Search Results (181)

Efficient conversion of biomass-based platform molecules into high-value derivatives is recognized as one formidable challenge in biomass upgrading. In this work, a one-pot deep eutectic solvents-assisted solvothermal method was developed for the modification of the commercial Pt/C catalysts by introducing a secondary metal (M = Sn, Bi, Ge, Sb, Pb). The structural and electronic properties of the catalysts were precisely tuned. Among the screened metals, the addition of Sn yielded the most significant improvement in catalytic activity. The optimized PtSn_0.5/C-140 catalyst achieved superior furfural (FAL) conversion and furfuryl alcohol (FOL) selectivity under mild conditions (20 °C, 2 MPa H₂). Comprehensive characterizations, including XRD, HRTEM, XPS, and H₂-TPD, confirmed the formation of Pt-Sn solid-solution phase. Furthermore, Characterization and reaction results revealed that the electronic and geometric effects induced by Sn modulated Pt active sites, significantly enhancing the adsorption of the active H species. Additionally, the SnO_x species adjacent to the Pt-Sn sites served as hydrogen spillover acceptors, further accelerating the hydrogenation process. The synergy between the Pt-Sn solid-solution phase and SnO_x species is identified as the origin of the superior performance at room temperature. These findings provide a new strategy for the design of high-performance biomass conversion catalysts by upgrading commercial noble metal catalysts. Full article

Furfural (FAL), an important biomass-derived platform molecule, plays a vital role in bridging biorefineries and the production of high-value chemicals through its selective hydrogenation to furfuryl alcohol (FOL). In this work, a series of Cu-based bimetallic catalysts (Cu₅Ni_x/SiO₂) were prepared by a simple impregnation method and exhibited outstanding catalytic performance for the hydrogenation of furfural under the mild conditions. When the loading of Ni was 2 wt%, the optimal catalytic activity was obtained at 150 °C and 1 MPa H₂, achieving a furfural conversion of 97.3%. This catalyst also showed excellent stability, maintaining high activity and selectivity toward FOL after five consecutive reaction cycles. Structural characterizations using X-ray diffraction (XRD), Hydrogen temperature-programmed reduction (H₂-TPR), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) revealed strong electronic interactions between Cu and Ni species. The introduction of Ni promoted the reduction of Ni²⁺ and improved the dispersion of Cu, which in turn increased the number of accessible active sites and facilitated the hydrogenation process. This synergistic effect between Cu and Ni provides an efficient and low-cost strategy for the selective hydrogenation of biomass-derived furfural to high-valued chemicals. Full article

Cyclopentadiene is an important intermediate that is widely used in the production of useful chemicals, high-density aviation fuels and polymers. Conventional technologies for the production of cyclopentadiene from fossil energies suffer from low yield and selectivity. Therefore, the selective production of cyclopentadiene from renewable biomass is highly expected. In this work, a series of metal phosphates were found to be effective solid acid catalysts for the selective synthesis of cyclopentadiene from the dehydration of 1,3-cyclopentanediol, a platform compound that can be obtained from the aqueous phase rearrangement of furfuryl alcohol followed by hydrogenation. Among the investigated catalysts, lanthanum phosphate (LaP) exhibited the best performance. Over it, 100% 1,3-cyclopentanediol conversion and higher than 90% carbon yield of cyclopentadiene were achieved at 473 K under atmospheric pressure. Based on the results of characterization, the excellent performance of LaP catalyst can be rationalized by its higher amount of acid sites and average pore size. Full article

The catalytic synthesis of 1,2-pentanediol from biomass-derived feedstocks is of remarkable significance for addressing current environmental challenges and energy crises. In this paper, a series of Pt-based catalysts were prepared and evaluated in the hydrogenolysis of furfuryl alcohol. The 5Pt0.5Y/MgO provided a 1,2-pentanediol yield of 68.9% and a tetrahydrofurfuryl alcohol yield of 19.8% with 98.1% conversion of furfuryl alcohol, at 200 °C and 2 MPa H₂ for 10 h. The promotional effect of yttrium on the catalytic performance was investigated through catalytic reaction and comprehensive characterization. It was found that the reducibility of Pt species was suppressed by the introduction of Y species, resulting in reduced activity compared to the 5Pt/MgO catalyst. However, the addition of Y notably shifted the reaction pathway towards 1,2-pentanediol formation at the expense of tetrahydrofurfuryl alcohol selectivity. This increase in 1,2-pentanediol selectivity was attributed to a higher concentration of medium-strength basic sites on the Y-modified Pt catalyst. Furthermore, the strong interaction between Y₂O₃, Pt particles, and the MgO support led to high Pt dispersion and stability on the MgO surface, consequently yielding satisfactory recyclability. Full article

With the rapid industrialization, excessive reliance on fossil fuels has resulted in energy crises and environmental pollution, driving the search for sustainable alternatives. Biomass-derived resources have emerged as promising candidates to replace fossil-based feedstocks. Among these, furfural (FF) serves as a key platform molecule that can be catalytically hydrogenated to various high-value chemicals, with furfuryl alcohol (FA) representing one of the most valuable products. Currently, Cr-based catalysts remain predominant for the selective hydrogenation of FF to FA. However, the severe environmental toxicity of Cr necessitates urgent development of alternative Cr-free catalytic systems. This study systematically reviews recent advances in FF hydrogenation to FA, providing an in-depth discussion of reaction mechanisms, including adsorption configurations, solvent effects, and side reactions, as well as a comprehensive analysis of structure–activity relationships, involving active metal, support, promoter, and preparation methods. Furthermore, we evaluate the application of the advanced characterization techniques for monitoring the reaction processes. Finally, we propose the future research directions: (1) designing efficient and stable non-noble metal catalysts and (2) elucidating reaction mechanisms via the combined in situ characterization and theoretical calculations. These efforts would facilitate the academic understanding and industrial implementation of the FF-to-FA conversion process. Full article

Wood modification using biopolymers has emerged as a sustainable alternative to conventional chemical treatments, enhancing wood’s durability, moisture resistance, and mechanical properties while reducing environmental impact. This review provides a comprehensive overview of the latest advancements in biopolymer-based wood modification, focusing on commonly used biopolymers such as furfuryl alcohol, polylactic acid, caprolactone, polybutylene adipate terephthalate, polybutylene succinate, zein, lignin, tannin, chitosan, alginate, gums, fatty acids, rosin, and sorbitol + citric acid. Future perspectives highlight the need for interdisciplinary collaboration between academia, research institutions, and industry to accelerate innovation and commercialization. This review aims to provide valuable insights for researchers and industry professionals working toward the development of high-performance, eco-friendly modified wood products. Full article

The growing need for sustainable and resource-efficient materials increasingly promotes the use of block-glued laminated timber (glulam) in buildings and civil structures such as bridges. While timber is renewable and sustainable, the formaldehyde-based adhesives commonly used in glulam raise environmental and health concerns. This study addresses this gap by presenting one of the first combined life cycle assessment (LCA) and life cycle cost (LCC) analyses of bio-based versus synthetic adhesives for block-glued glulam. A pedestrian bridge in Zwolle, the Netherlands, serves as a case study. Three synthetic adhesives—melamine-urea formaldehyde (MUF), phenol resorcinol formaldehyde (PRF), and phenol formaldehyde (PF)—and two bio-based alternatives—lignin phenol glyoxal (LPG) and tannin-furfuryl alcohol formaldehyde (TFF)—are analyzed. The LCA covers raw material sourcing, transport, and end-of-life scenarios, with impacts assessed in accordance with EN 15804+A2 using Earthster and the Ecoinvent v3.11 database. The proposed method integrates environmental and economic assessments, with results presented both per kilogram of adhesive and per cubic meter of glulam to ensure comparability. Results show that synthetic adhesives have higher environmental impacts than bio-based adhesives: the carbon footprint of 1 kg of adhesive averages 0.60 kg CO₂-eq for bio-based adhesives and 2.01 kg CO₂-eq for synthetic adhesives. LCC are similar across adhesives, averaging EUR 400 per m³ of glulam. These findings suggest that bio-based adhesives can compete environmentally and economically, but their limited availability and uncertain long-term performance remain barriers. Overall, the study highlights trade-offs between sustainability and structural reliability and provides guidance for sustainable adhesive selection in timber engineering. Full article

The aim of the work was to develop a highly effective catalyst for the conversion of furfural into furfuryl alcohol through catalytic transfer hydrogenation, which is an important process for converting biomass-derived compounds into valuable chemicals. A highly mesoporous silica was modified with various zirconium and aluminium precursors to obtain Lewis acid centres. The materials were characterised by nitrogen adsorption, FTIR spectroscopy, pyridine adsorption, thermogravimetry, SEM and XRD. The catalytic properties of the materials versus acid site concentration, alcohol type, zirconium content and reaction time were investigated in a batch reactor. The zirconium propoxide-modified materials appeared to be the most active and selective catalysts in the reaction studied. They showed complete furfural conversion with ca. 99% selectivity of furfuryl alcohol, which was attributed to the predominantly Lewis acidic character of these catalysts. High productivity, 15.2 mol_FA/mol_Zr·h, was obtained for the most active catalyst. Good catalytic stability was confirmed in repeated cycles. The oxide form of zirconium and aluminium species resulted in the mixed Lewis and Brönsted acidity, which encouraged further transformation of furfuryl alcohol into butyl furfuryl ether, angelica lactone and butyl levulinate. The elaborated catalyst offers a promising approach for converting renewable resources into industrially relevant chemicals. Full article

This study aimed at defining the infrared spectral signatures of volatile organic compounds (VOCs) of relevant interest for coffee bean authentication and quality control. Fourier Transform Infrared Spectroscopy was employed to acquire the mid-infrared absorption spectra of some representative coffee markers, namely Pyridine, 2-Methylpyrazine, 2,5-Dimethylpyrazine, Furfural, 5-Methylfurfural and Furfuryl Alcohol, with high resolution of 0.1 cm⁻¹. Mixtures of these VOCs simulating their amount in coffee seeds were analyzed using multilinear regression. The achieved results demonstrate the potentiality of coffee fingerprinting by VOC’s signature in the absorption spectra for discriminating coffee origin. Full article

To address the low selectivity in the electrocatalytic conversion of furfural (FFR) to furfuryl alcohol (FFA) under alkaline conditions, a Zn-based metal–organic framework (MBON-2) featuring a 3D hierarchical flower-like architecture self-assembled from nanosheets was synthesized via a simple hydrothermal method. Under optimal conditions, MBON-2 exhibited an extremely high selectivity of FFA (100%) and a high Faradaic efficiency (FE) of 93.19% at −0.2 V vs. RHE. Electrochemical impedance spectroscopy (EIS) revealed the excellent electron transfer and mass transport properties of MBON-2. In addition, in situ Fourier transform infrared (FTIR) spectroscopy studies confirmed the adsorption of FFR molecules onto the Zn and B sites of MBON-2 during the ECH of FFR, providing key insights into the hydrogenation mechanism. The numerous exposed B and Zn sites of the MBON-2, as well as its robust structural stability contributed to its outstanding catalytic performance in the electrochemical hydrogenation (ECH) of FFR. This work provides valuable guidelines for developing efficient Zn-based catalysts for the ECH of FFR. Full article

The repair efficiency of various self-healing materials often depends on the ability of the prepolymer and curing agent to form mixtures. This paper presents a synthesis and study of the properties of modified self-healing polyurethanes using the Diels–Alder reaction (DA reaction), obtained from a maleimide-terminated preform and a series of furan–urethane curing agents. The most commonly used isocyanates (4,4′-methylene diphenyl diisocyanate (MDI), 2,4-tolylene diisocyanate (TDI), and hexamethylene diisocyanate (HDI)) and furan derivatives (furfurylamine, difurfurylamine, and furfuryl alcohol) were used as initial reagents for the synthesis of curing agents. For comparative analysis, polyurethanes were also obtained using the well-known “traditional” approach—from furan-terminated prepolymers based on mono- and difurfurylamine, as well as furfuryl alcohol and the often-used bismaleimide curing agent 1,10-(methylenedi-1,4-phenylene)bismaleimide (BMI). The structure and composition of all polymers were studied using spectroscopic methods. Molecular mass was determined using gel permeation chromatography (GPC). Thermal properties were studied using TGA, DSC, and TMA methods. The mechanical and self-healing properties of the materials were investigated via a uniaxial tensile test. Visual assessment of the completeness of damage restoration after the self-healing cycle was carried out using a scanning electron microscope. It was shown that the proposed modified approach helps obtain more durable polyurethanes with a high degree of self-healing of mechanical properties after damage. Full article

Using low-cost transition-metal chlorides and furfuryl alcohol as raw materials, the (TiZrHfNbTa)C precursor was prepared, and a three-dimensional braided carbon fiber preform (C/C) coated with pyrolytic carbon (PyC) was used as the reinforcing material. A C/C-(TiZrHfNbTa)C composite was successfully fabricated through the precursor impregnation pyrolysis (PIP) process. Under extreme oxyacetylene ablation conditions (2311 °C/60 s), this composite material demonstrated outstanding ablation resistance, with a mass ablation rate as low as 0.67 mg/s and a linear ablation rate of only 20 μm/s. This excellent performance can be attributed to the dense (HfZr)₆(TaNb)₂O₁₇ oxide layer formed during ablation. This oxide layer not only has an excellent anti-erosion capability but also effectively acts as an oxygen diffusion barrier, thereby significantly suppressing further ablation and oxidation within the matrix. This study provides an innovative strategy for the development of low-cost ultra-high-temperature ceramic precursors and opens up a feasible path for the efficient preparation of C/C-(TiZrHfNbTa)C composites. Full article

As one of the most important platform chemicals, furfural (FAL) can be converted into high-value-added products such as furfuryl alcohol (FOL) through multiple pathways. Zirconium-based MOF-801 demonstrates exceptional catalytic potential for FAL conversion via catalytic transfer hydrogenation (CTH), owing to its unique crystal defects generated during growth. In this study, a series of defective MOF-801 samples were efficiently synthesized using an air–liquid segmented microfluidic technique. The characterization results reveal that the air–liquid segmented flow method not only regulates the defect content of MOF-801 to expose more active sites but also adjusts the crystal size and pore structures by precisely controlling the reaction time. The enhanced defects in MOF-801 significantly improved its catalytic performance. A-MOF-801-64 exhibited the highest activity, achieving over 99% FAL conversion and 98% FOL selectivity under mild conditions (130 °C, 12 h) using isopropanol as the hydrogen donor; this performance surpassed that of other reported Zr-based catalysts. This study will facilitate the practical applications of defect-engineered MOF-801 in upgrading biomass-derived chemicals. Full article

The objective of this study was to obtain and evaluate a coffee aroma extract/oil with sensorial attributes close to the original brew of Greek coffee for use in an instant Greek coffee powder. The oil was obtained directly from commercial Greek coffee by solid-liquid extraction using hexane as a solvent and treated with a series of hexane-ethanol mixtures (0:10, 1:4, 1:9) to remove the intense roasted flavor of the crude coffee oil obtained by hexane; the de-oiled coffee was used for the recovery of water-soluble compounds, and the produced water extract was freeze-dried. The aromatic volatiles of the coffee oil samples were analyzed by using a purge-and-trap device coupled to GC-MS, as well as sensory analysis. The instant Greek coffee powder was produced by mixing the freeze-dried base (74.4%) with the extract derived after treatment of the crude oil with hexane-ethanol mixture 1:4 (18.2%) and foaming agent (7.4%). Two different materials were studied as bases: instant coffee (F3_Gr-D) and ground Greek coffee (reference sample, C_Gr). The shelf-life stability of the produced powders was examined at three storage temperatures (25, 45, 60 °C). Instrumental analysis (purge-and-trap GC-MS) of aroma and sensory analysis (aroma, taste, staling, total sensory quality on a 1–9 hedonic scale) was conducted. Aroma loss (furfuryl alcohol, furfural, dimethyl pyrazines, ethyl methyl pyrazines) and scores for sensory attributes during storage were modeled using 1st and 0-order reaction kinetics, respectively. The storage temperature effect was expressed by the Arrhenius model (activation energy E_a). According to the results, the developed instant coffee powder presented satisfactorily the aroma characteristics of regular Greek coffee. The shelf life for the instant Greek coffee powder was estimated as 80 days (air packed) (based on 20% retention of furfuryl alcohol that was the most abundant aromatic volatile of Greek coffee aroma, ground as well as extract oil). Full article

The stabilization and upgrading of biomass and waste-derived pyrolysis oils requires development of reliable, active and low-cost upgrading catalysts. Basic natural materials can act as such catalysts and convert reactive oxygenates present in biomass pyrolysis oils. The conversion of furfural as a model compound has been conducted in an autoclave reactor at 200 °C to 300 °C using different calcium-based materials. CaCO₃, Ca(OH)₂, CaO, cement raw meal (CRM) and calcined cement raw meal (cCRM) were screened for their catalytic activity and characterized using X-ray powder diffraction (XRD) and X-ray fluorescence (XRF), nitrogen physisorption, carbon dioxide temperature programmed desorption (CO₂-TPD) and thermogravimetric analysis (TGA). CaCO₃ and CRM had low basicity and showed no catalytic activity at 200 to 300 °C. Notably, 90% conversion of furfural was achieved at 200 °C using Ca(OH)₂ with products being mostly furfural di- and trimers. For the basic CaO and cCRM, a temperature of 250 °C or above caused rapid polymerization of furfural. The proposed mechanism follows the Cannizzaro reaction of furfural, catalyzed by basic sites, polymerization of furfuryl alcohol, decarboxylation of furoic acid and decarbonylation of furfural, releasing CO, CO₂ and H₂O. Calcined cement raw meal showed the most promise for application as low-cost, sacrificial, basic catalyst. Full article