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This study employs a combined computational and experimental approach to elucidate the mechanisms governing the interaction between lignin and urea, impacting lignin dissolution and subsequent aggregation behavior. Molecular dynamics (MD) simulations reveal how the urea concentration and temperature influence lignin conformation and interactions. Higher urea concentrations and temperatures promote lignin dispersion by disrupting intramolecular interactions and enhancing solvation. Density functional theory (DFT) calculations quantitatively assess the interaction energy between lignin and urea, supporting the findings from MD simulations. Anti-solvent precipitation demonstrates that increasing the urea concentration hinders the self-assembly of lignin nanoclusters. The findings provide valuable insights for optimizing lignin biorefinery processes by tailoring the urea concentration and temperature for efficient extraction and dispersion. Understanding the influence of urea on lignin behavior opens up avenues for designing novel lignin-based materials with tailored properties. This study highlights the potential for the synergetic application of MD simulations and DFT calculations to unravel complex material interactions at the atomic level. [ABSTRACT FROM AUTHOR]

The development of inexpensive and robust bifunctional electrocatalysts for hydrogen evolution reactions (HER) and oxygen evolution reactions (OER) was crucial for renewable energy systems. Herein, a novel strategy for preparing CoNiRu alloy nano‐electrocatalyst capsulated by nitrogen‐doped biochar (CoNiRu@NLC) using carboxymethylated lignin macromolecules was proposed. CoNiRu@NLC exhibited excellent HER and OER performance, and the overall water splitting voltage was only 1.47 V at 10 mA/cm2 with excellent catalytic stability, which was superior to the noble metal catalysts Pt/C ‖ RuO2. Theoretical calculations confirmed the strong electron interaction between CoNiRu alloy and carbon layer, and XPS patterns proved that the electrons transfer from Ru to CoNi, significantly boosted the electrocatalytic activity. This study demonstrated the importance of lignin‐driven alloying on enhancing catalytic performance and provided a concept for the development of high‐efficiency catalysts and high‐value utilization of polyphenol biomass. [ABSTRACT FROM AUTHOR]

Lignin, rich in β‐O‐4 bonds and aromatic structure, is a renewable and potential resource for value‐added chemicals and promoting H2 evolution. However, direct photo‐reforming lignin remains a huge challenge due to its recalcitrant structure. Herein, a collaborative strategy is proposed by dispersing Pt on zinc‐vacancy‐riched ZnIn2S4 (Pt/VZn‐ZIS) for revealing the effect of lignin structure during photo‐reforming process with lignin models. And a series of theoretical calculations and experimental results show that lignin model substances with more nucleophilic group structures will have a stronger tendency to occur the photo‐reforming reactions. In addition, benefiting of Pt‐S electronic channel is formed by occupying Pt atom onto zinc vacancies in ZnIn2S4, which can effectively reduce the energy barrier of H2 evolution and accompany the selective oxidation of lignin model from Cα‐OH to Cα = O under simulated sunlight. The natural lignin is used to further demonstrate this selective oxidation mechanism. The presented work demonstrates the photo‐reforming lignin model mechanism and the influence of lignin‐structure during the process of photo‐reforming. [ABSTRACT FROM AUTHOR]

Rational design of efficient, stable, and inexpensive bifunctional electrocatalysts for oxygen evolution reactions (OER) and hydrogen evolution reactions (HER) is a key challenge to realize green hydrogen production via electrolytic water splitting. Herein, Ru nanoparticles and FeNi alloy heterojunction catalyst (Ru−FeNi@NLC) encapsulated via lignin‐derived carbon was prepared by self‐assembly precipitation and in situ pyrolysis. The designed catalyst displays excellent performance at 10 mA cm−2 with low overpotentials of 36 mV for HER and 198 mV for OER, and only needs 1.48 V for overall water splitting. Results and DFT calculations show the unique N‐doped lignin‐derived carbon layer and Ru−FeNi heterojunction contribute to optimized electronic structure for enhancing electron transfer, balanced free energy of reactants and intermediates in the sorption/desorption process, and significantly reduced reaction energy barrier for the HER and OER rate‐determining steps, thus improved reaction kinetics. This work provides a new in situ pyrolysis doping strategy based on renewable biomass for the construction of highly active, stable and cost‐effective catalysts. [ABSTRACT FROM AUTHOR]

Lignin is the most abundant by-product from the pulp and paper industry as well as the second most abundant natural renewable biopolymer after cellulose on earth. In recent years, transforming unordered and complicated lignin into ordered and uniform nanoparticles has attracted wide attention due to their excellent properties such as controlled structures and sizes, better miscibility with polymers, and improved antioxidant activity. In this review, we first introduce five important technical lignin from different sources and then provide a comprehensive overview of the recent progress of preparation techniques which are involved in the fabrication of various lignin-based nanoparticles and their industrial applications in different fields such as drug delivery carriers, UV absorbents, hybrid nanocomposites, antioxidant agents, antibacterial agents, adsorbents for heavy metal ions and dyes, and anticorrosion nanofillers. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Tween 20 improves the enzymatic hydrolysis of pretreated substrates. • Best improvement found for acid-pretreated substrates. • Improving action depends on pretreatments and hydrolysis conditions. • Tween 20 shows better improving action under harsh hydrolysis condition. • Tween 20 modifies lignin surface properties. Abstract The aim of this work was to study the effects of pretreatment process, hydrolysis condition and structural features of lignin on the improving action of surfactants (Tween 20) for enzymatic hydrolysis of pretreated wheat straw, and further to interpret the relation of these factors with the non-productive adsorption of cellulases on lignin. Tween 20 seemed to be more greatly improve cellulose conversion under harsher conditions. The surfactant showed more significant improvement for acid-pretreated substrates than oxidative-pretreated substrates. Highly-condensed lignin and phenolic hydroxyl groups showed much stronger adsorption ability to cellulases, while Tween 20 could well block the lignin–cellulase interactions recovering cellulose hydrolyzability. It was proposed that pretreatments altered lignin structures, resulting in the change of surface properties thus further impacting the lignin–cellulase interactions. Addition of Tween 20 could modify lignin surface properties to change its hydrophobicity, hydrogen bonding ability and surface charges, thus reducing the non-productive adsorption of proteins. [ABSTRACT FROM AUTHOR]

This work demonstrates an organic solvent fractionation method for lignin homogenization, which can effectively reduce the lignin heterogeneity and use each lignin fraction to prepare polyurethane foams (PUFs) with excellent mechanical properties. Such fractions were fully characterized by GPC, NMR (31P, 2D-HSQC), FTIR, and TG to obtain a detailed description of the structures and properties. The properties of PUFs from each lignin fraction showed higher compatibility than that from unfractionated industrial lignin, as studied by morphology and DSC analysis. The improvement of compatibility between the fractionated lignin fractions and polyethylene glycol can effectively enhance the mechanical properties of the prepared PUFs. The hysteresis loss (43.10%–51.85%) and resilience (95.81%–98.81%) of the fractionated lignin polyurethane foams (LPUFs) were better than that from the unfractionated LPUFs (hysteresis loss 41.64%, resilience 94.67%) at the lignin content of 5%. Subsequently, the strong relationships between lignin structures and PUF properties were demonstrated in detail. The suggested approach provides greater possibilities to prepare LPUFs with tunable properties based on real industrial lignin fractions, rather than modified lignin. • Solvent fractionation method was proposed for lignin homogenization. • Excellent compatibility between lignin fractions and polyurethane foams was formed. • The structure of lignin fractions determined the properties of polyurethane foams. • Tunable polyurethane foams based on real industrial lignin fractions were developed. [ABSTRACT FROM AUTHOR]

Synopsis: Lignin porous carbon/PANI composites were prepared via in- situ polymerization using lignin as carbon precursor. The PANI nanofibers interpenetrate the lamellar structure of lignin porous carbon, which endows high accessibility to ions and fast transfer for electrons, leading to the superior capacitance for the composite and the high energy density when assembled into supercapacitor. [Display omitted] Lignin porous carbons show good potential as carbon electrode materials for supercapacitors, but face the problem of low capacitance. Combining lignin porous carbons with polyaniline can achieve high capacitance. However, capacitance degradation resulting from the poor compatibility between lignin porous carbons and polyaniline has been the major obstacle for their application. In this work, three lignin porous carbons with different geometries were used as the hosts to anchor polyaniline for carbon/polyaniline composites via in- situ oxidative polymerization, and the compatibility between lignin porous carbons and polyaniline was investigated. It was determined the lamellar hierarchical lignin porous carbon with crumpled nanosheets can provide a large accessible surface area for the heterogeneous nucleation of aniline, which ensures uniform loading of interpenetrating polyaniline nanofibers. Benefiting from the interpenetrating conductive network and enhanced compatibility, the lamellar hierarchical porous carbon/polyaniline composite possesses a high capacitance of up to 643 F/g at 1.0 A/g and a sufficient capacitance of 390 F/g at 30.0 A/g. This work therefore provides design guidance for carbon hosts in high-performance supercapacitor composite electrodes. [ABSTRACT FROM AUTHOR]

• Utilizing aminated lignin as a precursor for N-doping modification of Ni. • The charges redistribution between Ni and NC carriers endows superior performance. • DFT unveils the energy barrier of ethanol coupling reaction on the Ni-N-C site. • N-doped engineering Ni for synthesis of higher alcohols from bioethanol. The selective conversion of biomass-derived ethanol into higher alcohols is a desirable but challenging process for the efficient production of value-added chemicals from alternative carbon sources. However, the current catalysts used in ethanol coupling exhibit low conversion rates and yields towards the formation of higher alcohols, necessitating significant improvements in their efficiency for practical applications. In this work, a lignin-derived N-doped carbon- supported Ni catalyst for ethanol coupling was designed and synthesized. The Ni@NC catalyst, synthesized using diethylenetriamine as the nitrogen source with a mass ratio of nitrogen source to lignin of 2:1 and a molar ratio of metal to lignin of 20:1, demonstrated excellent performance, with an ethanol conversion rate of 81.1% and a yield of C 4+ alcohols reaching 35.3%. Experimental results and density functional theory (DFT) calculations suggest that nitrogen-doped lignin, in appropriate quantities, along with the metal active component, forms a Ni-N-C structure that controls charge redistribution between the support and the Ni catalyst. This structure hinders the interaction of reaction intermediates and inhibits the production of by-products in the decomposition reaction, resulting in a higher yield of C 4+ alcohols. This study presents a more cost-effective and efficient approach for developing ethanol-coupling catalysts and holds promise for expanding the utility of lignin-derived catalysts. [ABSTRACT FROM AUTHOR]

Synergistic action of Ni-O-Fe structure promotes β-O-4 bond breaking for selective and efficient depolymerization of lignin. [Display omitted] • NiFe 2 O 4 nanosphere catalyst with irregular slit porous structure was prepared. • Efficient conversion of alkali lignans to alkylphenols and alkylguaiacols under milder conditions. • The synergism of Ni-O-Fe is the key to the efficient depolymerization of lignin. • The Lewis acidic center of the catalyst was significantly improved by the introduction of Ni, which promoted the β-O-4 bond breaking in lignin. Lignin shows great potential for sustainable production of high-quality fuels and value-added chemicals. The development of efficient and highly stable multifunctional catalysts for the depolymerization of lignin into aromatic chemicals remains a great challenge. In this work, environmentally friendly NiFe 2 O 4 spinel catalyst characterizing with rich oxygen vacancies and porous structures was constructed by introducing Ni to modulate the coordination environment of cations in Fe 3 O 4. Under optimal conditions, the conversion of alkali lignin catalyzed by NiFe 2 O 4 reached 91.0%, the yield of liquid product reached 83.6% and the yield of aromatic monomer products was 31.7%. Combined results from catalyst characterization, product analysis and density functional theory calculations showed that the Lewis acidic center of the catalyst was significantly improved by the introduction of Ni, which promoted the C-O bond breaking in lignin. The Ni-O-Fe structure facilitated the adsorption of lignin substrates and reaction intermediates, which resulted in the improved depolymerization efficiency of lignin. The present work provides valuable insights into the depolymerization of lignin by spinel catalysts, and offers ideas for the future design and development of binary or even ternary spinel catalysts for the depolymerization of lignin. [ABSTRACT FROM AUTHOR]

• The ternary DES was used to deconstruct softwood. • DES (AlCl 3 -1,4-BDO-ChCl) has the best pretreatment effect. • The lignin has the lightest color with L* value of 77.9. • The lignin-blended sunscreen has an SPF of 26.95 ± 4.20. Lignin is the most abundant natural phenolic polymer. However, the severe condensations of industrial lignin resulted in an undesirable apparent morphology and darker color, which hindered its application in the field of daily chemicals. Therefore, a ternary deep eutectic solvent is used to obtain lignin with light-color and low condensations from softwood. The results showed that the brightness value of lignin extracted from aluminum chloride-1,4-butanediol-choline chloride at 100 °C and 1.0 h was 77.9, and the lignin yield was 32.2 ± 0.6%. It is important that 95.8% of β-O-4 linkages (β-O-4 and β-O-4′) was retained. Lignin is used to prepare sunscreens and is added to physical sunscreens at 5%, with SPF up to 26.95 ± 4.20. Meanwhile, enzyme hydrolysis experiments and reaction liquid composition tests were also conducted. In conclusion, a systematic understanding of this efficient process could facilitate high-value utilization of lignocellulosic biomass in industrial processes. [ABSTRACT FROM AUTHOR]

• NaOH-catalyzed organosolv pretreatment was developed to remove lignin and retain carbohydrates. • The combination of NaOH and ethanol had synergistic effect on improving enzymatic hydrolysis. • Adding Tween 80 promoted enzymatic hydrolysis and shortened hydrolysis time. • The highest glucose yield of 95.1% was obtained after hydrolysis for 24 h. In this study, NaOH-catalyzed organosolv pretreatment with different loading of NaOH (0–10%) was proposed to disrupt the recalcitrant structure by degrading lignin, reserve the majority of cellulose and hemicellulose, and improve the enzymatic efficiency of sugarcane bagasse. It was found that the higher loading of NaOH during organosolv pretreatment yielded more glucose, and the synergistic performance of NaOH and ethanol on enzymolysis was superior to that pretreated with only NaOH and only ethanol during two-step pretreatment. Furthermore, Tween 80 was added to determine its influence on enzymolysis after NaOH-catalyzed organosolv pretreatment, leading to the highest glucose yield of 95.1% at 24 h, which saved 2/3 hydrolysis time while generating the similar glucose yield comparing with that without Tween 80. However, the increased yields of glucose by adding Tween 80 were decreased as hydrolysis time was prolonged from 6 h to 24 h. [ABSTRACT FROM AUTHOR]