paves the way for engineering advanced electrode-electrolyte interfaces and boosting unsaturated alcohol electrosynthesis efficiency.

Unraveling selectivity in non-noble metal-catalyzed hydrogenation of 5-hydroxymethylfurfural (HMF) through mechanistic insights

The development of heterogeneous catalysts for converting abundant biomass feedstocks to higher value products is one of the most challenges these days. 2,5-dihydroxymethylfuran (DHMF) and 2,5-dihydroxymethyltetrahydrofuran (DHMTHF), synthesized from HMF hydrogenation, serve as crucial precursors in various applications. Non-noble metal catalysts are particularly attractive for this reaction, given their affordability and impressive catalytic efficiency. This work unveils the origin of the unique selectivity over Ni and Cu through mechanistic investigation using density functional theory (DFT), thermodynamic and kinetic analyses. The results emphasize that temperature and solvent play a crucial role in altering the energetic stabilities of intermediates, thereby influencing the energetic span (δG), turnover frequency (TOF), and selectivity of the reaction. The theoretical results align well with experimental observations. At 373.15 K, the highest TOF values over Ni and Cu are predicted in the HMF-to-DHMTHF path (1.79 × 103h−1) and the HMF-to-DHMF path (4.01 × 105h−1), respectively, in gas phase—under low dielectric constant ε condition. In contrast, the highest TOF value for Ni is observed in the HMF-to-DHMF path under implicit water condition (ε = 78.4) at 298.15 K. Competitive DHMF desorption and further hydrogenation influence the reaction’s selectivity. These insightful fundamental findings reveal key descriptors essential for designing new heterogeneous catalysts or enhancing existing ones, with the aim of potentially impacting biomass upgrading and other hydrogenation reactions.

Insight into the catalytic mechanism of CuCeOx/C for the hydrogenation of 5-hydroxymethylfurfural to 2,5-bis(hydroxymethyl)furan

2,5-Bis(hydroxymethyl)furan (BHMF) is a diol with great potential for polyester monomer. Herein, an efficient CuCeOx/C was synthesized using carboxymethyl cellulose (CMC) as a sacrificial template for the catalytic hydrogenation of 5-hydroxymethylfurfural (HMF) to BHMF. Under the optimal conditions, the BHMF yield of over 98 % was obtained. The unique catalyst reactivity originated from the synergism of the rich oxygen vacancies (OV) and Cu2+/Cu0-species on the catalyst surface. The incorporation of CeOx as support strengthened the electrophilicity for the Cu2+-species, which was beneficial to the adsorption of the negative aldehyde groups in HMF. The Cu2+ and Cu0-species on the CuCeOx/C surface were responsible for adsorbing HMF and activating H2. The selective adsorption of the aldehyde group in HMF via the oxygen-terminal through a vertical or tilted configuration ensured the efficient hydrogenation of HMF to BHMF.

Noble-Metal-Free Carbon Encapsulated CoNi Alloy Catalyst for the Hydrogenation of 5-(Hydroxymethyl) Furfural to Tetrahydrofurandiol in Aqueous Media.

The selective hydrogenation of 5-(hydroxymethyl)furfural (HMF) into 2,5-bis-(hydroxymethyl)tetrahydrofuran (BHMTHF) in flow reactor using water as a green solvent, has been achieved on a non-noble metal catalyst based on monodispersed CoNi alloy nanoparticles covered by a thin carbon layer. The alloyed catalyst containing CoNi (molar ratio 1 : 1) was prepared in a one-step synthesis following a hydrothermal method. Total conversion of HMF with 91 % selectivity to BHMTHF was achieved. The reaction network has been stablished, in which the carbonyl group of HMF is first reduced to alcohol giving the 2,5-bis-(hydroxymethyl)furan (BHMF) with an apparent activation energy of 25 KJ/mol, and then the double bonds of the furan ring are hydrogenated (apparent Ea=31 KJ/mol). Formation of byproducts, mainly proceed from furan ring opening and ring rearrangement processes of BHMF, promoted by water. BHMTHF resulted a compound highly stable under reaction conditions. The fixed bed flow reactor was maintained operational for 65 h without observing any loss of catalytic activity and selectivity.

Electrocatalytic hydrogenation of 5-hydroxymethyfurfural reactions promoted by CuZn catalysts

Electrochemical hydrogenation of 5-hydroxymethylfurfural (HMF) is a particularly important and environmentally friendly route to achieve sustainable high-value chemicals and biomass-based fuels. Herein, electrocatalytic hydrogenation (ECH) reaction of HMF using CuZn catalysts prepared by electrochemical deposition method was declared. The electrochemical hydrogenation of HMF to 5-methyfurfuryl alcohol (MFA) in alkaline aqueous medium has an excellent yield and faraday efficiency, with a maximum of 0.086 mmol cm−2 h−1, which has not been reported before. The selectivity and efficiency of ECH reaction were affected by electrolyte pH. The results indicated that electrocatalytic hydrogenation were not simply related to the type of electrode catalyst, but also sensitive to electrolytes, which can give important guidance for electrocatalytic hydrogenation of biomass-based platform molecules.

CuCoMgAlOx Mixed Oxides as Selective Catalysts for the Hydrogenation of Furan Compounds

Single phase CuCoMgAl-layered hydroxides were obtained by making fine adjustment to their composition through changing the (Co + Cu)/Mg = 0.5; 1; 2; 3 and Co/Cu = 0.5; 1; 2 ratios. The rise of Co/Cu in systems contributed to the increase in their thermal stability. CuCoMgAl-catalysts showed high selectivity of carbonyl group hydrogenation in furfural and 5-hydroxymethylfurfural. In furfural hydrogenation, the selectivity to furfuryl alcohol was more than 99%, and in 5-hydroxymethylfurfural hydrogenation, the selectivity to 2,5-hydroxymethyl furfural was 95%. The surface of the samples with different Co/Cu after calcination and reduction was the same and had a «core-shell» structure (TEM). «Core» consisted of Cu and Co metallic particles. «Shell» consisted of CuCoMgAlOx mixed no-stoichiometric spinel oxides. There was no sintering or change in size of the metallic particles after the reaction. For the sample with Co/Cu = 1, their phase composition after reaction remained unchangeable. The increase of Co/Cu led to the formation of an X-ray amorphous phase after the reaction. This suggests the decrease in structural stability of this sample. The obtained results prove the prospects of using bimetallic CoCu-systems for hydrogenation of furan aldehydes, and opens up new directions for further research and improvement.

Facet effect on the reconstructed Cu-catalyzed electrochemical hydrogenation of 5-hydroxymethylfurfural (HMF) towards 2,5-bis(hydroxymethy)furan (BHMF)

The electrochemical hydrogenation of HMF to BHMF is an elegant alternative to the conventional thermocatalytic route for the production of high-value-added chemicals from biomass resources. In virtue of the wide potential window with promising Faradic efficiency (FE) towards BHMF, Cu-based electrode has been in the center of investigation. However, its structure–activity relationship remains ambiguous and its intrinsic catalytic activity is still unsatisfactory. In this work, we develop a two-step oxidation–reduction strategy to reconstruct the surface atom arrangement of the Cu foam (CF). By combination of multiple quasi-situ/in-situ techniques and density functional theory (DFT) calculation, the critical factor that governs the reaction is demonstrated to be facet effect of the metallic Cu crystal: Cu(110) facet accounts for the most favorable surface with enhanced chemisorption with reactants and selective production of BHMF, while Cu(100) facet might trigger the accumulation of the by-product 5,5′-bis(hydroxymethy)hydrofurion (BHH). With the optimized composition of the facets on the reconstructed Cu(OH)2-ER/CF, the performance could be noticeably enhanced with a BHMF FE of 92.3% and HMF conversion of 98.5% at a potential of −0.15 V versus reversible hydrogen electrode (vs. RHE) in 0.1 M KOH solution. This work sheds light on the incomplete mechanistic puzzle for Cu-catalyzed electrochemical hydrogenation of HMF to BHMF, and provides a theoretical foundation for further precise design of highly efficient catalytic electrodes.

Selective furanyl ring hydrogenation of 5-hydroxymethylfurfural at sub-ambient temperature via steric effect on decorated Pd surfaces

It is a great challenge to synthesize the medical intermediate 5-hydroxymethyltetrahydrofurfural (HMTHF) from selective hydrogenation of 5-hydroxymethylfurfural (HMF), as the branched CO group is usually preferentially hydrogenated over active metal, e.g. Pd sites. Herein, we designed a surface-decorated Pd@NSi@Al2O3 catalyst and achieved selective hydrogenation of HMF, yielding 83.5% HMTHF at sub-ambient temperature (5 °C). Combination of experiments and DFT calculations verify the steric effect caused by the decoration of Pd surfaces led to larger bond lengths between O or C in –CHO ligand of HMF and the closest surface Pd sites. The total activation barrier for the hydrogenation reactions on the –CHO group of HMF becomes larger from 0.60 eV on Pd(111) to 0.83 eV on the cramped Pd(111). As a result, CC groups in the furanyl ring was preferentially hydrogenated over the branched CO of HMF. Furthermore, hydrogen bonds between the hydroxymethyl of the adsorbed HMF and the amine groups on Pd surfaces promote the adsorption of HMF and significantly increase the catalytic activity. Notably, this catalyst is robust and readily applicable in the furanyl ring hydrogenation of furfural and 5-methylfurfural. Overall, a controllable surface decoration strategy has been delivered that tailoring an efficient catalyst for selective hydrogenation of aromatic aldehyde.

Fe-Ni bimetallic nanoparticles encapsulated into nanofibrous carbon microspheres as a catalytic nanoreactor for highly selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dihydroxymethylfuran or 2,5-dihydroxymethyltetrahydrofuran

BackgroundThe highly efficient conversion of renewable biomass-derived platform compounds to high value-added chemicals is one of the most promising solution to the current rapid consumption of fossil resources. MethodsNanofibrous and porous carbon microspheres (NPCMs) were developed from chitin biomass and used to encapsulate Fe-Ni bimetallic nanoparticles for the formation of a novel catalytic nanoreactor (Fe-Ni/NPCMs), which was then used for the selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-dihydroxymethylfuran (DHMF) or 2,5-dihydroxymethyltetrahydrofuran (DHMTHF). Significant findingsThe NPCMs consisted of N-doped carbon nanofibers with a high surface area. The Fe-Ni bimetallic nanoparticles were uniformly dispersed on the carbon nanofiber surfaces of the Fe-Ni/NPCMs, resulting in abundant catalytic sites and excellent catalytic performance. Importantly, the Fe-Ni/NPCMs showed highly-selective hydrogenation of HMF to DHMF or DHMTHF with high yields of 93.6% or 94.9% through simply modulating the reaction conditions. Increasing the zero valent iron (Fe0) content in the Fe-Ni/NPCMs significantly promoted the DHMTH selectivity from HMF hydrogenation. Moreover, the Fe-Ni/NPCMs presented high stability and recyclability, and thus they are applicable to other biomass conversions. Therefore, Fe-Ni/NPCMs have promising industrial application in the production of high value-added chemicals from biomass-derived feed-stocks.

Regulating the interfacial electronic coupling of PtNi/TiO2 via bond evolution for highly efficient hydrogenation of 5-hydroxymethylfurfural

Solar-driven photocatalytic hydrogenation of 5-hydroxymethylfurfural (HMF) in the aqueous solution to form 2,5-dihydroxymethylfuran (DHMF) is an environmentally friendly method to produce fine chemical products. Herein, we demonstrate that a bimetallic PtNi-decorated TiO2 photocatalyst (PtNi/TiO2) exhibits excellent catalytic activity for selective HMF hydrogenation. Specifically, compared with the low conversion of Pt/TiO2 (1.56%) and Ni/TiO2 (0%), an HMF conversion efficiency of 100% and a DHMF selectivity of 99.7% are achieved on PtNi/TiO2 under mild conditions. The detailed structure and in-situ characterizations first reveal the strong electronic coupling between PtNi alloy and TiO2, which not only effectively promotes charge migration but also undergoes the evolution of surface chemical bonds during the photocatalytic HMF process. Furthermore, the significantly enhanced η2-(C, O) aldehyde adsorption configuration of HMF molecules to form DHMF via the CH-O·immediate route is also evidenced. This work provides a new insight for designing and fabricating highly efficient photocatalysts for HMF selective hydrogenation.

Facile synthesis of the atomically dispersed hydrotalcite oxide supported copper catalysts for the selective hydrogenation of 5–hydroxymethylfurfural into 2,5-bis(hydroxymethyl)furan

The selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) using the atomically dispersed supported copper catalyst is investigated. The hydrotalcite oxide supported copper materials (Cu(x)HTO) are facilely prepared by coprecipitating metal precursors in a methanolic solution under a tuned pH. The surface characterization involving PXRD, TEM, H2/N2O-TPR, and XAS reveals unequivocal evidence for the presence of the atomically dispersed copper on HTO surface. XAS specifically indicates the formation of mononuclear copper species, and H2/N2O-TPR strongly supports the copper atoms of Cu(5)HTO are evenly distributed in 99% dispersion. Moreover, the reduced Cu(5)HTO (r-Cu(5)HTO) enables to completely hydrogenate HMF to BHMF under mild conditions, in comparison to the poor reactivity catalyzed by the hydrotalcite oxide supported copper nanoparticles (r-Cu(4)@HTO). The dramatic enhancement of HMF hydrogenation catalyzed by r-Cu(5)HTO can be attributed to the fine distribution of copper atoms which are situated homogeneously over HTO surface as well as chemically reactive for the carbonyl group.

Mechanistic Insight into Favorable Aldehyde Hydrogenation over Hydroxymethyl Hydrogenolysis in 5-Hydroxymethylfurfural by Formic Acid over Single-Atom Co-N3/C

Although the Co–N–C catalyst exhibits good catalytic performance toward the hydrogenation of 5-hydroxymethylfurfural (HMF) with formic acid (FA) as the H source, its catalytic mechansim is still unclear at the molecular level, including competitive hydrogenation of the aldehyde (−CHO) group and hydrogenolysis of the hydroxymethyl (−CH2OH) group. Here, a single-atom Co-N3/C surface was modeled as a Co–N–C catalyst with an armchair model of activated carbon support. Over Co-N3/C, the catalytic mechanism for the hydrogenation/hydrogenolysis of HMF with FA has been theoretically investigated in 1,4-dioxane solution at the GGA-PBE/DNP level. The hydrogenation product, i.e., 2,5-dihydroxymethylfuran (DHMF), should be predominant, whereas the hydrogenolysis products, i.e., 5-methylfurfuryl alcohol (5-MFA), 5-methylfurfural (5-MF), and 2,5-dimethylfuran (DMF), should be minor. The rate-determining steps are concerned with the cleavage of the C–H bond in the FA moiety through an intermolecular H-shift. For the crucial transition states, compared with the Co–C group in the hydrogenolysis of the −CH2OH group, the Co–O–C group in the hydrogenation of the −CHO group can more efficiently promote the cleavage of the C–H bond in the FA moiety, which stems from the electrophilic properties of aldehyde oxygen. Kinetically, Co-N3/C boosts the hydrogenation of the −CHO group to a −CH2OH group and selectively hampers the hydrogenolysis of the −CH2OH group to a −CH3 group.

Selective hydrogenation reactions of 5-hydroxymethylfurfural over Cu and Ni catalysts in water: Effect of Cu and Ni combination and the reagent purity

This work studies the catalytic properties of Cu and Ni catalysts, as well as the effect of Cu and Ni combination on the activity and selectivity during the aqueous phase hydrogenation of 5-hydroxymethylfurfural (HMF) in a batch reactor, at 60 °C under 30 bar H2. Catalysts with different Ni/Cu ratios (10 wt%) were synthesized over a high surface area graphite (HSAG). While Ni provides the bimetallic catalyst the capacity for hydrogenation of CO and CC groups, Cu contributes to suppress the hydrogenation of the furan ring, reaching a 99% of selectivity to the partial hydrogenated product, 2,5-di-hydroxymethylfuran (DHMF), over 5Cu5Ni/HSAG. The increase of reaction temperature (180 °C) conduced to the hydrolytic ring-opening and rearrangement of HMF. Under such reaction conditions, monometallic Ni afforded the highest yield towards the hydrogenative rearrangement product, 3-hydroxymethylcyclopentanone (81%). However, Cu and CuNi bimetallic catalysts were less reactive to the ring-rearrangement reaction and showed higher tendency to deactivation, especially when the HMF supplier contain sulfur impurities.

Boosting the catalytic performance of graphene-supported Pt nanoparticles via decorating with -SnBun: an efficient approach for aqueous hydrogenation of biomass-derived compounds.

The pursuit of new catalysts for the aqueous transformation of biomass-derived compounds under mild conditions is an active area of research. In the present work, the selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bishydroxymethylfuran (BHMF) was efficiently accomplished in water at 25 °C and 5 bar H2 pressure (after 1 h full conversion and 100% selectivity). For this, a novel nanocatalyst based on graphene-supported Pt NPs decorated with Sn-butyl fragments (-SnBun) has been used. More specifically, Pt NPs supported on reduced graphene oxide (rGO) were functionalized with different equivalents (0.2, 0.5, 0.8 and 1 equiv.) of tributyltin hydride (Bu3SnH) following a surface organometallic chemistry (SOMC) approach. The synthesized catalysts (Pt@rGO/Snx) were fully characterized by state-of-the-art techniques, confirming the presence of Sn-butyl fragments grafted on the platinum surface. The higher the amount of surface -SnBun, the higher the activity of the catalyst, reaching a maximum conversion with Pt@rGO/Sn0.8. Indeed, the latter has proven to be one of the most active catalysts reported to date for the aqueous hydrogenation of HMF to BHMF (estimated TOF = 666.7 h-1). Furthermore, Pt@rGO/Sn0.8 has been demonstrated to be an efficient catalyst for the reduction of other biomass-derived compounds in water, such as furfural, vanillin or levoglucosenone. Here, the catalytic activity is remarkably boosted by Sn-butyl fragments located on the platinum surface, giving a catalyst several times faster than non-functionalized Pt@rGO.

Selective hydroconversion of 5-hydroxymethylfurfural to 2,5-bis(hydroxymethyl)furan using carbon nanotubes-supported nickel catalysts

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 carbonnanotubes (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.

A Modular Co-assembly Strategy for Ordered Mesoporous Perovskite Oxides with Abundant Surface Active Sites.

The ordered mesoporous perovskite oxides with well-defined mesostrcture and versatile metal sites are attractive, but their successful synthesis faces challenges of complicated assembly dynamics and pore collapse in crystalline calcination. Here, we propose an energy balance concept to reveal interplay relationship in assembly process and realize regulation of porous structure for mesoporous perovskite oxides. A series of ordered mesoporous perovskite oxides with unique porous structure were prepared by a modular co-assembly method. Mesoporous La2 Zr2 O7 shows 94 % conversion and 99 % selectivity for hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan. Experiments reveal that rich Lewis acid sites, active Zr species, and favorable porous structure promote interaction between mesoporous La2 Zr2 O7 and HMF and reduce catalytic energy barrier. This work provides the insight into molecule co-assembly and developing multiple component ordered mesoporous materials.

A Modular Co‐assembly Strategy for Ordered Mesoporous Perovskite Oxides with Abundant Surface Active Sites

AbstractThe ordered mesoporous perovskite oxides with well‐defined mesostrcture and versatile metal sites are attractive, but their successful synthesis faces challenges of complicated assembly dynamics and pore collapse in crystalline calcination. Here, we propose an energy balance concept to reveal interplay relationship in assembly process and realize regulation of porous structure for mesoporous perovskite oxides. A series of ordered mesoporous perovskite oxides with unique porous structure were prepared by a modular co‐assembly method. Mesoporous La2Zr2O7 shows 94 % conversion and 99 % selectivity for hydrogenation of 5‐hydroxymethylfurfural (HMF) to 2,5‐bis(hydroxymethyl)furan. Experiments reveal that rich Lewis acid sites, active Zr species, and favorable porous structure promote interaction between mesoporous La2Zr2O7 and HMF and reduce catalytic energy barrier. This work provides the insight into molecule co‐assembly and developing multiple component ordered mesoporous materials.

Highly selective hydrogenation of 5-hydroxymethylfurfural to 2,5-bis(hydroxymethyl)furan over metal-oxide supported Pt catalysts: The role of basic sites

Catalytic hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) is an important reaction for biomass valorization. We report that metal oxides (including MgO, ZnO, SiO2 and TiO2) supported Pt catalysts show vastly different BHMF selectivity towards the hydrogenation of HMF. The basic metal oxide MgO supported Pt catalyst affords 99 % selectivity of BHMF, while the typical acidic metal oxide TiO2 supported Pt catalyst displays only 28 % selectivity of BHMF. HMF chemisorption on these catalysts show that the basic sites of metal oxide bonding to the CO group of HMF promote the BHMF selectivity, while the acidic sites of metal oxide favor the adsorption of CC group of HMF, which decreases the BHMF selectivity. It is proposed that the cooperation between basic sites and Pt atoms (activating H2) boosted the BHMF selectivity. Comprehensive studies including reactivity, recyclability, stability, solvent effect on the Pt/MgO catalyst were also carried out.

Selective Hydrogenation of 5-Hydroxymethylfurfural to 1-Hydroxy-2,5-hexanedione by Biochar-Supported Ru Catalysts.

The development of sustainable and efficient catalysts -namely Ru supported on activated biochars- is carried out for the selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 1-hydroxy-2,5-hexanedione (HHD). Activated biochars obtained from pyrolysis and steam-based physical activation of two different biomasses from animal (leather tannery waste; ALw ) and vegetal (hazelnut shells; AHSw ) origins show completely different chemical, textural, and morphological properties. Compared to ALw , after impregnation with 0.5 wt % Ru, AHSw , with inner micro-mesochannels and cavities and higher layer stacking disorder, leads to better trapping and anchoring of Ru nanoparticles on the catalyst and a suitable Ru single crystal dispersion. This leads to a highly active Ru/AHSw catalyst in the proposed reaction, giving more than 80 % selectivity to HHD and full HMF conversion at 100 °C with 30 bar H2 for 3 h. Ru/AHSw also shows promising performance compared to a commercial Ru/C catalyst.

Selective Hydrogenation of 5-Hydroxymethylfurfural to 2,5-Dimethylfuran Over Popcorn-Like Nitrogen-Doped Carbon-Confined CuCo Bimetallic Catalyst.

A new type of biomass-based liquid fuel, 2,5-dimethylfuran (DMF), has attracted significant attention owing to its unique physical properties and carbon neutrality. It can be obtained from the hydrogenation of 5-hydroxymethylfurfural (HMF), an important biomass platform compound. In this study, we developed a nitrogen-doped carbon-confined CuCo bimetallic catalyst with a popcorn-like structure for the selective hydrogenation of HMF with high efficiency and adequate stability. Under optimized conditions, 100% HMF conversion and 93.7% DMF selectivity were achieved. The structure of the catalyst was characterized using XRD, XPS, SEM, and TEM. It was observed that carbon spheres, which were covered by nitrogen-doped carbon nanotubes, uniformly formed, while metal particles were confined in the nitrogen-doped carbon nanotubes. The popcorn-like structure exhibited a larger surface area and provided more contact sites, while the confined metal particles were the main active sites. The synergistic effect between Cu and Co was beneficial for DMF selectivity.