HMF Conversion Research Articles

MOF Material-Derived Bimetallic Sulfide CoxNiyS for Electrocatalytic Oxidation of 5-Hydroxymethylfurfural.

The electrocatalytic conversion of biomass into high-value-added chemicals is one of the effective methods of green chemistry. Conventional metal catalysts have disadvantages, such as low atomic utilization and small surface areas. Catalyst materials derived from metal-organic frameworks (MOFs) have received much attention due to their unique physicochemical properties. Here, an MOF-derived non-precious metal CoxNiyS electrocatalyst was applied to the oxidation of biomass-derivative 5-hydroxymethylfurfural (HMF). The HMF oxidation reaction activities were modulated by regulating the content of Co and Ni bimetals, showing a volcano curve with an increasing proportion of Co. When the Co:Ni ratio was 2:1, the HMF conversion rate reached 84.5%, and the yield of the main product, 2,5-furandicarboxylic acid (FDCA), was 54%. The XPS results showed that the presence of high-valent nickel species after electrolysis, which further proved the existence and reactivity of NiOOH, as well as the synergistic effect of Co and Ni promoted the conversion of HMF. Increasing the content of Ni could increase the activity of HMF electrochemical oxidation, and increasing the content of Co could reduce the increase in the anodic current. This study has important significance for designing better HMF electrochemical catalysts in the future.

Single-atoms Ru/NiFe layered double hydroxide electrocatalyst: Efficient for oxidation of selective oxidation of 5-hydroxymethylfurfural and oxygen evolution reaction

The adsorption performance modulation of catalysts on reactants is effective for the improvement of catalytic oxidation reactions. Ru is beneficial for adsorption of products. Here, the single Ru atoms were supported on NiFe layered double hydroxide (LDH) (Ru0.3/NiFe) to enhance the adsorption capacity of catalyst using a two-step electrodeposition method. Ru0.3/NiFe was used in the oxygen evolution reaction (OER) and the selective oxidation of 5-hydroxymethylfurfural (HMFOR). Ru0.3/NiFe showed extremely low overpotential (243 mV at 10 mA cm-2) and excellent durability in OER. Ru0.3/NiFe exhibits excellent HMF conversion (99.43%), 2,5-furan dicarboxylic acid (FDCA) selectivity (99.24%) and yield (98.68%) in HMFOR. The possible HMFOR reaction pathway was further studied, revealing that the load of Ru enhances the path from HMF to DFF, thereby improving the yield of FDCA. Both the outcomes of experimental findings and density functional theory (DFT) calculations indicate that increasing the composition of Ru optimizes the adsorption energy of HMF compared to NiFe, allowing FeNiOOH to more efficiently capture protons and electrons in HMFOR.

Alkalization of acetylacetonates: A facile and versatile method to prepare Ni-based hydroxides for the electrochemical production of bio-based 2,5-furandicarboxylic acid

A facile and versatile synthesis method is required for the preparation of Ni-based hydroxides, which are efficient electrocatalysts for oxidation of 5-hydroxymethylfurfural (HMF) to high-value added chemical 2,5-furandicarboxylic acid (FDCA). Herein, a preparation strategy for Ni-based hydroxides is provided based on the alkalization of acetylacetonates. With carbon black as the support, ultrathin porous Ni(OH)2 nanosheets (∼1 nm in thickness) are obtained with HMF conversion and FDCA yield reaching ∼100% and 98.1%, respectively. With carbon felt or nickel foam as the substrate, the self-supporting Ni(OH)2 electrode can continuously operate in anion exchange membrane electrolyzer for up to 80 h with the content of FDCA in product between 80% and 100%. After the scale-up of preparation process, the performance of catalyst and electrode is maintained. Moreover, Ni-Co bimetallic hydroxide can be also prepared by this method, which presents enhanced activity for HMF oxidation at low electrode potentials.

Catalytic Conversion of 5-Hydroxymethylfurfural and Fructose to 5-Ethoxymethylfurfural over Sulfonated Biochar Catalysts

5-Hydroxymethylfurfural (HMF) is a key platform compound that can be produced by the dehydration of typical carbohydrates like glucose and fructose. Among the derivatives of HMF, 5-ethoxymethylfurfural (EMF) is the etherification product of HMF with ethanol. Owing to some advantages (i.e., high energy density), EMF has been regarded as a potential liquid fuel. Therefore, catalytic conversion of HMF and fructose to EMF is of significance, especially using heterogeneous catalysts. In this paper, we demonstrated the preparation of biomass-based catalysts for the synthesis of EMF from HMF and fructose. Some sulfonated biochar catalysts were prepared by the carbonization of biomass-based precursors at high temperature in N2, followed by the subsequent sulfonation process employing concentered H2SO4 as sulfonation reagent. The obtained catalysts were characterized by scanning electron microscope (SEM), Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), and element analysis. The catalytic conversion of HMF to EMF was carried out in ethanol, providing a 78% yield with complete conversion at 120 °C. The catalytic activity of the used catalyst showed slight decrease for the etherification of HMF. Moreover, the catalysts were effective for the direct conversion of fructose towards EMF in 64.9% yield. Copyright © 2023 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).

Catalytic pyrolysis of cellulose and hemicellulose: Investigation on furans selectivity with different zeolite structures at microporous scale

Furans, as high-value chemicals, are very important target products for catalytic pyrolysis of biomass. In this work, the comparative performance of several different zeolites (SAPO18, SAPO11, SAPO34, and SSZ13 with different Si/Al ratios) for catalytic pyrolysis of cellulose and hemicellulose to generate furan compounds was investigated. SSZ13 was firstly found to improve the selectivity of the catalytic conversion of cellulose and hemicellulose to furans with up to 51.83% and 70.03%, respectively. The high selectivity of SSZ-13 was attributed to its smaller crystal size and higher total acid. SAPO11 was found for the first time to have a positive effect on the conversion of 5-HMF to 5-MFF. Correlation analysis suggested that isomerization was the limiting step in converting the cellulose to furans, while dehydration may be the determining step for hemicellulose. GC-MS results indicated the compound in the inner surface after pyrolysis was dominated by polycyclic aromatics and no furans were detected, supporting the hypothesis that the furans were formed on the external surface of zeolite. The difference in mass transfer rates formed on the inner and outer surfaces of the microporous zeolites contributed to the generation and transfer of furans. Compared to complex multifunctional catalysts, simple zeolite structures may have more application potential.

Regulating the Electronic Structure of Ni Sites in Ni(OH)2 by Ce Doping and Cu(OH)2 Coupling to Boost 5-Hydroxymethylfurfural Oxidation Performance.

Biomass is a sustainable and renewable resource that can be converted into valuable chemicals, reducing the demand for fossil energy. 5-Hydroxymethylfurfural (HMF), as an important biomass platform molecule, can be converted to high-value-added 2,5-furandicarboxylic acid (FDCA) via a green and renewable electrocatalytic oxidation route under mild reaction conditions, but efficient electrocatalysts are still lacking. Herein, we rationally fabricate a novel self-supported electrocatalyst of core-shell-structured copper hydroxide nanowires@cerium-doped nickel hydroxide nanosheets composite nanowires on a copper mesh (CuH_NWs@Ce:NiH_NSs/Cu) for electrocatalytically oxidizing HMF to FDCA. The integrated configuration of composite nanowires with rich interstitial spaces between them facilitates fast mass/electron transfer, improved conductivity, and complete exposure of active sites. The doping of Ce ions in nickel hydroxide nanosheets (NiH_NSs) and the coupling of copper hydroxide nanowires (CuH_NWs) regulate the electronic structure of the Ni active sites and optimize the adsorption strength of the active sites to the reactant, meanwhile promoting the generation of strong oxidation agents of Ni3+ species, thereby resulting in improved electrocatalytic activity. Consequently, the optimal CuH_NWs@Ce:NiH_NSs/Cu electrocatalyst is able to achieve a HMF conversion of 98.5% with a FDCA yield of 97.9% and a Faradaic efficiency of 98.0% at a low constant potential of 1.45 V versus reversible hydrogen electrode. Meanwhile, no activity attenuation can be found after 15 successive cycling tests. Such electrocatalytic performance suppresses most of the reported Cu-based and Ni-based electrocatalysts. This work highlights the importance of structure and doping engineering strategies for the rational fabrication of high-performance electrocatalysts for biomass upgrading.

Laser Promoting Oxygen Vacancies Generation in Alloy via Mo for HMF Electrochemical Oxidation.

It is well known that nickel-based catalysts have high electrocatalytic activity for the 5-hydroxymethylfurfural oxidation reaction (HMFOR), and NiOOH is the main active component. However, the price of nickel and the catalyst's lifetime still need to be solved. In this work, NiOOH containing oxygen vacancies is formed on the surface of Ni alloy by UV laser (1J85-laser). X-ray absorption fine structure (XAFS) analyses indicate an interaction between Mo and Ni, which affects the coordination environment of Ni with oxygen. The chemical valence of Ni is between 0 and 2, indicating the generation of oxygen vacancies. Density functional theory (DFT) suggests that Mo can increase the defect energy and form more oxygen vacancies. In situ Raman electrochemical spectroscopy shows that Mo can promote the formation of NiOOH, thus enhancing the HMFOR activity. The 1J85-laser electrode shows a longer electrocatalytic lifetime than Ni-laser. After 15 cycles, the conversion of HMF is 95.92%.

Selective two-electron electrocatalytic conversion of 5-Hydroxymethylfurfural boosting hydrogen production under neutral condition over Co(OH)2-CeO2 catalyst

The coupling of electrocatalytic oxidation of biomass derivatives with hydrogen evolution reaction (HER) is a promising strategy to promote hydrogen production, but it is extremely challenging to control the mild electrocatalytic conversion of biomass to high value-added chemicals simultaneously. A Co(OH)2-CeO2 self-supported catalyst is constructed and used as anode for selective electrocatalytic conversion of biomass derivative 5-hydroxymethylfurfural (HMF) coupled with HER in two-chamber electrolysis system. The adjusting of pH and potential regulates the oxidation ability of hydroxyl and aldehyde groups, achieving selective two-electron electrocatalytic conversion of HMF to 2-furancarboxylic acid (HMFCA) with a selectivity of 89.4%. In situ Raman spectroscopy reveals that the evolution of Co multivalent active species at different electrolysis conditions is key to the selective oxidation of HMF. In addition, the hydrogen production coupled with selective electrocatalytic conversion of HMF is 4.1 times that of the water splitting system, revealing its potential in developing clean energy.

Exfoliated Layered Metal Oxide-Supported Ruthenium Catalysts for Base-Free Oxidation of 5-Hydroxymethylfurfural into a Renewable Bioplastic Precursor

2,5-Furandicarboxylic acid (FDCA) is a potential biopolymer precursor for polyethylene furanoate production. This study focused on synthesizing FDCA via catalytic oxidation of 5-hydroxymethylfurfural (HMF) over Ru-based catalysts supported on exfoliated MgAl-double oxides (LDO) for the first time in a homogeneous base-free system. Effects of the exfoliation solvent, preparation method, and Ru loading level on the physicochemical and catalytic properties of the resulting catalysts were investigated. The exfoliated LDO-supported Ru catalysts exhibited enhanced textural properties, RuOx dispersion, and basicity, resulting in better catalytic activity (at least 6 times higher FDCA yield) than conventional LDO-supported Ru catalysts in the conversion into FDCA. The Ru-based catalyst supported on an exfoliated LDO/carbon nanocomposite, Ru(3)/ESV-LDC, revealed the nearly complete HMF conversion (99.2%) at an FDCA selectivity of >98%. This was attributed to the synergistic effect derived from good RuOx dispersion, providing a high proportion of lattice oxygen for boosting surface oxygen mobility, and high basicity, in terms of both strength and number of basic sites. Moreover, Ru(3)/ESV-LDC exhibited good reusability without a significant loss of HMF conversion and FDCA yield, suggesting strong chemical robustness of RuOx species and a stable interaction between the active metal and support.

Palygorskite-supported ruthenium catalysts for the efficient selective oxidation of 5-hydroxymethylfurfural to 2, 5-diformylfuran

The oxidation of 5-hydroxymethylfurfural (HMF) to 2, 5-diformylfuran (DFF) is an important reaction for the conversion of renewable biomass into feedstock chemicals. In this work, palygorskite (Pal)-supported ruthenium (Ru) catalysts were developed for the efficient selective oxidation of HMF to DFF. Using natural clay mineral palygorskite as the support enabled the immobilization and dispersion of Ru nanoparticles. A 100% HMF conversion, 98% DFF yield, and 98% DFF selectivity were obtained over Ru(III)/Pal catalyst after 4.5 h under the optimal reaction conditions at 110 °C and 10 bar of O2 in toluene. Ru nanoparticles and palygorskite synergistically achieve the excellent catalytic performance of the catalyst. The Ru metal active sites facilitate the activation of the reactants or intermediates, accelerating the formation of DFF. Furthermore, due to their different particle sizes and Ru species, the Ru(III)/Pal catalyst exhibits higher catalytic activity than the Ru(0)/Pal catalyst for the oxidation of HMF to DFF. The palygorskite-enhanced dispersion effect on Ru nanoparticles augments the catalytic activity. Moreover, the palygorskite-supported Ru catalyst showed good stability and was reused for at least five times consecutive cycles without significant loss of its catalytic activity.

Cu2 P7 -CoP Heterostructure Nanosheets Enable High-Performance of 5-Hydroxymethylfurfural Electrooxidation.

Electrooxidation of 5-hydroxymethylfural (HMF) into 2,5-furandicarboxylicacid (FDCA) has been regarded as a promising sustainable approach to achieve value-added chemicals. However, it is still impeded by the unsatisfactory performance of electrocatalysts. Here, Cu2 P7 -CoP heterostructure nanosheets were reported to enable powerful HMF electrooxidation. The Cu2 P7 -CoP heterostructure nanosheets were fabricated by microwave-assisted deep eutectic solvent (DES) approach, along with subsequent phosphiding. The Cu2 P7 -CoP heterostructure nanosheets enabled a superb 100 % HMF conversion at 1.43 V (vs. RHE) with 98.8 % FDCA yield and 98 % Faradaic efficiency (FE), demonstrating its promising application in HMF electrooxidation. X-ray photoelectron spectroscopy (XPS) analysis, open-circuit potential (OCP) approach and density functional theory (DFT) calculation uncovered that the electron transfer and redistribution between Cu2 P7 and CoP improved the adsorption capacity of HMF and modulated the catalytic performance. This study not only offered a powerful electrocatalyst for HMF electrooxidation, but also provided a conceptually new strategy for the heterostructure catalyst design.

Design and Synthesis of Porous Organic Polymers: Promising Catalysts for Lignocellulose Conversion to 5-Hydroxymethylfurfural and Derivates.

In the face of the current energy and environmental problems, the full use of biomass resources instead of fossil energy to produce a series of high-value chemicals has great application prospects. 5-hydroxymethylfurfural (HMF), which can be synthesized from lignocellulose as a raw material, is an important biological platform molecule. Its preparation and the catalytic oxidation of subsequent products have important research significance and practical value. In the actual production process, porous organic polymer (POP) catalysts are highly suitable for biomass catalytic conversion due to their high efficiency, low cost, good designability, and environmentally friendly features. Here, we briefly describe the application of various types of POPs (including COFs, PAFs, HCPs, and CMPs) in the preparation and catalytic conversion of HMF from lignocellulosic biomass and analyze the influence of the structural properties of catalysts on the catalytic performance. Finally, we summarize some challenges that POPs catalysts face in biomass catalytic conversion and prospect the important research directions in the future. This review provides valuable references for the efficient conversion of biomass resources into high-value chemicals in practical applications.

Microwave-Assisted Catalytic Conversion of 5-HMF for Biofuel Additives by Molybdophosphoric Acid Encapsulated KCC-1

In this work, the microwave-assisted reaction of 5-hydroxymethylfurfural (5-HMF) into valuable ether and acylated production formation was investigated with the help of molybdophosphoric acid encapsulated dendritic fibrous silica (KCC-1) as a catalyst. XRD, N2 adsorption-desorption, SEM, FT-IR, NH3-TPD, and TEM were used to analyze the physicochemical and structural properties of the synthesized catalysts. The microwave etherification of 5-HMF with ethanol was tested using synthesized catalysts. The effects of the reaction temperature, reaction time, catalytic amount, and microwave power were investigated. The resulting MPA-KCC-1 and IMPA-KCC-1 catalysts demonstrated excellent activity for the etherification of 5-HMF with ethanol, producing 5-(hydroxymethyl) furfural diethyl acetal (HMFDEA) and 5-(ethoxymethyl)furfural diethyl acetal (EMFDEA) products selectively. The significant advantages of the work are the selective production of EMFDEA at 82%, the catalyst can be easily removed via filtration, and the catalyst activity remains nearly intact even after five reaction cycles.

Liquid flow fuel cell with an electrodeposition-modified nickel foam anode for efficient oxidation of 5-hydroxymethylfurfural to produce 2, 5-furandicarboxylic acid with co-generation of electricity

Liquid flow fuel cells were developed as reactors for efficient conversion of 5-hydroxymethylfurfural (HMF) to 2, 5-furandicarboxylic acid (FDCA) at room temperature with co-generation of electricity. Electrodeposition modification of nickel foam (NF) with CoSO4 and NaH2PO2 (Co-P@NF anode) was found to significantly increase HMF oxidation efficiency, due to the reduction of polarization resistance of NF and increased electrochemical active area. However, the active species of Co-P@NF anode for HMF oxidation actually was NiOOH rather than cobalt. By using (VO2)2SO4 as a cathodic electron carrier, peak power density of 38.9 mW/cm2 at room temperature was obtained with 100% HMF conversion and 89.0–93.4% FDCA yield. FDCA concentration reached 81.8 g/L with 90% total yield after feeding HMF for six batches. Therefore, efficient production of FDCA was achieved under mild conditions with oxygen (air) as the final oxidant via the electron transport chains constructed by active nickel species and cathode electron carriers.

Electronic Modulation Induced by Ni-VN Heterojunction Reinforces Electrolytic Hydrogen Evolution Coupled with Biomass Upgrade.

The renewable electricity-driven hydrogen evolution reaction (HER) coupled with biomass oxidation is a powerful avenue to maximize the energy efficiency and economic feedback, but challenging. Herein, porous Ni-VN heterojunction nanosheets on nickel foam (Ni-VN/NF) are constructed as a robust electrocatalyst to simultaneously catalyze HER and 5-hydroxymethylfurfural electrooxidation reaction (HMF EOR). Benefiting from the surface reconstruction of Ni-VN heterojunction during the oxidation process, the derived NiOOH-VN/NF energetically catalyzes HMF into 2,5-furandicarboxylic acid (FDCA), yielding the high HMF conversion (>99%), FDCA yield (99%), and Faradaic efficiency (>98%) at the lower oxidation potential along with the superior cycling stability. Ni-VN/NF is also surperactive for HER, exhibiting an onset potential of ≈0mV and Tafel slope of 45mV dec-1 . The integrated Ni-VN/NF||Ni-VN/NF configuration delivers a compelling cell voltage of 1.426V at 10mA cm-2 for the H2 O-HMF paired electrolysis, about 100mV lower than that for water splitting. Theoretically, for Ni-VN/NF, the superiority in HMF EOR and HER is mainly dominated by the local electronic distribution at the heterogenous interface, which accelerates the charge transfer and optimize the adsorption of reactants/intermediates by modulating the d-band center, therefore being an advisable thermodynamic and kinetic process.

NiCo alloy nanoparticles anchored on mesoporous Mo2N nanosheets as efficient catalysts for 5-hydroxymethylfurfural electrooxidation and hydrogen generation

Construction of highly active and stable bifunctional catalysts for 5-hydroxymethylfurfural oxidation reaction (HMFOR) and hydrogen evolution reaction (HER) is meaningful but remains a challenge. Herein, the NiCo–Mo2N heterostructure nanosheets catalyst with excellent HMFOR/HER performance is obtained by a simple hydrothermal and calcination method. The heterogeneous interface between NiCo and Mo2N induces electron redistribution, regulating the electronic structure of the catalyst and thus optimizing the adsorption/desorption behavior of HMFOR/HER intermediates. Consequently, NiCo–Mo2N/NF exhibits superior catalytic activity with a potential of 1.14 VRHE/−17 mVRHE (HMFOR/HER) at ±10 mA cm−2, and the HMF conversion rate, FDCA yield, and Faradaic efficiency (FE) are ∼100%, 99.98%, and 98.65%, respectively. Besides, it only requires a low voltage of 1.36 V to achieve 100 mA cm−2 for HMFOR-assisted H2 production. This study provides a strategy for the development of efficient bifunctional catalysts for sustainable production of high value-added products and hydrogen.

Lead-Free Perovskite Cs2 SnBr6 /rGO Composite for Photocatalytic Selective Oxidation of 5-Hydroxymethylfurfural to 2,5-Diformylfuran.

Severe poisonousness and prolonged instability existing in organic-inorganic lead-based perovskite are two matters seriously hindering its potential future application in photocatalysis. Therefore, it is particularly important to explore ecology-friendly, air-stable and highly active metal-halide perovskites. Herein, a new and stable lead-free perovskite Cs2 SnBr6 decorated with reduced graphene oxide (rGO), is synthesized and employed in the photocatalytic organic conversion. The as-prepared Cs2 SnBr6 is ultrastable, exhibiting no clear changes after being placed in the air for six months. The Cs2 SnBr6 /rGO composite shows excellent photocatalytic activity in photo-driven-oxidation of 5-hydroxymethylfurfural (HMF) to high value enclosed 2,5-diformylfuran (DFF), achieving>99.5 % conversion of HMF and 88 % DFF selectivity in the presence of green oxidant O2 . Comprehensive characterizations disclose a multistep reaction mechanism, demonstrating that the molecular oxygen, photogenerated carriers, ⋅O2 - and 1 O2 altogether synergistically participate in the effective photo-driven conversion of HMF to DFF. This work expands the material gallery towards selective organic conversion and environmentally friendly perovskite options for photocatalytic application.

Mild and selective catalytic oxidation of 5-HMF to 2,5-FDCA over metal loaded biomass derived graphene oxide using hydrogen peroxide in aqueous media

Biomass-derived graphene oxide-supported metal catalysts (Ru@S-GO, Pd@ S-GO, and Pd/Ru@ S-GO) were produced in a tube furnace with a metal loading of 1 weight percent. All the synthesised nano catalysts were well characterised by XRD, FESEM-EDS, ICP-OES, XPS and FTIR, and applied for the oxidation of 5-hydroxymethylfurfural (5-HMF) to 2,5-furan dicarboxylic acid (FDCA). Hydrogen peroxide was utilized as the liquid oxidant due to its reduced mass transfer resistance. 5-HMF used in this study was also obtained from biomass. All the operational parameters, such as temperature of the reaction, amount of oxidant, base concentration, and catalyst loading were optimized using Response surface methodology (RSM) based on central composite design (CCD). Ru@S-GO was found to have greater activity and selectivity towards FDCA under benign reaction conditions, and complete conversion of 5-HMF to 2,5-FDCA was accomplished (98.8% yield) over 5 hours of reaction time in an aqueous medium with a lower catalyst loading and reduced metal content.

Carbon Nanotubes Deposited on Mordenite Zeolite/NiAl-Layered Double Hydroxide Composites as Electrocatalysts for 2,5-Furandicarboxylic Acid Production from 5-Hydroxymethylfurfural

The nanostructured free-standing NiAl-MOR-CNTs electrocatalysts containing carbon nanotubes (CNTs) deposited on mordenite (MOR) zeolite/NiAl-layered double hydroxide (NiAl-LDH) have been successfully fabricated. Initially, the core-shell NiAl-LDH-MOR with hierarchical structures was observed via an aqueous miscible organic solvent treatment process to deposit nanosized NiAl-LDH homogeneously on a zeolite surface. The synthesized NiAl-LDH-MOR composites were calcined to produce highly dispersed metal oxides catalyzing the CNTs formation via chemical vapor deposition using bioethanol as a feedstock, eventually producing the NiAl-MOR-CNTs composites. To illustrate the beneficial aspect of the prepared composite, they were mixed with Nafion as a binder and pressed into circular pellets used as free-standing electrodes for electrochemical oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), an important renewable monomer of bioplastic. The prepared free-standing electrodes exhibited an excellent catalytic performance of 100% conversion of HMF with a high selectivity of FDCA up to 92% under ambient conditions. Moreover, the synthesized electrocatalysts can be recycled even after several consecutive cycles without any loss of catalytic activity, confirming a high stability of the synthesized electrodes. This work illustrates the design of electrocatalysts by using conductive CNTs grown on highly dispersed metal active sites on zeolite/LDH composites without using commercial conductive supports such as nickel foam or carbon fiber paper.

Synergistic catalysis on atomic Ru-doped manganese oxide for aerobic oxidation of biomass-derived 5-hydroxymethylfurfural

Catalytic oxidation of biomass derived 5-Hydroxymethylfurfural (HMF) feedstock is a promising route to produce value-added chemicals 2, 5-diformylfuran (DFF). Here, we find that incorporating monatomic Ru into the crystalline lattice of α-MnO2 can trigger synergetic catalysis for aerobic oxidation of HMF. Ru species can not only act as active sites for HMF conversion, but also activate surface oxygen species by creating rich oxygen vacancies on the α-MnO2. As result, such catalyst delivers much higher DFF productivity than that of Ru located in the tunnel of support (110 °C, 1.5 MPa, 1 h) and state-of-the-art Ru-based catalysts. Furthermore, the direct conversion of fructose into DFF was realized by combination of Amberlyst-15 and Ru-MnO2 HT catalyst in one-pot via two-step. Characterization and kinetic results indicated that atomically dispersed Ru hosted in the crystalline lattice of support created abundant oxygen vacancies and thus weakened the Mn-O bond, resulting in facile lattice oxygen activation.