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Replacing fossil resources as the primary source of carbon‐based chemicals by alternative feedstocks, while implementing more sustainable production routes, has become imperative for environmental and resource sustainability. In this context, lignin, often treated as a biomass waste, emerges as an appealing candidate, considering the principles of circular economy. For this pursuit, depolymerization methods offer potential strategies to harness lignin to produce valuable organic chemicals, while electrocatalysis processes stand out especially in the context of sustainability, as they can be powered by electricity from renewable sources. This minireview article explores the pivotal role of various electrocatalysts in lignin depolymerization, investigating both oxidative and reductive pathways. Emphasizing recent advancements, the review delves into the diverse nature of electrocatalysts and their influence on lignin valorization. Highlighting current trends, the discussion encompasses the catalytic mechanisms and selectivity of electrochemical processes employed for lignin breakdown. Additionally, some insights into emerging technologies are also offered, emphasizing the need for sustainable and efficient strategies. By providing an overview of the field, this minireview aims to guide future research endeavors toward innovative electrocatalytic approaches for lignin depolymerization, paving the way for sustainable biorefinery processes. [ABSTRACT FROM AUTHOR]

Replacing crude oil as the primary industrial source of carbon‐based chemicals has become crucial for both environmental and resource sustainability reasons. In this scenario, wood arises as an excellent candidate, whilst depolymerization approaches have emerged as promising strategies to unlock the lignin potential as a resource in the production of high‐value organic chemicals. However, many drawbacks, such as toxic solvents, expensive catalysts, high energy inputs, and poor product selectivity have represented major challenges to this task. Herein, we present an unprecedented approach using electrocatalysis for the simultaneous depolymerization and dearomatization of lignin in aqueous medium under ambient conditions. By employing water/sodium carbonate as a solvent system, we demonstrated a pathway for selectively depolymerizing lignin under reductive electrochemical conditions using carbon as an electrocatalyst. After reductive electrocatalysis, the presence of aromatic compounds was no longer detected via nuclear magnetic resonance (NMR) spectroscopy. Further characterization by NMR, FTIR spectroscopy, and mass spectrometry revealed the major presences of sodium levulinate, sodium 4‐hydroxyvalerate, sodium formate, and sodium acetate as products. By achieving a complete dearomatization, valuable aliphatic intermediates with enhanced reactivity were selectively obtained, opening new avenues for further synthesis of many different organic chemicals, and contributing to a more sustainable and circular economy. [ABSTRACT FROM AUTHOR]

The development of sustainable valorization methods for lignin is a challenging task because the vast majority of the reported studies involve either harsh conditions or expensive transition metal catalysts. Inspired by the sunlight degradation of lignin compounds, known as lignin yellowing, the use of a commercially available cheap organic photoinitiator, namely, phenacyl bromide (PAB) is reported here, for the efficient cleavage of lignin model compound 2‐phenoxyacetophenone (2‐PAP) and for the depolymerization of soda pulped lignin (SL) under UV‐A irradiation and ambient conditions. Real‐time NMR investigations of the photoreaction between 2‐PAP and PAB shed light on the possible reaction mechanisms involving different radical species, HBr, and molecular oxygen. Interestingly, combined spectral, chromatographic, powder X‐ray diffraction, and thermal studies of the photoreaction between PAB and SL indicate the formation of guaiacyl alcohol as the main product. The unprecedented performance of PAB is attributed to the excess generation of phenacyl radicals, the generation of photolabile brominated species, and HBr playing key roles in the cleavage of β‐O‐4 linkages. This work represents a new edge for sustainable lignin valorization under mild reaction conditions and offers the opportunity for large‐scale production of valuable aromatics using technical lignins as feedstock. [ABSTRACT FROM AUTHOR]

The high degree of interest in scientific topics (science and research) has been observed especially since the pandemic. This includes the ongoing transition of the chemical industry toward sustainability because the accompanied changes have to be coordinated in dialogue with society. Parallelly, there is increasing interest in science communication in general, as well as the increasing need for its proper understanding. How we communicate is probably today as important as what we communicate. The purpose of this study is to explore how society perceives science, research, scientific results, and their role in the modern world. The method used in the study was a diagnostic survey, and the data was collected using an online questionnaire. This study used a quantitative method. The results showed that science communication needs to be developed much more with special attention paid to the economic, social, and political context. The results analysed and integrated in this article could provide substantive suggestions and help develop science communication. [ABSTRACT FROM AUTHOR]

The immobilization and structural analysis of platinum nanoparticles on a nitrogen‐rich, bipyridine‐containing covalent triazine framework (bpyCTF) having structural defects are disclosed by taking advantage of 15N solid‐state nuclear magnetic resonance measurements at natural 15N isotope abundance and X‐ray photoelectron spectroscopic analyses. The photocatalyst (Pt@bpyCTF) with structural defects reduces CO2 to formic acid (FA) at a rate of 152 µmol h−1g−1 and a selectivity higher than 95% over CO and H2 in water under simulated solar light. The presence of amine defects and the immobilization of Pt cause improvement in the photocurrent density and CO2 capture capacity (≈8% by weight) despite the moderate surface area (0.54 cm3 g−1)of the photocatalyst. Theoretical models and density functional theory calculations are employed to investigate the possible CO2 reduction reaction (CO2RR) mechanisms. Considering the exceptional CO2 capture capacity and high FA production using only CO2‐bubbled water, this work highlights the great potential of nitrogen‐rich CTFs for photocatalyzed CO2RRs under green conditions. [ABSTRACT FROM AUTHOR]

The instability of molecular electrodes under oxidative/reductive conditions and insufficient understanding of the metal oxide-based systems have slowed down the progress of H2-based fuels. Efficient regeneration of the electrode's performance after prolonged use is another bottleneck of this research. This work represents the first example of a bifunctional and electrochemically regenerable molecular electrode which can be used for the unperturbed production of H2 from water. Pyridyl linkers with flexible arms (–CH2–CH2–) on modified fluorine-doped carbon cloth (FCC) were used to anchor a highly active ruthenium electrocatalyst [RuII(mcbp)(H2O)2] (1) [mcbp2− = 2,6-bis(1-methyl-4-(carboxylate)benzimidazol-2-yl)pyridine]. The pyridine unit of the linker replaces one of the water molecules of 1, which resulted in RuPFCC (ruthenium electrocatalyst anchored on –CH2–CH2–pyridine modified FCC), a high-performing electrode for oxygen evolution reaction [OER, overpotential of ∼215 mV] as well as hydrogen evolution reaction (HER, overpotential of ∼330 mV) at pH 7. A current density of ∼8 mA cm−2 at 2.06 V (vs. RHE) and ∼−6 mA cm−2 at −0.84 V (vs. RHE) with only 0.04 wt% loading of ruthenium was obtained. OER turnover of >7.4 × 103 at 1.81 V in 48 h and HER turnover of >3.6 × 103 at −0.79 V in 3 h were calculated. The activity of the OER anode after 48 h use could be electrochemically regenerated to ∼98% of its original activity while it serves as a HE cathode (evolving hydrogen) for 8 h. This electrode design can also be used for developing ultra-stable molecular electrodes with exciting electrochemical regeneration features, for other proton-dependent electrochemical processes. [ABSTRACT FROM AUTHOR]

This mini-review focuses on up-to-date advances of hybrid materials consisting of organic and inorganic components and their applications in different chemical processes. The purpose of forming such hybrids is mainly to functionalize and stabilize inorganic supports by attaching an organic linker to enhance their performance towards a target application. The interface chemistry is present with the emphasis on the sustainability of their components, chemical changes in substrates during synthesis, improvements of their physical and chemical properties, and, finally, their implementation. The latter is the main sectioning feature of this review, while we present the most prosperous applications ranging from catalysis, through water purification and energy storage. Emphasis was given to materials that can be classified as green to the best in our consideration. As the summary, the current situation on developing hybrid materials as well as directions towards sustainable future using organic-inorganic hybrids are presented. [ABSTRACT FROM AUTHOR]

Masked stereolithography printing can be used to produce functionalised magneto-responsive polymer structures. Magnetic filler additivation of the photopolymer enables the production of powerful and fast soft robotics. However, current approaches require high filler concentrations, reducing the mechanical properties and compromising the processability. In this study, FeNi nanoparticles were added to a photopolymer to take advantage of their soft magnetic response and high magnetisation. Field-assisted printing gives rise to magnetic anisotropy by arranging laser-synthesised FeNi nanoparticles into uniaxial magnetic strands of up to 500 μm length. Favoured by the small size and even distribution of the nanoparticles, only 0.02 wt% are needed to detect magnetic responsivity. Thus, the impact on the mechanical property is reduced while facilitating the control over the composite magnetic properties. The practical feasibility of the composites is demonstrated by actuating gripper and impeller structures which offer possibilities in applications like drug delivery and tissue engineering. [ABSTRACT FROM AUTHOR]

Photoluminescent carbon nanoparticles (CNPs), such as carbon dots (CDs), have attracted much attention owing to a unique set of properties, like high and tunable fluorescence. In this way, the use of carbon-rich lignin has been demonstrated to be a sustainable approach to producing a broad range of photoluminescent CNPs. However, the valorization of this complex polyphenol is limited when it comes to green and efficient ways of conversion. In addition, the existing solvothermal approaches using lignin often result in CDs with low photoluminescence, while flammable and/or toxic solvents are employed. Here, we depolymerized technical lignins, i.e. kraft and soda, through electro-reductive cleavage in two different sustainable media: deep eutectic solvent and levulinic acid. After depolymerization, lignin-derived monomers were generated, with a predominance of aryl ether and phenolic groups, which were further combined with 1,2- Phenylenediamine to produce N-doped CNPs in a solvent-free approach. Photoluminescent CNPs with varied sizes were generated (5–50 nm), which presented a wide photoluminescence emission, from blue to red, depending on solvent polarity. These results demonstrate a feasible and sustainable route for the solvent-free synthesis of photoluminescent CNPs using lignin-derived monomers as carbon source, which may find applications in a wide range of field. [ABSTRACT FROM AUTHOR]

The low stability of the electrocatalysts at water oxidation (WO) conditions and the use of expensive noble metals have obstructed large‐scale H2 production from water. Herein, we report the electrocatalytic WO activity of a cobalt‐containing, water‐soluble molecular WO electrocatalyst [CoII(mcbp)(OH2)] (1) [mcbp2−=2,6‐bis(1‐methyl‐4‐(carboxylate)benzimidazol‐2‐yl)pyridine] in homogeneous conditions (overpotential of 510 mV at pH 7 phosphate buffer) and after anchoring it on pyridine‐modified fluorine‐doped carbon cloth (PFCC). The formation of cobalt phosphate was identified only after 4 h continuous oxygen evolution in homogeneous conditions. Interestingly, a significant enhancement of the stability and WO activity (current density of 5.4 mA/cm2 at 1.75 V) was observed for 1 after anchoring onto PFCC, resulting in a turnover (TO) of >3.6×103 and average TOF of 0.05 s−1 at 1.55 V (pH 7) over 20 h. A total TO of >21×103 over 8 days was calculated. The electrode allowed regeneration of∼ 85 % of the WO activity electrochemically after 36 h of continuous oxygen evolution. [ABSTRACT FROM AUTHOR]

Quaternary metal oxynitride-based photoanodes with a large light transmittance are promising for high solar-to-hydrogen (STH) conversion efficiency in photoelectrochemical (PEC) tandem cells. Transparent substrates to support PEC water-splitting were fabricated using atomic layer deposition (ALD) to synthesize 30 and 60 nm GaN on SiC substrates. A generalized approach was used to grow a quaternary metal oxynitride, i.e. SrTaO2N thin film on the GaN/SiC substrates. The transparency above 60% in the wide solar spectrum highlights its availability of transmitting visible light to the rear side. A photocurrent onset at ca. −0.4 V vs. reversible hydrogen electrode (RHE) was achieved by the SrTaO2N/GaN/SiC photoanodes in a 0.1 M NaOH electrolyte under simulated solar irradiation. This paves the way for the construction of hierarchically nanostructured tandem PEC cells. This work demonstrates the viability of integrating ALD in constructing substrates for semi-transparent quaternary metal oxynitride photoanodes. [ABSTRACT FROM AUTHOR]

Breaking down lignin into smaller units is the key to generate high value‐added products. Nevertheless, dissolving this complex plant polyphenol in an environment‐friendly way is often a challenge. Levulinic acid, which is formed during the hydrothermal processing of lignocellulosic biomass, has been shown to efficiently dissolve lignin. Herein, levulinic acid was evaluated as a medium for the reductive electrochemical depolymerization of the lignin macromolecule. Copper was chosen as the electrocatalyst due to the economic feasibility and low activity towards the hydrogen evolution reaction. After depolymerization, high‐resolution mass spectrometry and nuclear magnetic resonance spectroscopy revealed lignin‐derived monomers and dimers. A predominance of aryl ether and phenolic groups was observed. Depolymerized lignin was further evaluated as an anti‐corrosion coating, revealing enhancements on the electrochemical stability of the metal. Via a simple depolymerization process of biomass waste in a biomass‐based solvent, a straightforward approach to produce high value‐added compounds or tailored biobased materials was demonstrated. [ABSTRACT FROM AUTHOR]

Research towards the production of renewable chemicals for fuel and energy industries has found lignin valorization as key. With a high carbon content and aromaticity, a fine-tuning of the depolymerization process is required to convert lignin into valuable chemicals. In context, model compounds have been used to understand the electrocatalyzed depolymerization for mimicking the typical linkages of lignin. In this investigation, 2-phenoxyacetophenone, a model compound for lignin β-O-4 linkage, was electro-catalytically hydrogenated (ECH) in distinct three-electrode setups: an open and a membrane cell. A deep eutectic solvent based on ethylene-glycol and choline chloride was used to pursue sustainable routes to dissolve lignin. Copper was used as electrocatalyst due to the economic feasibility and low activity towards hydrogen evolution reaction (HER), a side reaction of ECH. By varying the cell type, we demonstrate a simple ECH route for the generation of different monomers and oligomers from lignin. Gas chromatography of the products revealed a higher content of carbonyl groups in those using the membrane cell, whereas the open cell produced mostly hydroxyl-end chemicals. Aiming at high value-added products, our results disclose the cell type influence on electrochemical reductive depolymerization of lignin. This approach encompasses cheap transition metal electrodes and sustainable solvents. [ABSTRACT FROM AUTHOR]

The commercial breakthrough of Li‐ion batteries (LIBs) in the 1990s irrevocably shaped today's energy storage landscape, but the disposed batteries represent a growing hazard to the environment. One may initially assume that recycling processes are commendable technologies to ensure a counterbalance to LIBs manufacturing. However, the question remains whether current state‐of‐the‐art in LIBs recycling technologies can be considered as green. This problem is due to the application of toxic chemicals or the in situ generation of harmful substances during the recycling process. Besides the potential toxicity, current solutions are accompanied with intense energy consumption, causing carbon dioxide emissions, in disagreement with the circular economy principles. This review provides a critical assessment of both published research articles and patents to derive a broad picture on the sustainability of LIBs recycling technologies. Although the efficiency of industrially applied recycling technologies can exhibit a high overall efficiency, their general process design is generally based on waste reduction and downcycling. Contrariwise, sustainable recycling of LIBs should rely on circular processes ensuring upcycling of all materials toward zero waste and minimized energy utilization. Current solutions and expected development in LIBs recycling are presented, ranging from dismantling over components separation to application of bioderived materials. [ABSTRACT FROM AUTHOR]

We report the first magic-angle spinning (MAS) nuclear magnetic resonance (NMR) study on Sn(NCN). In this compound the spatially elongated (NCN)2− ion is assumed to develop two distinct forms: either cyanamide (N≡C–N2−) or carbodiimide (−N=C=N−). Our 14N MAS NMR results reveal that in Sn(NCN) the (NCN)2− groups exist exclusively in the form of symmetric carbodiimide ions with two equivalent nitrogen sites, which is in agreement with the X-ray diffraction data. The 14N quadrupolar coupling constant | C Q | $\vert {C}_{\text{Q}}\vert $ ≈ 1.1 MHz for the −N=C=N− ion in Sn(NCN) is low when compared to those observed in molecular compounds that comprise cyano-type N≡C– moieties ( | C Q | $\vert {C}_{\text{Q}}\vert $ > 3.5 MHz). This together with the information from 14N and 13C chemical shifts indicates that solid-state NMR is a powerful tool for providing atomic-level insights into anion species present in these compounds. The experimental NMR results are corroborated by high-level calculations with quantum chemistry methods. [ABSTRACT FROM AUTHOR]

Lignin nanoparticles (LNPs) are promising renewable nanomaterials with applications ranging from biomedicine to water purification. However, the instability of LNPs under acidic and basic conditions severely limits their functionalization for improved performance. Here, we show that controlling the degree of esterification can significantly improve the stability of lignin oleate nanoparticles (OLNPs) in acidic and basic aqueous dispersions. The high stability of OLNPs is attributed to the alkyl chains accumulated in the shell of the particle, which delays protonation/deprotonation of carboxylic acid and phenolic hydroxyl groups. Owing to the enhanced stability, acid‐ and base‐catalyzed functionalization of OLNPs at pH 2.0 and pH 12.0 via oxirane ring‐opening reactions were successfully performed. We also demonstrated these new functionalized particles as efficient pH‐switchable dye adsorbents and anticorrosive particulate coatings. [ABSTRACT FROM AUTHOR]