Oxidation Of 5-hydroxymethylfurfural Research Articles

Carbon-vacancy engineering approach to g-C3N4 for selective 5-hydroxymethylfurfural oxidation coupled with H2O2 production

CN modified with carbon and nitrogen vacancies was obtained through calcination under different atmospheres, resulting in efficient visible-light-driven photocatalysts for the conversion of biomass-relevant alcohols into fine chemicals.

Optimization of 5-hydroxymethylfurfural oxidation via photo-enzymatic cascade process

Trametes versicolor's laccase (LacTV) was efficient catalyst in HMF oxidation to FDCA. Its use in an enzymatic and photocatalytic cascade process permitted a 40-fold increase in FDCA productivity compared to traditional enzymatic batch systems.

CuO-Ni(OH)2 heterostructure nanosheets: a high-performance electrocatalyst for 5-hydroxymethylfurfural oxidation.

CuO-Ni(OH)2 heterostructure nanosheets were designed for efficient electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furanedioic acid (FDCA). The CuO-Ni(OH)2 nanosheets exhibited impressive performance, achieving 100% HMF conversion, 99.8% FDCA yield, and 98.4% faradaic efficiency.

Enhanced surface reconstruction of V-doped Ni3N driven by strong OH adsorption to boost 5-hydroxymethylfurfural electrooxidation for energy-saving H2 production

The 5%V-Ni3N exhibits high efficiency for the 5-hydroxymethylfurfural oxidation reaction for boosting energy-saving H2 production. The doped V could strengthen the OH adsorption for enhancing the surface reconstruction to active (oxy)hydroxide sites.

Hydroxy and surface oxygen effects on 5-hydroxymethylfurfural oxidation to 2,5-furandicarboxylic acid on β-MnO2: DFT, microkinetic and experiment studies.

Manganese dioxide, β-MnO2, has shown potential in catalyzing the oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), a monomer of bioplastic polyethylene furanoate (PEF). Herein, the insight into the hydroxy (OH) and surface oxygen effects on the HMF-to-FDCA reaction over β-MnO2 is clarified through a comprehensive investigation using density functional theory (DFT) calculations, microkinetic modeling, and experiment. Theoretical analyses revealed that both active surface oxygen and OH species (from either base or solvent) facilitate C-H bond breaking and OH insertion, promoting the catalytic activity of β-MnO2. Microkinetic modeling demonstrated that the FFCA-to-FDCA and DFF-to-FFCA steps are the rate-limiting steps of the hydroxylated and non-hydroxylated surfaces, respectively. These theoretical results agree well with the experiment when water and dimethyl sulfoxide (DMSO) were used as solvents. In addition, the synthesized β-MnO2 catalyst showed high stability and activity, maintaining stable HMF conversion (≥99 mol%) and high FDCA yield (85-92 mol%) during continuous flow oxidation for 72 hours at pO2 of 1 MPa, 393 K and LHSV of 1 h-1. Thus, considering both hydroxy and surface oxygen species is a new strategy for enhancing the catalytic activity of Mn oxides and other metal oxide catalysts for the HMF-to-FDCA reaction.

Heterogeneous interface induced Co3O4-NiO catalyst for efficient electrocatalytic 5-Hydroxymethylfurfural oxidation

The electrooxidation of 5-hydroxymethylfurfural (HMF) provides an efficient and environmentally friendly approach to obtain high-value chemicals from biomass. In this study, porous nanocube framed Co3O4-NiO electrocatalysts with heterogeneous interface are constructed for efficient HMF oxidation reaction (HMFOR). The heterogeneous interface modulates the electronic properties of Co and Ni atoms, enhances the oxidation state of Ni species, which is favorable for the oxidation of HMF. Compared to pure Co3O4 and NiO, Co3O4-NiO exhibits a lower onset potential (1.22 V vs. RHE), higher FDCA yield (83.33 %) and Faraday efficiency (89.47 %). Furthermore, the results of open circuit potential (OCP), high-performance liquid chromatography (HPLC) product analysis and in-situ electrochemical impedance spectroscopy (EIS) demonstrate that the Co3O4-NiO heterogeneous interface effectively enhances the adsorption and transformation of organic molecules and OH– species, and facilitates the further oxidation of 5-formyl-2-furancarboxylic acid (FFCA) to 2,5-furandicarboxylic acid (FDCA), thus improving the performance of HMFOR. This work illustrates the effect of heterogeneous interface on Co3O4-NiO catalyst for HMFOR and provides a direction for the development of high-performance electrocatalysts for HMFOR.

Carbon-shell-encapsulated gold–palladium nanoreactors for highly efficient 5-hydroxymethylfurfural oxidation: Confinement and alloy effects study

Encapsulating noble metal nanoparticles in carbon nanoshells is an emerging and efficient way to enhance the activity and stability of noble metal species. A novel type of hollow rod-shaped carbon-shell-encapsulated gold–palladium (AuPd) alloy nanoreactor (AumPdn@CT) was designed and constructed. The Au2Pd1@C800 nanoreactor afforded a satisfactory 2,5-furandicarboxylic acid (FDCA) yield of 99.9 % from 5-hydroxymethylfurfural (HMF) oxidation using O2 as the oxidant in water. Remarkably, carbon-shell-encapsulated only 1.0 wt% AuPd alloy could offer an outstanding FDCA formation rate of 2003.6 mmol·g−1·h−1. Mechanistic studies demonstrated that the generated confinement and AuPd alloy species not only improved the adsorption capacity of the HMF substrate and the key intermediate 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), but also facilitated the adsorption and activation of molecular oxygen to generate oxygen active species of superoxide radicals. Constructing a carbon shell around AuPd alloy active sites provided effective physical protection for the metal core, thus enhancing the catalyst stability and reusability.

Aerobic Oxidation of 5-Hydroxymethylfurfural (HMF) in Aqueous Medium over Fe-Doped-Poly(heptazine imide) Photocatalysts: Unveiling the Bad Role of Hydroxyl Radical Generation on the Catalytic Performance.

5-hydroxymethylfurfural (HMF) oxidation in aqueous media using visible photocatalysis is a green and sustainable route for the valorization of lignocellulosic biomass derivatives. Several semiconductors have already been applied for this purpose; however, the use of Poly(heptazine imides), which has high crystallinity and a special cation exchange property that allows the replacement of the cation held between the layers of C3N4 structure by transition metal ions (TM), remains scarce. In this study, PHI(Na) was synthesized using a melamine/NaCl method and used as precursor to prepare metal (Fe, Co, Ni, or Cu)-doped PHI catalysts. The catalysts were tested for selective oxidation of HMF to 2,5-diformylfuran (DFF) in water and O2 atmosphere under blue LED radiation. The catalytic results revealed that the 0.1 wt% PHI(Fe) catalyst is the most efficient photocatalyst while higher Fe loading (1 and 2 wt%) favors the formation of Fe3+ clusters, which are responsible for the drop in HMF oxidation. Moreover, the 0.1 wt% PHI(Fe) photocatalyst has strong oxidative power due to its efficiency in H2O2 production, thus boosting the generation of nonselective hydroxyl radicals (●OH) via different pathways that can destroy HMF. We found that using 50 mM, the highest DFF production rate (393 μmol·h-1·g-1) was obtained in an aqueous medium under visible light radiation.

Strong p-d Orbital Hybridization on Bismuth Nanosheets for High Performing CO2 Electroreduction.

Single-atom alloys (SAAs) show great potential for a variety of electrocatalytic reactions. However, the atomic orbital hybridization effect of SAAs on the electrochemical reactions is unclear yet. Herein, the in situ confinement of vanadium/molybdenum/tungstenatoms on bismuth nanosheet is shown to create SAAs with rich grain boundaries, respectively. With the detailed analysis of microstructure and composition, the strong p-d orbital hybridization between bismuth and vanadium enables the exceptional electrocatalytic performance for carbon dioxide (CO2 ) reduction with the Faradaic efficiency nearly 100% for C1 products in a wide potential range from -0.6 to -1.4V, and a long-term electrolysis stability for 90h. In-depth in situ investigations with theoretical computations reveal that the electron delocalization toward vanadium atoms via the p-d orbital hybridization evokes the bismuth active centers for efficient CO2 activation via the σ-donation of O-to-Bi, thus reduces protonation energy barriers for formate production. With such fundamental understanding, SAA electrocatalyst is employed to fabricated the solar-driven electrolytic cell of CO2 reduction and 5-hydroxymethylfurfural oxidation, achieving an outstanding 2,5-furandicarboxylic acid yield of 90.5%. This study demonstrates a feasible strategy to rationally design advanced SAA electrocatalysts via the basic principles of p-d orbital hybridization.

Reaction kinetics of photoelectrochemical water and 5-hydroxymethylfurfural oxidation on rutile nanorod photoanode with Ge doping and core/shell structure

A high-performance TiO2/Ge-TiO2 nanorod photoanode, with the synergistic effect of Ge doping and core/shell structuring on promoting charge separation, was used in the photoelectrochemical H2 production system. The TiO2/Ge-TiO2 photoanode exhibited >90% hole transfer efficiency at 1.23 V vs. RHE for water oxidation. Moreover, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated hydroxymethylfurfural (HMF) oxidation was achieved on the TiO2 photoanodes for the first time. Notably, the kinetics of HMF oxidation were slower compared to water oxidation, resulting in a higher Faraday efficiency (FEHMF) corresponding to a lower hole transfer efficiency. The oxidation of HMF on the TiO2 photoanodes was found to predominantly follow the pathway dominated by 2,5-diformylfuran (DFF). The FEHMF displayed variation on the TiO2 photoanodes, with Ge doping leading to a decrease by enhancing surface hydrophilia. However, this decrease was effectively compensated for by the overlay of the TiO2 shell. Consequently, the TiO2/Ge-TiO2 photoanode achieved the highest HMF conversion rate, which can be attributed to the accelerated production and conversion of DFF. This work expands the application of TiO2 photoanodes on biomass conversion and sheds light on the pathway and kinetic characteristics of TEMPO-mediated HMF oxidation processes.

Partially Thiolated Aun (n = 25, 102) Clusters on Layered Double Hydroxides Anchored by Electrostatic Interactions: Size Effect on 5-Hydroxymethylfurfural Oxidation Catalysis

Partially Thiolated Au_<i>n</i> (<i>n</i> = 25, 102) Clusters on Layered Double Hydroxides Anchored by Electrostatic Interactions: Size Effect on 5-Hydroxymethylfurfural Oxidation Catalysis

Selective Oxidation of 5-Hydroxymethyl Furfural Coupled with H2 Production over Surface Sulfur Vacancy-Rich Zn3In2S6/Bi2MoO6 Heterojunction Photocatalyst.

The construction of heterojunctions and surface defects is a promising strategy for enhancing photocatalytic activity. A surface sulfur vacancy (VS)-rich Zn3In2S6/Bi2MoO6 heterojunction photocatalyst (ZIS-VS/BMO) was herein developed for the selective oxidation of biomass-derived 5-hydroxymethyl furfural (HMF) to value-added 2,5-diformylfuran (DFF) coupled with H2 production. The ZIS-VS/BMO heterojunction consisted of Bi2MoO6 (BMO) with preferentially exposed high-index (131) facets and VS-rich two-dimensional (2D) Zn3In2S6 (ZIS-VS) nanosheets with preferentially exposed high-index (102) facets. The directional transfer of light-driven electrons from BMO to ZIS-VS occurs in the heterojunction interface, as confirmed by an in situ irradiated XPS (ISI-XPS) measurement, which facilitates the electron-hole separation. The benefits of VS in activating HMF, suppressing overoxidation of DFF, and accelerating electron transport were disclosed by molecular simulation. ZIS-VS/BMO displays outstanding performance with a DFF yield of 74.1% and a DFF selectivity of 90%, as well as a rapid rate of H2 evolution. This research would help design highly efficient photocatalysts and develop a new technology for biomass resource utilization.

Self-Reconstruction of Sulfate-Terminated Copper Oxide Nanorods for Efficient and Stable 5-Hydroxymethylfurfural Electrooxidation.

The electrochemical 5-hydroxymethylfurfural oxidation reaction (HMFOR) has been regarded as a viable alternative to sustainable biomass valorization. However, the transformation of the catalysts under harsh electrooxidation conditions remains controversial. Herein, we confirm the self-construction of cuprous sulfide nanosheets (Cu2S NSs) into sulfate-terminated copper oxide nanorods (CuO-SO42- NRs) during the first-cycle of the HMFOR, which achieves a near-quantitative synthesis of 2,5-furandicarboxylic acid (FDCA) with a >99.9% yield and faradaic efficiency without deactivation in 15 successive cycles. Electrochemical impedance spectroscopies confirm that the surface SO42- effectively reduces the onset potential for HMFOR, while in situ Raman spectroscopies identify a reversible transformation from CuII-O to CuIII-OOH in HMFOR. Furthermore, density functional theory calculations reveal that the surface SO42- weakens the Cu-OH bonds in CuOOH to promote the rate-determining step of its coupling with the C atom in HMF-H* resulting from HMF hydrogenation, which synergistically enhances the catalytic activity of CuO-SO42- NRs toward HMF-to-FDCA conversion.

Solid redox equilibrium via d-band centers regulation in the MoS2/Ni3S2 heterojunction for efficient selective oxidation of 5-hydroxymethylfurfural

The 5-hydroxymethylfurfural electrocatalytic oxidation reaction (HMFOR), in coupling with the hydrogen evolution reaction (HER), can replace the kinetically slow anodic oxygen evolution reaction (OER) to produce high value oxides and hydrogen. However, the commonly employed Ni-based electrocatalyst exhibits an unsatisfied performance due to the existence of OER. Here, we design and synthesize the Ni3S2/MoS2/NiMoO4 catalyst for efficient and stable HMFOR reaction. Through the in situ Raman spectroscopy, we demonstrate that the NiIII–OOH formed during the surface reconstruction process is the real reactive species for HMFOR. Moreover, the density functional theory results show that the upward shift of d-band centers in the reconstructed NiOOH/MoS2 is beneficial for the HMF adsorption and guarantees the smooth progression of redox equilibrium reactions. As a result, the prepared electrocatalyst shows a good HMFOR electrocatalytic performance in terms of selectivity (99.2%), conversion (96.7%), and Faraday efficiency (96.5%).

Amorphous-crystalline heterostructure: Efficient catalyst for biomass oxidation coupled with hydrogen evolution

The development of catalysts with high activity, selectivity, and stability is critical for biomass upgrading coupled with hydrogen evolution. In this study, we present a simple method for fabricating crystalline-amorphous phase heterostructures using the etching effect of the acidic medium generated during cobalt salt hydrolysis, resulting in the formation of NiCo(OH)x-modified Ni/NiMoO4 nanosheets electrode (NiCo(OH)x/Ni/NiMoO4/NF). The nanosheets array formed during the synthesis process enlarges the surface area of the prepared catalyst, which facilitates the exposure of electrochemically active sites and improves mass transfer. Unexpectedly, the strong coupling interactions between the amorphous-crystalline heterointerface optimize the adsorption of reaction molecules and the corresponding charge transfer process, consequently boosting the catalytic activity for the 5-hydroxymethylfurfural oxidation reaction (HMFOR) and hydrogen evolution reaction (HER). Specifically, NiCo(OH)x/Ni/NiMoO4/NF catalyst requires only 1.34 V to obtain a current density of 10 mA cm−2 for HMFOR-coupled H2 evolution, and operates stably for 13 consecutive cycles with good product selectivity. This work thus provides insights into the design of efficient and robust catalysts for HMFOR-assisted H2 evolution.

High-yield synthesis of 2,5-Furandicarboxylic acid from fructose via a two-step strategy without 5-Hydroxymethylfurfural isolation using dioxane as a bridging solvent

2,5-Furandicarboxylic acid (FDCA) is a crucial bio-platform molecule for renewable polymers and fine chemicals. Here, a two-step method including fructose dehydration and 5-hydroxymethylfurfural (HMF) oxidation has been reported as an effective strategy to produce FDCA with high yield from fructose directly. In this method, for fructose dehydration over CH3SO3H, tetramethylammonium chloride (TmaCl) was first used as phase modifier and co-solvent in a H2O-dioxane biphasic-solvent system, affording HMF yield up to 90.6 % under mild condition (383 K) with relatively high fructose concentration (e.g. 5–10 wt %). Detailed 13C NMR studies verified the interaction between TmaCl and fructose, which significantly promoted the proportion of fructofuranoses and helped to improve the fructose dehydration activity and HMF yield. After dehydration step, more than 97.8 % of CH3SO3H were recovered in reaction phase for catalyst reuse, while the dioxane solution of extracted HMF was separated via simple phase separation. Followed by water commixing, this HMF dioxane solution (with the HMF concentration of 6.3 wt %) was directly oxidized over Ru/C (393 K, 1 MPa O2) to produce FDCA without HMF isolation and alkali addition, affording FDCA yield near 90 %. This study integrates the fructose dehydration and HMF oxidation rationally via dioxane as the bridging solvent to achieve high FDCA yield without complex HMF purification steps, and thus proposes an applicable model for high-efficient production of FDCA in practice.

Boosting The Electrochemical 5-Hydroxymethylfurfural Oxidation by Balancing The Competitive Adsorption of Organic And OH- Over Controllable Reconstructed Ni3 S2 /NiOx.

The electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) is a promising method for the efficient production of biomass-derived high-value-added chemicals. However, its practical application is limited by 1) low activity and selectivity caused by the competitive adsorption of HMF and OH- and 2) low operational stability caused by the uncontrollable reconstruction of the catalyst. To overcome these limitations, a series of Ni3 S2 /NiOx -n catalysts with controllable compositions and well-defined structures were synthesized using a novel in-situ controlled surface reconstruction strategy. The adsorption behavior of HMF and OH- could be continuously adjusted by varying the ratio of NiOx to Ni3 S2 on the catalysts surface, as indicated by in-situ characterizations, contact angle analysis and theoretical simulations. Owing to the balanced competitive adsorption of HMF and OH- , the optimized Ni3 S2 /NiOx -15 catalyst exhibited remarkable HMF electrocatalytic oxidation performance, with the current density reaching 366mA cm-2 at 1.5 VRHE and the Faradaic efficiency of the product, 2,5-furanedicarboxylic acid, reaching 98%. Moreover, Ni3 S2 /NiOx -15 exhibited excellent durability, with its activity and structure remaining stable for over 100h of operation. This study provides a new route for the design and construction of catalysts for value-added biomass conversion and offers new insights into enhancing catalytic performance by balancing competitive adsorption. This article is protected by copyright. All rights reserved.

Engineering a localized electrostatic environment to enhance hydroxyl activating for electrocatalytic biomass conversion

The 5-hydroxymethylfurfural electrocatalytic oxidation reaction (HMFOR) is a sustainable and efficient route for converting biomass platform molecules into high-value chemicals. The HMFOR process involves the simultaneous oxidation of hydroxyl and aldehyde groups. Optimizing the reaction pathways by modulating the adsorption behavior of 5-Hydroxymethylfurfural molecules toward a higher conversion rate is vital for achieving an efficient HMFOR. In this study, the HMFOR electrocatalytic performance of NiO was enhanced by regulating the surface microenvironment through the decoration of NiO nanosheets with polypyrrole (PPy). Operando Fourier transform infrared spectroscopy, density functional theory calculation, and electrochemical behavior characterizations demonstrated that electropositive PPy can optimize the adsorption behavior of electronegative hydroxyl groups and modulate the reaction pathway toward the formation of 2,5-diformylfuran intermediates. By modulating the local microenvironment, the designed NiO-PPy catalyst showed excellent HMFOR performance with a threefold increase in current density. This study emphasizes the significance of the surface microenvironment in modulating reaction pathways to achieve selective biomass electrocatalytic conversion.

Pd Loaded NiCo Hydroxides for Biomass Electrooxidation: Understanding the Synergistic Effect of Proton Deintercalation and Adsorption Kinetics.

The key issue in the 5-hydroxymethylfurfural oxidation reaction (HMFOR) is to understand the synergistic mechanism involving the protons deintercalation of catalyst and the adsorption of the substrate. In this study, a Pd/NiCo catalyst was fabricated by modifying Pd clusters onto a Co-doped Ni(OH)2 support, in which the introduction of Co induced lattice distortion and optimized the energy band structure of Ni sites, while the Pd clusters with an average size of 1.96 nm exhibited electronic interactions with NiCo support, resulting in electron transfer from Pd to Ni sites. The resulting Pd/NiCo exhibited low onset potential of 1.32 V and achieved a current density of 50 mA/cm2 at only 1.38 V. Compared to unmodified Ni(OH)2, the Pd/NiCo achieved an 8.3-fold increase in peak current density. DFT calculations and in-situ XAFS revealed that the Co sites affected the conformation and band structure of neighboring Ni sites through CoO6 octahedral distortion, reducing the proton deintercalation potential of Pd/NiCo and promoting the production of Ni3+-O active species accordingly. The involvement of Pd decreased the electronic transfer impedance, and thereby accelerated Ni3+-O formation. Moreover, the Pd clusters enhanced the adsorption of HMF through orbital hybridization, kinetically promoting the contact and reaction of HMF with Ni3+-O.

A novel route to synthesize 2,5-furandicarboxylic: Direct carboxylation of 2-furoic acid with formate

Furan-2,5-dicarboxylic acid (FDCA) is an important biomass-derived diacid, and it is the most promising substitute for terephthalic acid. The common method of FDCA usually involves 5-hydroxymethylfurfural oxidation. Edible fructose is often used as the feedstock of 5-hydroxymethylfurfural, and the oxidation step would generate undesirable impurities. Herein, FDCA was novelty synthesized by carboxylation of formate and 2-furoic acid (FA) derived from unedible-biomass. This route is potentially advantageous because it is simple to operate and does not require any additional additives. The reaction mechanism has been elucidated by density functional theory (DFT) calculations. In the carboxylation process, the C(sp2)-H bond of formate (HCOOM) undergoes cleavage, generating the carbon dioxide radical anion (CO2•−). Subsequently, CO2•− attacks the C5 of FA, forming the CC bond and ultimately yielding FDCA. The conversion of HCOOM to CO2•− is an effective way to achieve carboxylation reaction. The rate-determining step of the carboxylation reaction is the cleavage of the C(sp2)-H bond of HCOO− with activation barrier of 159.11 kJ⋅mol−1. The investigation would provide a new strategy for the mechanism of carboxylation reactions, and hold the potential to establish pathways for FDCA production.