[article-cris] Kemian tekniikan korkeakoulu / CHEM

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  • Stiff and self-healing hydrogels by polymer entanglements in co-planar nanoconfinement
    (2025-03-07) Liang, Chen; Dudko, Volodymyr; Khoruzhenko, Olena; Hong, Xiaodan; Lv, Zhong-Peng; Tunn, Isabell; Umer, Muhammad; Timonen, Jaakko; Linder, Markus; Breu, Josef; Ikkala, Olli; Zhang, Hang
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Many biological tissues are mechanically strong and stiff but can still heal from damage. By contrast, synthetic hydrogels have not shown comparable combinations of properties, as current stiffening approaches inevitably suppress the required chain/bond dynamics for self-healing. Here we show a stiff and self-healing hydrogel with a modulus of 50 MPa and tensile strength up to 4.2 MPa by polymer entanglements in co-planar nanoconfinement. This is realized by polymerizing a highly concentrated monomer solution within a scaffold of fully delaminated synthetic hectorite nanosheets, shear oriented into a macroscopic monodomain. The resultant physical gels show self-healing efficiency up to 100% despite the high modulus, and high adhesion shear strength on a broad range of substrates. This nanoconfinement approach allows the incorporation of novel functionalities by embedding colloidal materials such as MXenes and can be generalized to other polymers and solvents to fabricate stiff and self-healing gels for soft robotics, additive manufacturing and biomedical applications.
  • From low conductivity to high energy efficiency : The role of conductive polymers in phase change materials
    (2025-03-15) Yazdani McCord, Maryam R.; Seppälä, Ari; Pourakbari-Kasmaei, Mahdi; Zimmerman, Julie B.; Rojas, Orlando J.
     A2 Katsausartikkeli tieteellisessä aikakauslehdessä
    Phase change materials (PCMs) face a significant obstacle in practical applications and energy efficiency due to their inherently low thermal conductivity. One promising solution to this limitation involves integrating conductive polymers (CPs) into PCMs. This approach not only enhances thermal conductivity—critical for efficient energy storage and release—but also introduces electrical conductivity, enabling dual functionalities such as electrothermal conversion and rapid charging and discharging. Although CPs have been extensively utilized for this purpose, there is a noticeable gap in existing reviews that specifically focus on CP-enhanced PCMs. To address this gap, this comprehensive review examines experimental research aimed at improving the electrothermal characteristics of PCMs, with an emphasis on boosting conductivity and storage efficiency through CP incorporation. The review begins by providing an overview of the fundamental principles of electrical and thermal conduction in materials. It then explores commonly used CPs—such as polypyrrole, polyaniline, and poly(3,4-ethylenedioxythiophene) (PEDOT)—and their integration strategies with PCMs. The discussion highlights the unique properties of these polymers and their contributions to enhancing the thermal and electrical conductivity of PCMs. Additionally, it investigates the formation of conductive pathways and their role in amplifying the energy efficiency of nano-enhanced PCMs, comparing the effects of various nano-additives. The study further explores potential applications of CP-enhanced PCMs across diverse fields, including electronics, wearables, energy systems, and advanced thermally regulative materials. To provide a well-rounded perspective, the review outlines recent advancements, identifies current challenges and limitations, and highlights future research opportunities. By fostering a deeper understanding of the interplay between PCMs and CPs, this review contributes to the ongoing efforts to optimize thermal properties and multifunctionality, paving the way for innovative applications and improved energy solutions.
  • Atom-wise formulation of the many-body dispersion problem for linear-scaling van der Waals corrections
    (2025-02-03) Muhli, Heikki; Ala-Nissila, Tapio; Caro, Miguel A.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    A common approach to modeling dispersion interactions and overcoming the inaccurate description of long-range correlation effects in electronic structure calculations is the use of pairwise-additive potentials, as in the Tkatchenko-Scheffler [Phys. Rev. Lett. 102, 073005 (2009)10.1103/PhysRevLett.102.073005] method. In previous work [H. Muhli, Phys. Rev. B 104, 054106 (2021)10.1103/PhysRevB.104.054106], we have shown how these are amenable to highly efficient atomistic simulation by machine learning their local parametrization. However, the atomic polarizability and the electron correlation energy have a complex and nonlocal many-body character and some of the dispersion effects in complex systems are not sufficiently described by these types of pairwise-additive potentials. Currently, one of the most widely used rigorous descriptions of the many-body effects is based on the many-body dispersion (MBD) model [A. Tkatchenko, Phys. Rev. Lett. 108, 236402 (2012)10.1103/PhysRevLett.108.236402]. In this work, we show that the MBD model can also be locally parametrized to derive a local approximation for the highly nonlocal many-body effects. With this local parametrization, we develop an atomwise formulation of MBD that we refer to as linear MBD (lMBD), as this decomposition enables linear scaling with system size. This model provides a transparent and controllable approximation to the full MBD model with tunable convergence parameters for a fraction of the computational cost observed in electronic structure calculations with popular density-functional theory codes. We show that our model scales linearly with the number of atoms in the system and is easily parallelizable. Furthermore, we show how using the same machinery already established in previous work for predicting Hirshfeld volumes with machine learning enables access to large-scale simulations with MBD-level corrections.
  • Strongly reduced thermal conductivity in hybrid ZnO/nanocellulose thin films
    (2017-05) Jin, Hua; Marin, Giovanni; Giri, Ashutosh; Tynell, Tommi; Gestranius, Marie; Wilson, Benjamin P.; Kontturi, Eero; Tammelin, Tekla; Hopkins, Patrick E.; Karppinen, Maarit
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Utilizing a combination of atomic layer deposition and dip-coating techniques, we have incorporated natural nanocellulose fibers into an inorganic matrix in order to create a layered hybrid inorganic–organic thin-film structure. Such layer-engineered hybrid materials with an unorthodox combination of components are highly potential candidates for exciting new properties. Here, we show a more than an order of magnitude reduction in the cross-plane thermal conductivity for ZnO thin films achieved with the regular inclusion of the cellulose nanofiber layers. We foresee that a similar approach as presented here for ZnO could also be applied to other inorganic materials based on earth-abundant elements to influence their thermal transport properties.
  • Role of Salt and Water in the Plasticization of PDAC/PSS Polyelectrolyte Assemblies
    (2016) Zhang, Ran; Zhang, Yanpu; Antila, Hanne; Lutkenhaus, Jodie L.; Sammalkorpi, Maria
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    In this work, we investigate the effect of salt and water on plasticization and thermal properties of hydrated poly(diallyldimethylammonium chloride) (PDAC) and poly(sodium 4-styrenesulfonate) (PSS) assemblies via molecular dynamics simulations and modulated differential scanning calorimetry (MDSC). Commonly, both water and salt are considered to be plasticizers of hydrated polyelectrolyte assemblies. However, the simulation results presented here show that while water has a plasticizing effect, salt can also have an opposite effect on the PE assemblies. On one hand, the presence of salt ions provides additional free volume for chain motion and weakens PDAC–PSS ion pairing due to electrostatic screening, which contributes toward plasticization of the complex. On the other hand, salt ions bind water in their hydration shells, which decreases water mobility and reduces the plasticization by hydration. Our MDSC results connect the findings to macroscopic PE plasticization and the glass-transition-like thermal transition Ttr under controlled PE hydration and salt content. This work identifies and characterizes the dual nature of salt both as plasticizer and hardener of PE assemblies and maps the interconnection of the influence of salt with the degree of hydration in the system. Our findings provide insight into the existing literature data, bear fundamental significance in understanding of hydrated polyelectrolyte assemblies, and suggest a direct means to tailor the mechanical characteristics of PE assemblies via interplay of water and salt.
  • Multi-layer nanopaper based composites
    (2017-04) Mautner, Andreas; Lucenius, Jessica; Österberg, Monika; Bismarck, Alexander
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Native cellulose nanofibrils (CNF) were prepared from bleached birch pulp without any chemical or enzymatic pretreatment. These CNF were modified by adsorption of a small amount of water-soluble polysaccharides and used to prepare nanopapers, which were processed into composites by lamination with an epoxy resin and subsequently cured. The results were compared to the properties of composites prepared using bacterial cellulose nanopapers, since bacterial cellulose constitutes highly pure and crystalline cellulose. It was found that both types of nanopapers significantly improved both the thermal stability and mechanical properties of the epoxy resin. As anticipated, addition of only 2 wt% of water-soluble polysaccharides efficiently hindered crack-propagation within the nanopaper and significantly improved the tensile strength and work of fracture compared to composites containing a conventional nanopaper reinforcement. The mechanical properties of the composites thus reflected the improvement of the nanopaper properties by the polysaccharides. Moreover, it was possible to predict the properties of the final composite from the mechanical performance of the nanopapers.
  • Co-simulations of induction machines coupled with a radial ball bearing for mechanical defects analysis
    (2025) El Bouharrouti, Nada; Sitnikov, Maksim; Hemeida, Ahmed; Martin, Floran; Kudelina, Karolina; Naseer, Muhammad U.; Belahcen, Anouar
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    In this paper, two co-simulations are introduced to study the behaviour of a 2-D finite-element model and a magnetic equivalent model of an induction machine, both coupled with a mechanical radial ball bearing model. This comprehensive approach allows for the generation of synthetic vibration and current signals of a ball bearing mounted on a shaft, taking into account the entire machinery. The study investigates the misalignment effect caused by an inner ring defect in a ball bearing, analysing its impact on the current of the IM models. Likewise, the effects of eccentricity in the induction machine models on rotor vibration are studied through their coupling with the mechanical ball bearing model. This multiphysics co-simulation provides a novel numerical application to generate data relative to mechanical defects in induction machines. By using this coupled method, an inner ring defect of 1 mm depth and 3 mm length in the bearing model is accurately identified in the frequency spectrum of the stator current, whereas eccentricity faults for levels ranging between 5% and 40% are detected in the vibration spectrum of the ball bearing. The findings are accurately supported by related theory, and further validated through experimental verification for the case of the inner ring fault.
  • A novel Cr2O3/Cr-doped g-C3N4 photocatalyst with a narrowed band gap for efficient photodegradation of tetracycline
    (2024-04-01) Wang, Sen; Chen, Hong; Lin, Qing; Lu, Qian; Lv, Wei; Wang, Can; Yu, Linhao; Li, Yingying; Li, Yongdan
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Two significant strategies for enhancing photocatalyst performance are heterojunction construction and band gap modulation, but up until now, these methods have typically been treated separately. This work examines a strategy combining the heterojunction with a mid-gap state to prepare a novel Cr2O3 modified Cr-doped g-C3N4 photocatalyst for antibiotics degradation. According to the characterization results, the integration of Cr 3d orbital energy level into the original band gap of g-C3N4 results in the formation of Cr-doped g-C3N4, leading to a reduction in the band gap from 2.80 eV to 2.36 eV. Besides, the constructed Z-type heterojunction enhances the separation of photoinduced carriers. The degradation experiments of tetracycline proved the significant enhancement in the photocatalytic performance of the prepared catalyst. In addition, the degradation effect of the prepared catalyst on tetracycline in micro-polluted lake water was also investigated, revealing the applicability of the catalyst in the purification of natural water environments.
  • La0.7Sr0.3Fe0.9Ni0.1O3−δ-Ce0.8Sm0.2O2−δ Composite Cathode with a Hollow Nanofiber Structure Prepared through Coaxial Electrospinning for Protonic Ceramic Fuel Cells
    (2024-11-11) Zhao, Xin; Liu, Wen; Zhang, Jian; Lu, Xuanlin; Chen, Jiaxuan; Shao, Tianqi; Zhang, Jinpeng; Zhao, Yicheng; Li, Yongdan
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Rational design of the electrode microstructure is an important strategy to improve the performance of solid oxide fuel cells. Electrospinning is an effective approach for the production of electrode materials with a nanofiber microstructure, which provides straight and continuous pathways for ionic and electronic conduction. In this study, the self-assembled La0.7Sr0.3Fe0.9Ni0.1O3−δ (LSFN)-Ce0.8Sm0.2O2−δ (SDC) composite with a hollow nanofiber structure is synthesized as the cathode material of protonic ceramic fuel cells (PCFCs) through a coaxial electrospinning process. LSFN and SDC are both distributed uniformly in the composite cathode. Compared with composite cathodes prepared through electrospinning with solid and core-shell nanofiber structures, the hollow-fiber LSFN-SDC cathode shows a higher specific surface area and provides more channels for gas diffusion, both of which are beneficial for the oxygen reduction reaction. The LSFN-SDC composite cathode with the hollow fiber structure exhibits the lowest polarization resistance of 0.035 Ω cm2 at 700 °C. A PCFC with that cathode shows a maximum power density of 1598 mW cm-2 and a promising short-term stability at 700 °C.
  • A highly active catalytic cathode La0.8Sr0.2Co0.7Ni0.3O3-δ for protonic ceramic fuel cells: Experimental and computational insights
    (2025-02-28) Yao, Penghui; Zhang, Jian; Qiu, Qianyuan; Zhao, Yicheng; Yu, Fangyong; Li, Yongdan
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Protonic ceramic fuel cell (PCFC) is an emerging technology for efficient energy conversion, with which the performance of a cathode with high oxygen reduction reaction (ORR) kinetics is crucial. In this work, we report a glycine-nitrate technique to synthesize a highly active catalytic cathode La0.8Sr0.2Co0.7Ni0.3O3-δ (LSCN). Electrochemical measurement and density functional theory (DFT) simulation are adopted to reveal ORR mechanism. Computational simulations reveal that the presence of oxygen vacancies significantly reduces ORR overpotential by stabilizing reaction intermediates and lowering the proton transfer energy barrier. The fuel cell with LSCN reached the excellent PCFC with a peak power density of 1.62 W cm−2 at 700 °C. Durability testing over 100 h showed no significant degradation, demonstrating the stability of the LSCN cathode. This work provides a path to the rational design of high-performance PCFC cathode.
  • The application of graphitic nitrogen from corn stover for the selective catalytic oxidation of 5-hydroxymethyl furfural
    (2025-02-15) Lv, Wei; Wang, Yao; Chen, Hong; Tang, Yongqi; Li, Yongdan
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Nitrogen atom-doped biomass carbon prepared from corn stover is a newly discovered metal-free catalyst that shows good activity on the selective oxidation of 5-hydroxymethylfurfural (5-HMF) to 2,5-diformylfuran (DFF). Here, the presence of graphitic nitrogen on the catalyst surface activated the oxygen adsorbed on the carbon sites next to the graphitic nitrogen in the carbon material and promoted the formation of oxygen radicals on the surface-active sites, improving the HMF oxidation process. The results show that the catalyst NC-800 reacted with acetonitrile as the reaction solvent at 110 °C and 1.0 MPa O2 for 8 h to obtain 93.0 % HMF conversion and 94.4 % DFF selectivity, and the 5-HMF conversion and DFF selectivity were maintained at more than 85 % after five cyclic tests, with excellent cyclic stability. One of the main factors influencing the material flaws is the variation in pyrolysis temperature. Using maize stover, a readily available and renewable biomass, in the catalytic oxidation of biomass platform compounds may improve biomass utilization more extensively.
  • Femtosecond-laser-surface-nanostructured glass for building-integrated photovoltaics
    (2025-04) Meng, Lingju; Awashra, Moe; Hamed, Sara; Gnatyuk, Dmytro; Vähänissi, Ville; Jokinen, Ville; Savin, Hele; Liu, Xiaolong
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The emerging luminescent solar concentrators (LSC) for building-integrated photovoltaics (BIPV) face challenges such as narrow conversion spectrum, material degradation, high costs, and safety concerns, while their reliance on complex fabrication processes further hinders their practical application in large-area systems. In this paper, we present a novel application of femtosecond-laser-nanostructured borosilicate glass for BIPV, offering a promising alternative to traditional LSC windows. Utilizing a scalable, one-step femtosecond laser direct writing process, we fabricate nanostructured borosilicate glass specifically designed to effectively scatter incident light toward solar cells positioned at the edges of the glass. To optimize the laser processing, we perform comprehensive characterizations using scanning electron microscopy, X-ray diffraction, Raman spectroscopy, photoluminescence spectroscopy, and spectrophotometry. The proof-of-concept system demonstrates that the glass processed at an optimized scan speed exhibits a 55-fold increase in photocurrent generation compared to unprocessed glass, highlighting its enhanced optical efficiency. Additionally, a hydrophobic coating is applied on the nanostructured glass to confer self-cleaning properties, achieving superhydrophobicity with advancing and receding contact angles of approximately 170°. This novel approach to utilizing nanostructured glass for solar concentration shows considerable promise for improving both the efficiency and practicality of building-integrated photovoltaics.
  • Introducing Oxygen Vacancies into a WO3 Photoanode through NaH2PO2 Treatment for Efficient Water Splitting
    (2024-11-12) Huang, Qiuyang; Zhao, Yicheng; Li, Yongdan
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    WO3, with a high light absorption capacity and a suitable band structure, is considered a promising photoanode material for photoelectrochemical water splitting. However, the poor photoinduced electron-hole separation efficiency limits its application. Herein, we report an effective strategy to suppress electron-hole recombination by introducing oxygen vacancies (OV) on the surface of a WO3 photoanode through NaH2PO2 treatment. An OV-enriched amorphous surface layer with a thickness of 4 nm is formed after NaH2PO2 treatment, which increases the charge carrier density and enlarges the electrochemical surface area of the photoanode. The charge separation and surface injection efficiencies are both improved after NaH2PO2 treatment, and the charge transfer process of the photoanode is accelerated consequently. The current density of the modified WO3 photoanode reaches 0.96 mA cm-2 at 1.23 V.
  • LSPR-assisted W18O49/ZnO S-scheme heterojunction for efficient photocatalytic CO2 N-formylation of aniline
    (2024-12) Chen, Jiafa; Bai, Peng; Yuan, Shibo; He, Yi; Niu, Zifan; Zhao, Yicheng; Li, Yongdan
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Designing highly efficient photocatalyst for the valorization of CO2 is an ideal strategy to reduce greenhouse gas emissions and utilize solar energy. In this study, a S-scheme heterojunction photocatalyst is fabricated by solvothermal impregnation of ZnO on W18O49 for photocatalytic CO2 N-formylation of aniline. The localized surface plasmon resonance effect of W18O49 improves the absorption capacity for long-wave light significantly, and the hot electrons generated in W18O49 with a high energy can migrate to the conduction band of ZnO and thus enhance the photocatalytic reduction ability. Meanwhile, the S-scheme heterojunction facilitates the separation of photoinduced charge carriers and preserves the redox ability of W18O49/ZnO composite photocatalyst. The conversion of aniline reaches 99.1% after 5 h reaction under visible light irradiation at room temperature with an N-formylaniline selectivity of 100%. A possible photocatalytic reaction mechanism is proposed. This study paves a promising way for the design of highly efficient photocatalyst and the sustainable utilization of CO2.
  • Bis(2-chloroethyl)sulfane revisited: (ClH4C2)2S···S(C2H4Cl) dimers by S···S interaction in the solid state
    (2024-12-17) Kraus, Florian; Graubner, Tim; Buchner, Magnus R.; Metzulat, Manfred; Karttunen, Antti J.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We synthesized bis(2-chloroethyl)sulfane, S(C2H4Cl)2, and showed its purity by various analytic methods. Its previously unknown crystal structure shows a peculiar intermolecular S···S interaction leading to (ClH4C2)2S···S(C2H4Cl)2 dimers. The S···S interaction could also be reproduced and investigated by quantum chemical calculations. As the C-C bonds have been observed unexpectedly short in the range from 1.505(2) to 1.509(2) Å, the chemical bonds within S(C2H4Cl)2 have also been investigated quantum chemically. Intrinsic bonding orbitals (IBOs) showed that while the C-Cl bond is slightly polarized, the C-C and C-S bonds appear purely covalent, as expected. The electron density between the respective two C atoms is decreased by the attached Cl atom so that the two C atoms move closer to each other. High-resolution low-temperature Raman spectra of solid S(C2H4Cl)2 are presented, and the bands are assigned with the aid of quantum chemical solid-state calculations.
  • A coarse-grained model for aqueous two-phase systems : Application to ferrofluids
    (2025-05-15) Scacchi, Alberto; Rigoni, Carlo; Haataja, Mikko; Timonen, Jaakko V.I.; Sammalkorpi, Maria
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Aqueous two-phase systems (ATPSs), phase-separating solutions of water soluble but mutually immiscible molecular species, offer fascinating prospects for selective partitioning, purification, and extraction. Here, we formulate a general Brownian dynamics based coarse-grained simulation model for an ATPS of two water soluble but mutually immiscible polymer species. Including additional solute species into the model is straightforward, which enables capturing the assembly and partitioning response of, e.g., nanoparticles (NPs), additional macromolecular species, or impurities in the ATPS. We demonstrate that the simulation model captures satisfactorily the phase separation, partitioning, and interfacial properties of an actual ATPS using a model ATPS in which a polymer mixture of dextran and polyethylene glycol (PEG) phase separates, and magnetic NPs selectively partition into one of the two polymeric phases. Phase separation and NP partitioning are characterized both via the computational model and experimentally, under different conditions. The simulation model captures the trends observed in the experimental system and quantitatively links the partitioning behavior to the component species interactions. Finally, the simulation model reveals that the ATPS interface fluctuations in systems with magnetic NPs as a partitioned species can be controlled by the magnetic field at length scales much smaller than those probed experimentally to date.
  • Influence of moisture on the sound absorption properties of wood-based pulp fibre foams
    (2024-09) Cucharero Moya, Jose; Awais, Muhammad; Valkonen, Mikko; Kammiovirta, Kari; Rautkari, Lauri; Lokki, Tapio; Hänninen, Tuomas
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The use of wood fibres, and other biofibres in general, as raw materials to produce sound absorbers has gradually increased lately. The main reason for their increased use is their contribution to reducing CO2 from the atmosphere by binding CO2 into the building structure for decades. Understanding of the ultrastructure of wood fibres is essential as it has a strong influence on the fibre properties, and thus, on the final material properties. In this work, the effect of moisture on the sound absorption properties of wood-based pulp fibre foams has been studied. It is shown that increasing moisture content (> 9%) in pulp fibres leads to greater sound absorption at low-mid frequencies. Fibre swelling, increasing fibre flexibility, and increasing foam bulk density with increasing fibre moisture content are hypothesized as the causes for the increase in sound absorption. Hygroexpansion, mechanical properties as well as moisture absorption capability of different types of pulp fibres are studied and related to their sound absorption properties. It is concluded that, in addition to fibre diameter and bulk density of foams, the elastic properties of the pulp fibres are partially responsible for the improved sound absorption of the foams exposed to greater relative humidity conditions.
  • Research progress on 5-hydroxymethylfurfural electrocatalytic or photocatalytic oxidation coupling with hydrogen production
    (2025-02-28) Wang, Yao; Chen, Hong; Tang, Yongqi; Li, Yongdan
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Biomass and hydrogen serve as crucial alternatives to fossil fuels, addressing climate change and the shortage of fossil fuels. Hydrogen offers high energy density and emits no carbon, while biomass is abundant and renewable. Nevertheless, green hydrogen production via electrocatalysis or photocatalysis faces challenges such as slow kinetics and low efficiency. Oxidation catalysis of biomass derivatives, particularly 5-hydroxymethylfurfural (HMF), has the potential to substitute for the oxygen evolution reaction (OER) in hydrolysis, leading to a significant increase in hydrogen evolution and the production of valuable products such as 2,5-diformylfuran (DFF), 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), and 2,5-furan dicarboxylic acid (FDCA). This review explores recent advancements in electrocatalytic, photocatalytic, and photoelectrocatalytic HMF oxidation coupled with hydrogen production. This study provides a theoretical basis and practical guidance for catalyzing HMF oxidation coupled with hydrogen production through a detailed analysis of the reaction mechanism of HMF oxidation coupled with hydrogen generation and the performance of bifunctional catalysts.
  • Syngas Conversion to Higher Alcohols via Wood-Framed Cu/Co-Carbon Catalyst
    (2025-01-27) Yan, Guihua; Pršlja, Paulina; Chen, Gaofeng; Kang, Jiahui; Liu, Yongde; Caro, Miguel A.; Chen, Xi; Zeng, Xianhai; Peng, Bo
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Syngas conversion into higher alcohols represents a promising avenue for transforming coal or biomass into liquid fuels. However, the commercialization of this process has been hindered by the high cost, low activity, and inadequate C2+OH selectivity of the catalysts. Herein, we have developed Cu/Co carbon wood catalysts, offering a cost-effective and stable alternative with superior selectivity for catalytic conversion. The formation of Cu/Co nanoparticles was found, influenced by water-1,2-propylene glycol ratios in the solution, resulting in bidisperse nanoparticles. The Cu/Co-CW-W1P1 catalyst (the ratio between water and 1,2-propanediol is 0.5:0.5) exhibited a remarkable CO conversion rate of 74.8% and a selectivity of 58.7% for C2+OH, primarily comprising linear primary alcohols. This catalyst demonstrated enduring stability and selectivity under industrial conditions, maintaining its efficacy for up to 350 h of operation. We also employed density functional theory (DFT) to analyze selectivity, particularly focusing on the binding strength of CO, a crucial intermediate for subsequent reactions leading to the formation of alcohols. DFT identified the pathway of CHx and CO coupling, ultimately yielding C2H5OH. This computational understanding, coupled with the high performance of the Cu/Co-carbon wood catalyst, paves the way to develop catalytically selective materials tailored for higher alcohol production from a nature-based source.
  • Lignin Nanofiber Flexible Carbon Aerogels for Self-Standing Supercapacitors
    (2025-02-01) Cho, Mi Jung; Yiu, Justine; Lin, Li Ting; Hua, Qi; Karaaslan, Muzaffer A.; Renneckar, Scott
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Renewable feedstocks are sought for clean technology applications, including energy storage applications. In this study, LignoForce™ lignin, a biobased aromatic polymer commercially isolated from wood, was fractioned into two parts using acetone, and the resulting lignin fractions had distinct thermo-rheological behavior. These two fractionated lignins were combined in various ratios and transformed into nanofibers by electrospinning. Subsequently, electrospun fiber materials were disrupted by agitating the mats in water, and the materials were transformed into ultralight 3D aerogels through lyophilization and post-process controlled heating. Using only this combination of two fractions, the morphology of lignin nanofibers was tailored by heat treatment, resulting in lignin aerogels with high flexibility and significant shape recovery properties. Various microscale structures of lignin fibers impacted the resulting physical properties of the elastic aerogel materials, such as resilience, compressive strength, and electrical conductivity for the corresponding carbonized samples. By exploiting lignin's sensitivity to heat and tailoring the thermal properties of the lignin through fractionation, the work provided an interesting path to form robust lignin-derived functional materials without any toxic chemical additives and significant ability to serve as free-standing electrodes with specific capacitance values better than some graphene-based supercapacitors.