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Non-enzymatic electrochemical blood glucose sensors often suffer from issues such as requiring an alkaline environment, limited monitoring range, and poor anti-interference properties. Carbon substrates have been demonstrated to improve the performance of non-enzymatic sensors, but complex and energy-consuming manufacturing processes restrict their use. Herein, a simple and green approach for the preparation of 3D porous Au/Au-Pt networks (PAAPNs) is proposed using tissue paper for recycling as the nanomaterial substrate to deposit Au-Pt bimetallic nanoparticles. The unique structure of the PAAPNs sensor allows for low-potential operation (-1.0 V) with a wide monitoring range (-0.25 to 36 mM) in a neutral environment. Moreover, the sensor exhibited excellent selectivity (<10% response of interference) even without the use of an anti-interference outer membrane. Further investigation using density functional theory (DFT) simulation revealed the synergistic effect between Au and Pt in promoting glucose oxidation. Overall, this work provides a simple and low-carbon footprint method for creating carbon substrates from tissue paper for recycling, offering new opportunities for fabricating novel value-added nanomaterials for medical sensing applications. [ABSTRACT FROM AUTHOR]

The global market of fossil carbon-derived adipic acid (AA) was over 3 million tons in 2022, emitting 3.1 million tons of the potent greenhouse gas N2O. Alternative biomass-derived feedstocks offer a sustainable option to replace fossil carbon, but alternative pathways for AA synthesis are also required to curb the substantial emissions associated with the process. A novel and sustainable approach to synthesize AA is by coupling biomanufacturing and electrocatalysis. Biologically-produced cis,cis-muconic acid (ccMA) from sugars and lignin monomers has recently gained significant attention as a precursor to AA, as it can be electrochemically hydrogenated to AA using water-derived (instead of fossil-derived) hydrogen and electricity generated from wind energy. For the first time in literature, we demonstrate appreciable electrochemical production of AA using supported palladium nanoparticles. The performance of this system contrasts with that of palladium foil or platinum-based catalysts, which produced little AA. Density functional theory calculations on model surfaces of palladium and platinum suggest that the reduction of ccMA to trans-3-hexenedioic acid occurs through an outer sphere proton-coupled electron transfer mechanism, while subsequent reduction to AA preferentially occurs on surface terrace sites. Our calculations also explain the exceptional performance of palladium nanoparticles compared to palladium- and platinum-based foils, attributing the more favorable activation energy barriers found on palladium terraces to the relatively moderate binding strength of adsorbed species. These results suggest structure-sensitive catalyst design strategies that maximize the exposure of terrace atoms for further improvement of the ccMA electrochemical hydrogenation process. [ABSTRACT FROM AUTHOR]

The electrochemical selective oxidative transformation of lignin feedstocks into valuable oxygenated aromatics is essential to establish a sustainable biorefinery. In this study, we used a rhombohedral ZnIn2S4 (R-ZIS) electrocatalyst to realise the efficient anodic cleavage of C-O bonds in benzyl phenyl ether (BPE), an a-O-4 lignin model compound, to a series of industrially relevant oxygenated mono-aromatics. The reaction occurred at +2 VAg/AgCl, 65 °C, and atmospheric pressure. In optimised conditions, the reaction achieved over 99% conversion rate with a Faraday efficiency of 51.6% at 91.3% conversion of BPE, that is greater than most known electrocatalytic oxidative cleavage examples. The ZnIn2S4 electrocatalyst was deposited on a carbon cloth support, and its structural properties and surface morphology were extensively investigated. Systematic potential controlled electrolysis coupled with 18O isotopic labelling confirmed that C-O scission occurred exclusively between the benzylic carbon and phenolic oxygen. Furthermore, substrate competition studies were conducted to compare the electrocatalytic performance of the R-ZIS catalyst with that of its structural analogue, hexagonal ZnIn2S4, in terms of BPE and monoaromatics conversion. The experimental results were supported by density functional theory calculations. The substrate scoping study revealed the suitability of the R-ZIS induced electrocatalytic system for a variety of substituted a-O-4/ß-O-4 model dimers. Overall, this work demonstrates an efficient anodic process that can enable the atom-efficient valorisation of lignin to produce oxygenated aromatics. The proposed approach can complement the numerous existing reductive lignin cleavage methods. [ABSTRACT FROM AUTHOR]

Halogenated nitroarenes' hydrogenation on metal-based catalysts without dehalogenation to synthesize halogenated amines is a research challenge. Herein, using a covalent organic framework (COF) as a support and benefiting from strong metal-support interactions (SMSIs), ultrafine Pt nanoparticles were successfully anchored on a polyimide-based covalent triazine framework, to construct an electron-rich Pt active site-based catalyst (Pt/TAPT-COF). The electronic regulation from the COF contributed to both the selective hydrogenation of halogenated nitrobenzenes and the tandem hydrogenation-coupling reaction of halogenated nitrobenzenes with aldehyde compounds to synthesize halogenated amines with high selectivity under mild reaction conditions. According to density functional theory calculations, the hydrogenation of halogenated nitrobenzene is exothermic with strengthened absorption, confirming the existence of SMSIs to explain the high activity of Pt/TAPT-COF in hydrogenation reactions. Thus, this work provides a facile strategy to fabricate an electron-rich Pt-based catalyst enabled by SMSIs to selectively catalyze the synthesis of halogenated anilines and halogenated secondary amines. [ABSTRACT FROM AUTHOR]

The development of highly efficient and environment friendly methods for arsenic pollution treatment has attracted special attention. Herein, a new polyoxometalate-thiacalix[4]arene-based metal-organic complex [Ag2L(HL)][PW12O40]·2C2H5OH·2CH3CN (1) (L = thiacalix[4]arene-based ligand) was synthesized and applied for BiVO4 (BVO) surface modification to efficiently enhance the simulated sunlight-driven photoelectrocatalytic oxidation of arsenic(III). Compared with the pristine BVO, the removal efficiency of arsenic(III) was drastically increased to 312% at 0.6 V with the optimized 1@BVO photoanode (B1-20) versus the saturated calomel electrode (SCE) under the simulated sunlight (100 mW cm-2). The removal efficiency of arsenic(III) (25 mg L-1) with B1-20 was up to 100% within 40 min with a faradaic efficiency of 45%. More importantly, electron spin resonance measurements and reactive species trapping experiments demonstrated that the Z-scheme heterojunction formation of 1 plays a key role in the enhanced photoelectrocatalytic performance of 1@BVO. Furthermore, density functional theory (DFT) calculations were used to investigate the relationship between the photoelectrocatalytic properties and the structure of 1. This work developed a new photoelectrocatalytic application for the polyoxometalate-thiacalix[4]arenebased metal-organic complexes by their efficient combination with BVO. [ABSTRACT FROM AUTHOR]

Multicomponent reactions (MCRs) have demonstrated enormous potential in the direct and single-step synthesis of chemical entities with structural diversity. However, the photochemical MCR approach for the construction of N-heterocycles, particularly functionalized ones, from non-heterocyclic synthons remains relatively unexplored. Herein, we report a modular assembly of CF3-modified 3,4-dihydroquinazolinones from basic building blocks using a one-pot light-driven multicomponent approach. In this protocol, the latent capability of 1-(2-acetylphenyl)-3-phenylurea to reach a reactive triplet state upon energy transfer (EnT) activation while successfully triggering intramolecular cyclization is disclosed. Medicinally relevant 3,4-dihydroquinazolinones could be feasibly synthesized from commercially available 2-aminoacetophenone, p-tolyl isocyanate, and Togni's II, offering a metal-free construction with broad functional group tolerance. Mechanistic investigations revealed EnT mediated intramolecular cyclization and single electron transfer (SET) mediated hydroxytrifluoromethylation cascade reactions in this novel process. Density functional theory calculations illustrated the energy landscape of this photoinduced transformation. [ABSTRACT FROM AUTHOR]

The electronic state of metallic centers plays a crucial role in electrocatalytic reactions such as oxygen evolution reaction (OER), which usually require high-valence transition metallic centers. Herein, we propose an organic ligand coordination strategy to modulate the electronic state of metallic centers in NiFe LDH, by introducing three different organic linkers including 2,6-naphthaleneducarboxylic acid, 4,4′-bipyridine, and 1H-1,2,3-triazole on the surface of NiFe LDH to derive atomic-layered metal–organic framework (NiFe LDH@MOF). Experimental results indicate that the electronic structure of metal centers in the composite was modified after the coordination of organic linker, among which the most amount of high-valence state was for Fe species in the 1H-1,2,3-triazole involved catalysts (NiFe LDH@MOF-3). Density functional theory (DFT) calculations further demonstrate that the 1H-1,2,3-triazole linkers around Fe centers optimized the d-band center together with the beneficial Gibbs free energy of the intermediate. Therefore, NiFe LDH@MOF-3 exhibited a superior electrocatalytic OER performance with a low overpotential of 242 mV to achieve a current density of 100 mA cm−2, a small Tafel slope of 32.3 mV dec−1. This work provides a general strategy for the modulation of the electronic structure of metallic centers using organic linker coordination to achieve a high-performance electrocatalyst. [ABSTRACT FROM AUTHOR]

Biomass appears to be a potential candidate for the preparation of porous carbon materials with wide applications for catalytic fields due to its low price, green sustainability and natural hierarchical porous structure. Here, we designed a novel NixCuy/BC catalyst with a unique hollow sphere structure derived from a biomass puffball, which exhibited a superior catalytic transfer hydrodeoxygenation of VAN to value-added MMP products with an ∼100% vanillin (VAN) conversion and over 88% selectivity of 2-methoxy-4-methylphenol (MMP) products in the absence of additional hydrogen. The good catalytic activity performance of the NixCuy/BC catalysts was attributed to the NiCu alloy with a unique hollow sphere structure, high dispersion and electron transfer. Density functional theory (DFT) calculation results also indicated NiCu alloy as the main catalytic sites. This work not only provided a cheap and efficient hydrodeoxygenation catalyst for VAN hydrodeoxygenation, but also offered new insights for designing novel and unique biomass-based carbon materials for biomass utilizations or other widespread applications. [ABSTRACT FROM AUTHOR]

Sulfide compounds offer promising alternatives for electrocatalysts in water splitting, thanks to their diverse nature, intrinsic activities, affordability, and abundance in the Earth's crust. However, the limited active sites, hindered substance transport, larger particle size, and structural collapse restrict their performance in the electrolysis of water. In order to achieve a dual-functional catalyst with multiple catalytic sites, it is often necessary to construct heterogeneous or composite structures. However, this typically leads to an increase in catalyst resistance and also affects its operational stability. In response, we successfully prepared a high-entropy sulfide (ZnCoMnFeAlMg)9S8 through a low-temperature solvothermal method. This approach resulted in a reduction in grain size and a doubling of the specific surface area. The high entropy not only maintains the stability of the structure but also induces electron interactions within the catalyst through the interactions of multiple metals. This exposure of more active sites enables the realization of a dual-functional catalyst with multiple catalytic sites within a single structure. In addition, the increased presence of high-valence Fe and Ni ions promotes the chemisorption of intermediates, facilitating electron transfer during the reaction process. Benefiting from this multi-scale regulation strategy, the (ZnCoMnFeAlMg)9S8 displays an ultralow overpotential of 1.39 V at 10 mA cm−2 and a small Tafel slope of 35.3 mV dec−1. Density functional theory calculations indicate that high entropy can significantly modulate the local charge distribution and electronic properties of sulfides, thereby achieving optimal adsorption energy and reducing the potential energy barrier for hydrolysis. This study introduces a fresh approach to the functionalization of high entropy nanomaterials, while simultaneously enhancing the performance of water splitting catalysts. [ABSTRACT FROM AUTHOR]

The selective photocatalytic reduction of CO2 to CH4 remains a challenge because there is a need for not only strong adsorption sites for the intermediates, but also optimal proton-feeding sites on the photocatalyst surface. Herein, a synergistic dual-site function between in situ-generated Ni0 and Ni2P on carbon nitride nanosheets (CN) for photocatalytic reduction of CO2 to CH4 is presented. The highest CH4 production rate of 69.03 μmol g−1 h−1 is achieved on Ni2P/CN-0.5 in an aqueous suspension. Detailed analyses show that the promotion of CH4 is closely correlated with the formation of Ni0 sites due to light irradiation, which is confirmed by tracking the compositions of Ni2P/CN-0.5 through XPS and HRTEM characterization. Density functional theory calculations have been combined with CO-TPD and in situ FTIR spectra to reveal the synergy between in situ-generated Ni0 sites and Ni2P. It shows that the Ni0 sites can stabilize the key intermediate *CO, while the Ni0–Ni2P interface can promote *H transfer from Ni2P to Ni0. Therefore, the CO intermediates are rapidly protonated to form CHO* instead of being desorbed from the surface to produce CO, and subsequently CHO* will be converted into CH4. This work demonstrates a new strategy of designing highly efficient photocatalysts with synergistic catalytic sites for CO2 conversion to hydrocarbons. [ABSTRACT FROM AUTHOR]

The development of safe, economical and highly efficient oxidation systems for the production of chemicals from biomass remains a significant and challenging target. Here, we first found a unique air-assisted reaction mechanism for the non-pressurized oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) using dimethylsulfoxide (DMSO) as an O-donor over CoZrNC-MCM, which affords exceptional productivity among all non-noble catalysts. The combination of control experiments and density functional theory (DFT) calculations reveals that the air-assisted DMSO oxidation pathway is activated by the co-adsorption of DMSO and O2 on Co-(pyrrolic N–C) pairs of CoNC-MCM. ZrNC species in CoZrNC-MCM will be thermally disintegrated to release ZrO2+ and provide the corresponding cation vacancies that might be able to capture Co atoms to form additional Co-(pyrrolic N–C) active pairs, resulting in the increase of catalytic activity. The released ZrO2+ is well dispersed over Al-MCM-41 in the form of zirconia, which contributes to the dehydration of fructose to HMF. In this way, a one-step approach for synthesizing DFF from fructose is achieved by the cooperation of zirconia and Co-(pyrrolic N–C) pairs over CoZrNC-MCM. [ABSTRACT FROM AUTHOR]

Fast pyrolysis of lignocellulosic biomass is a promising approach for producing biofuels and renewable chemicals, but the resultant bio-oil quality and diverse product distributions limit its widespread adaptation. Concurrently, the accumulation of waste plastics in the environment, particularly polyolefin thermoplastics, is becoming a growing threat. Co-pyrolysis of biomass with hydrogen-rich thermoplastics has shown promise for producing high-quality bio-oils, presenting an attractive solution to waste management. However, a molecular-level understanding of the synergy of the two components in the molten phase during co-pyrolysis is still lacking. In this work, we report the discovery of catalytic and inhibitory effects on cellulose fast pyrolysis caused by noncovalent interactions (NCIs) induced by molten plastics. Our microreactor experiments demonstrated that selectivity toward cellulose-derived anhydrosugars, small oxygenates, or furans increased due to the presence of polyketone, polyethylene glycol, or polystyrene, respectively, which are three thermoplastics with distinct functional groups. Density functional theory calculations reveal that key cellulose pyrolysis pathways leading to major products are catalyzed or inhibited due to perturbations of transition state geometries and partial charges caused by the NCIs induced by plastic functional groups. This discovery offers insights and opportunities for tuning cellulose fast pyrolysis via NCIs using a new family of unconventional molten plastic catalysts or inhibitors. [ABSTRACT FROM AUTHOR]

The accumulation of gypsum waste (GW), such as flue gas desulfurisation gypsum and phosphogypsum, which remains in regulated stacks occupying considerable land resources, is causing significant environment problems worldwide. A promising strategy for treatment and recycling of GW is to convert GW into higher-valued anhydrite, but the traditional energy-intensive calcination method significantly increases the cost of recovery. Here, we report the first solid-like dehydration of gypsum to produce anhydrite at room temperature. Specifically, a 39 nm thick sulfuric acid film (NSF) was fabricated to extract water of crystallization from gypsum and simultaneously enable a phase transformation from gypsum to anhydrite via recrystallization. Using density functional theory calculations, we obtained the activity (0.025) of crystalline water in gypsum, which is higher than the corresponding value in NSF, so that the dehydration can occur spontaneously. Using our developed kinetic model, we attributed the acceleration of this transformation to the lower nucleation potential (56 kJ mol−1) of anhydrite and the more efficient transfer of the mass (several orders of magnitude higher than that for heating gypsum powders) required for growth. This model allows prediction of nucleation and growth contributions from kinetic data for any given recrystallization system. This work not only demonstrates a new type of recrystallization reaction driven by a nano-film reservoir, which differs from bulk solution–solid and gas–solid reactions but also provides a promising strategy for energy-efficient recycling of anhydrite from gypsum waste. [ABSTRACT FROM AUTHOR]

Metal oxide catalysts' performance depends on their crystal structure, including the surface arrangement and coordination of metal cations and oxygen anions on the exposed facets. Here, we fabricated Co3O4 nanocrystals (NCs) with predominantly exposed (110), (111), (112), and (114) facets in the shapes of nanorod (Co-R), hexagonal nanoplate (Co-H), nanolaminar (Co-L), and nanoparticle (Co-P), respectively. The Co3O4 NC with exposed (114) high-index facet exhibits the highest 5-hydroxymethylfurfural (HMF) electrocatalytic activity, while the Co3O4 NC with exposed (112) shows the lowest activity. Both density functional theory (DFT) calculations and experiments reveal that the primary factor impacting the catalytic performance of Co3O4 NCs is the difference in HMF adsorption energy on various crystal facets. By doping Cr into Co3O4 (114), we tuned the adsorption energy of HMF to an optimal level, thereby achieving the best catalytic performance. Based on this, the adsorption behavior of other aldehyde–alcohol organic small molecules was also evaluated, and the linear relationship between adsorption strength and catalytic activity was confirmed. This work demonstrates that adjusting the exposed crystal facets of Co3O4 can alter the adsorption and catalytic capabilities of aldehyde–alcohol organic small molecules. It also provides explicit knowledge that could improve our understanding of facet-dependent reactions for other metal oxide catalysts. [ABSTRACT FROM AUTHOR]

For effective overall water splitting (OWS) in alkaline media, a novel Ru-doped bimetal oxide (Ru-NiCo2O4) catalyst deposited onto a conductive nickel foam (NF) is fabricated by a multi-step hydrothermal reaction, ion exchange, and subsequent annealing process. The distinctive 3D nanoneedle-like arrays not only provide an even distribution of Ru decorated NiCo2O4, but also expose additional active sites, facilitating electron transport and improving reaction kinetics. Besides, density functional theory (DFT) studies elucidate the electronic structure regulation in Ru-NiCo2O4 and the modification of the d-band center optimizes H* adsorption energy, which considerably increased the hydrogen production efficiency. Considering the aforementioned advantages, the as-prepared Ru-NiCo2O4 electrocatalyst exhibits greatly improved catalytic activity, requiring only 25 mV and 249 mV at 10 mA cm−2 for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, as well as robust stability. Amazingly, the Ru-NiCo2O4 electrode in a two-electrode alkaline electrolyzer only needs 1.55 V to produce 10 mA cm−2, making it more efficient than the commercial RuO2‖‖Pt/C electrode (1.62 V). More importantly, 0.33 M urea only needs a low voltage of 1.427 V to drive the urine-mediated electrolysis, which is about 123 mV less than the urea-free electrolysis cell. This work presents an effective electronic structure engineering approach based on heteroatom doping that may be extended to design and fabricate novel high-performance OWS catalysts. [ABSTRACT FROM AUTHOR]

Investigation of catalytic hydrogenation of CO2 to CO via the reverse water-gas shift (RWGS) was undertaken using Ni/SiO2-based catalysts. Among the array of catalysts tested, the Ni/SiO2 catalyst derived from the reduction of silicalite-1-encapsulated, ligand-protected Ni2+ (Ni0.2@S-1-red) exhibited promising performance. This catalyst demonstrated a CO2 conversion rate approaching the equilibrium conversion of RWGS, a selectivity for CO exceeding 99%, and a high space time yield of CO (9.7 mol gNi -1 h-1). The outcomes observed can be attributed to several factors, such as the highly dispersed Ni0 and Niδ+ species, as well as the presence of bridging oxygen of the Ni-O-Si structure, on which CO2 can be adsorbed moderately. The moderately bonded CO2 on Ni0.2@S-1-red allows for the efficient desorption of its reduced intermediate, i.e. *CO, resulting in the generation of gaseous CO at a rapid rate, consequently preventing its deep hydrogenation to CH4. Complementary Density Functional Theory (DFT) calculations were performed and revealed that CO molecules have poor adsorption and higher adsorption energy on the Ni@S-1 surface compared to the S-1 surface. This supports the rapid desorption of *CO and the observed high selectivity of CO. Moreover, the structure-activity correlation analysis further supports the claim of Ni0.2@S-1-red as a promising RWGS catalyst. [ABSTRACT FROM AUTHOR]

The Co-based heterojunction is regarded as an efficient material for the oxygen evolution reaction (OER), but the synthesis is still time- and labor-consuming, and environmentally unfriendly. Herein, we propose a green and facile L -lysine-induced strategy for the successful synthesis of porous CoS/Co3O4 nanoframes (NFs). L -Lysine played a pivotal role in facilitating the formation of the stable Co(OH)2 nanosheet precursor, which was subsequently in situ converted into CoS/Co3O4 NFs through the sulfuration treatment. The resulting CoS/Co3O4 NFs showed a low overpotential of 304 mV at 10 mA cm−2 and remarkable long-range durability in 1.0 M KOH for the OER. The rechargeable Zn–air battery exhibited high charge–discharge cycling stability (>120 h) with CoS/Co3O4 NFs + Pt/C as an air cathode. Density functional theory calculations demonstrated that the charge density of the CoS/Co3O4 heterostructure can be redistributed by rebalancing the Fermi level after the contact between CoS and Co3O4, potentially modulating the pristine catalytic properties of single components. This work provides a facile and green synthesis strategy for developing efficient Co-based catalysts in sustainable energy conversion devices. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR) is deemed a sustainable energy source; however, developing green, earth-abundant, and efficient noble-metal-free catalysts for efficient ORR in different media remains a grand challenge. Herein, we present a scalable, facile, environmentally benign, and one-pot strategy for the fabrication of eco-friendly nitrogen-enriched graphitic-like hierarchical porous sub-100 nm carbon (denoted as N-HMPC) nanocapsules with controllable N-content for ORR. The synthesis route is based on in situ organic-organic self-assembly of Pluronic F127 copolymer micelles and resorcinol–melamine–formaldehyde in the presence of a silica template followed by carbonization and eroding the silica core. The as-formed N-HMPC nanocapsules have a core–shell morphology (∼84 nm), hierarchical porosity, high surface area of (790 m2 g−1), and tunable nitrogen content (9–25%). Intriguingly, N-HMPC nanocapsules exhibit an analogous ORR activity to the commercial Pt/C catalyst (20% Pt) in the alkaline and acidic electrolytes, besides superior durability and inimitable tolerance to methanol and CO poisonings due to the hollow core–shell architecture and abundant nitrogen. A judicious combination of experimental and density functional theory (DFT) simulations delineated the ORR pathway and mechanism for N-HMPC in acidic and alkaline electrolytes. The presented approach may open new avenues for the rational design of metal-free green electrocatalysts for ORR. [ABSTRACT FROM AUTHOR]

The hydroboration of alkynes with bis(pinacolato)diboron (B2pin2) using H2O or untreated H2O as a solvent is a challenging task. This work reports the aqueous N-heterocyclic carbene (NHC)-catalyzed hydroboration of alkynes with B2pin2, in which a wide range of alkynes with different functional groups are tolerated. The proposed NHC active species are formed through a nonclassical strategy in contrast to the traditional method involving deprotonation of the imidazolium salts in the presence of a base. The proposed NHC-catalyzed hydroboration process can be performed using untreated H2O as a solvent under an air atmosphere in the absence of exogenous bases. Mechanistic investigations, including control experiments, Fourier transform infrared spectroscopy, and density functional theory calculations revealed that the NHC generated in situ is the true active species. Moreover, an in situ generated diboron-NHC adduct, which acts as a reservoir of NHC and is critical for the stability of NHC in aqueous media, was isolated and fully characterized. [ABSTRACT FROM AUTHOR]

As the richest aromatic renewable resource, lignin has attracted significant attention for fabricating various materials. However, due to lignin's structural complexity, an effective and facile structural modification strategy remains a substantial challenge. Herein, we have successfully applied photoinitiated reversible addition–fragmentation chain transfer (RAFT) as a versatile tool to synthesize amphiphilic lignin copolymers with lignin derivatives as the macroinitiator. The experimental and density functional theory analysis systematically investigated the photopolymerization kinetics, proving excellent control over molecular weights. Additionally, 1H NMR and FT-IR analyses confirmed the well-designed structures. Moreover, the structures of copolymers were tunable by simple variations of monomer structures. Finally, the self-assembly of the synthesized copolymers into nanoparticles was explored, together with the potential applications as Pickering emulsion stabilizers. We believe that this work will offer a facile and green approach to synthesize lignin-based novel copolymers and further expand its applications. [ABSTRACT FROM AUTHOR]

2,4,6-Trinitrotoluene (TNT) degradation is of interest in environmental remediation, demilitarization, and national security. Electrochemical TNT reduction to 2,4,6-triaminotoluene is potentially energy efficient and operable at ambient conditions. Determining an elementary reduction mechanism and rate limiting steps is needed to rationally develop TNT electroreduction catalysts. Density functional theory methods determine the TNT reduction mechanism for non-catalyzed and late-transition metal catalyzed paths. The non-catalyzed mechanism is limited by slow initial NO2 group reduction. The outer-sphere mechanism is more competitive to electrocatalytic reduction on Au (111) and Fe (110) surfaces, which wasn't observed in our previous work on nitrobenzene electroreduction. An inverse tradeoff between the initial reduction of the NO2-R* group and reduction of surface hydroxyls suggests relative catalytic activity can be tuned by modulating O* affinity. Metal surfaces with intermediate O* affinity (Cu, Pt, Pd, and Ir) are predicted to be the most active late transition-metals towards TNT reduction. We extend our investigation to bimetallics and partially reduced Fe2O3 (0001) surfaces. [ABSTRACT FROM AUTHOR]

Improper disposal of large quantities of crustacean shell waste from the food industry has caused serious environmental problems and waste of resources. Shell biorefinery is an emerging concept that upcycles the major components of crustacean shell waste, such as chitin, into value-added chemicals and materials. Producing biomass-derived 5-hydroxymethylfurfural (HMF) has been a hot topic over the past decades, while efficient conversion of shell-derived chitin into HMF is not available due to its water-insoluble and chemically-stable features. Herein, we develop a sustainable and efficient HMF production route from chitin. Chitin was treated with formic acid under mild conditions to synthesize formylated chitin (FC), which was subsequently converted to HMF in dimethyl sulfoxide (DMSO)–H2O media. Results showed that FC achieved a 53.2% HMF yield at 160 °C for 10 min catalyzed by AlCl3 in the co-solvent system (DMSO : H2O = 4 : 1, v/v), which is 11 times higher than the yield obtained from chitin under the same condition. The grafted formyl groups on FC significantly enhanced its noncovalent interactions with DMSO molecules, enhancing the accessibility and reactivity for HMF production. The reaction mechanisms were proposed and simulated with density functional theory calculations, and the intramolecular hydrogen migration is the rate-determining step in the reaction pathways. This study highlights a green and simple approach for chitin valorization. [ABSTRACT FROM AUTHOR]

Herein, a straightforward and efficient route for the construction of dual α,β-C(sp3)–H functionalized cyclic N-aryl amines using a combination of electrocatalysis and iron catalysis is disclosed. This method is achieved by multiple single electron oxidations and is carried out in an operationally simple manner with high chemo- and site-selectivity, setting the stage for the challenging multiple site selective C–H functionalization. The mechanism is supported by a variety of experimental probes and theoretical investigations, including cyclic voltammetry tests, a bipolar ultramicroelectrode (BUME) methodology combined with nano-electrospray ionization mass spectrometry, and density functional theory calculations. [ABSTRACT FROM AUTHOR]

Achieving the green conversion of propargylic amines with CO2 is highly desirable but challenging. Noble-metal catalysts, co-catalysts, harsh operating reaction conditions (high temperatures and high pressures) and toxic solvents are usually required to catalyze this reaction. Herein, a noble-metal-free composite material Cu2O@MIL-101(Cr)-DABCO (DABCO = 1,4-diazabicyclo[2.2.2]octane) was rationally fabricated by successively introducing DABCO and Cu2O into the metal-organic framework (MOF) MIL-101(Cr) via a stepwise assembly strategy. The resultant composite Cu2O@MIL-101(Cr)-DABCO exhibits excellent solvent stability and can effectively catalyze the cyclization of propargylic amines and CO2 with good reusability (=5 times) as a result of the great confinement for Cu2O nanoparticles (NPs) inside the MOF and the strong coordination interaction between DABCO and the MOF. Furthermore, the reaction mechanism was clearly illustrated by NMR, FTIR, 13C isotope labeling experiments and density functional theory (DFT) calculations, in which the synergistic effect between Cu2O and DABCO within MIL-101 (Cr) can greatly activate the CuC and N-H bonds of propargylic amines and thereby boost the reaction. Importantly, this is the first report of a noble-metal free catalyst that can catalyze the green conversion of CO2 with propargylic amines in the absence of a co-catalyst and solvent under room temperature and atmospheric pressure conditions. [ABSTRACT FROM AUTHOR]

Direct synthesis of 2,1-benzisoxazole and its related N-heterocyclic compounds via a chemoselective reductive heterocyclization route, which involves hydrogenation and subsequent intramolecular cyclodehydration steps, is a viable and attractive approach. However, the efficient transformation of the feedstocks using hydrogen as a hydrogen source at ambient temperature and atmospheric hydrogen pressure remains a great challenge. Herein, we reported a MgO-incorporated porous carbon composite (MgO@C) stabilized subnanometric Pt cluster (Pt/MgO@C) catalyst prepared by annealing a Mg-containing metal–organic framework, Mg-MOF-74, followed by impregnation of a Pt precursor and further reduction treatment strategy. The as-prepared Pt/MgO@C with ultralow Pt loading (0.078 wt%) exhibited superior catalytic performance for synthesizing 2,1-benzisoxazole derivatives by the reductive heterocyclization methodology. Excellent catalytic activity (conversion ≥ 99%), high chemoselectivity (≥92%), good stability (8 cycles), and broad functional group tolerance (10 substrates) were achieved under very mild conditions (1 bar hydrogen pressure at 303 K) over the developed Pt/MgO@C. Control experiments indicated that a proper amount of basic sites, subnanometric Pt clusters, and a close contact between them synergistically contributed to the extraordinary performance of Pt/MgO@C. Density functional theory calculations showed that the high activity and chemoselectivity of Pt/MgO@C stemmed from the active interfacial sites of Pt/MgO@C simultaneously activating the H2 and substrate, where the formed stable hydroxyl groups contributed to the enhancement of activity. The combined experimental and theoretical approach identified the formation of the –NO and –NHOH groups during the hydrogenation process, and the former corresponds to the rate-determining step. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of CO2 into liquid fuels such as ethanol, powered by renewable electricity, is an efficient strategy for CO2 utilization to produce high value-added products. In this work, we discovered that the primary C2+ product could be switched from gaseous ethylene to liquid ethanol by directly increasing the CO2 pressure when Cu2O@Cu with a hollow sphere morphology was adopted as the catalyst. The faradaic efficiency (FE) of ethanol reached as high as 36.6% at a low overpotential of −1.0 V vs. Ag/AgCl (−0.48 V vs. RHE) at 100 bar, which was 4.6 times higher than that of 1 bar. Moreover, faster kinetics and lower overpotential for ethanol formation were obtained at high CO2 pressures. In situ Raman spectroscopy studies at different pressures in combination with density functional theory calculations demonstrated that the *CO surface coverage was increased significantly at increased CO2 pressure, which is responsible for facilitating ethanol formation during the electrochemical CO2RR. This study provides a novel and promising strategy for the selective production of ethanol on Cu-based catalysts by facilely adjusting the CO2 pressure. [ABSTRACT FROM AUTHOR]

CO2 electroreduction into valuable products holds great promise for energy supply and environmental remediation but remains a challenge due to the lack of high-performance electrocatalysts. Herein, we developed an efficient strategy to prepare highly active Fe single-atom catalysts (Fe–N5/Fe–N6) by tuning the coordination number of Fe with N towards CO2 electroreduction. The faradaic efficiency of CO for Fe–N5 exceeded 90% ranging from −0.35 to −0.65 V versus the reversible hydrogen electrode (vs. RHE) towards CO2 electroreduction. The turnover frequency of CO for Fe–N5 reached 5006 h−1 at −1.05 V vs. RHE, which was 3.8 times that (1324 h−1) of Fe–N6. Besides, CO was generated at an overpotential as low as 50 mV over Fe–N5, smaller than that (90 mV) over Fe–N6. Density functional theory calculations demonstrated that Fe–N5 facilitated the adsorption and activation of CO2 to form the *COOH intermediate, thus leading to superior selectivity and activity for CO2 electroreduction. [ABSTRACT FROM AUTHOR]

Non-isocyanate polyurethanes (NIPUs) from renewable resources have attracted much attention owing to their significant benefits towards sustainable development and green production. However, the low molar mass and poor mechanical properties of NIPUs greatly restrict their large-scale production and practical application as alternatives to conventional polyurethanes. In this study, a series of bio-based carbonated linseed oil (CLSO) films were synthesized via the carbon dioxide (CO2) coupling reaction of epoxidized linseed oil (ELSO) followed by efficient conversion into novel renewable NIPU thermosetting networks by curing CLSO with different diamines. In the coupling reaction between ELSO and CO2 (denoted as CO2@ELSO), the reactivity of epoxy groups at different sites on the ELSO was revealed by density functional theory (DFT) calculations. Furthermore, the reaction conditions for CLSO and NIPU films were optimized to achieve high atom efficiency and tailorable performance. The tensile strength of the resulting NIPU films was high up to 69.2 MPa and the elongation at breaking could be maintained at 15.4% due to their high crosslinking density and hydrogen bonding content. The novel bio-based NIPU materials developed in this work demonstrate various advantages, including excellent mechanical properties and thermal stability, which could find various applications in coatings, adhesives, elastomers and other industries. [ABSTRACT FROM AUTHOR]

An ideal strategy for the management of greenhouse gas carbon dioxide (CO2) and surplus industrial product-glycerol (Gly) is to convert them into the valuable glycerol carbonate (GC). However, conventional conversion processes rely on high CO2 pressure and reaction temperature. In this work, a series of easily prepared protic ionic liquids (ILs) were studied for the one-pot synthesis of GC using CO2, Gly, and styrene oxide (SO). A 94% yield of GC was obtained with the catalysis of 1,8-diazabicyclo[5.4.0]undec-7-enenium iodide (HDBUI) under atmospheric pressure at 45 °C. Experimental results and density functional theory (DFT) calculations suggest that the high catalytic activity of HDBUI is attributed to the strong nucleophilicity and substrate activation afforded by the synergistic effect of the protic HDBU+ cation and I− anion. In addition, high GC yields were also obtained when simulated flue gas and crude Gly were used as substrates. [ABSTRACT FROM AUTHOR]

The direct catalytic oxidation of alcohols to carboxylic acids is very appealing, however, economic and environmentally friendly catalytic systems should be further explored from the aspect of less waste production and a convenient procedure. Herein, we display a structurally defined inorganic ligand-supported iron compound, (TBA)3[FeMo6O18(OH)6] (simplified as FeMo6), which could be used as a heterogeneous molecular catalyst in water for this conversion, with oxygen as the terminal oxidant and KCl as an additive. The oxidation of various alcohols (aromatic and aliphatic) could be achieved in almost all cases under mild conditions and provided the corresponding carboxylic acids in high yields, including some active molecular entities and natural molecules with carboxyl structures. Detailed studies showed that chloride ions could combine with the molecular catalyst FeMo6 to form a supramolecular aggregate FeMo6·Cl, which could effectively catalyze the reaction, relying on the synergistic effect of chloride ions and FeMo6. Control experiments, 1H NMR studies and density functional theory (DFT) calculations showed that the oxidation reaction might involve a free radical pathway. [ABSTRACT FROM AUTHOR]

Owing to the myriad of applications that amides have, hydration of nitriles has emerged as one of the most preferred atom-efficient synthesis methods. Being kinetically slow, this strategy requires some efficient catalysts. Herein, we discovered choline hydroxide as an environmentally benign, metal-free and inexpensive catalyst for the hydration of aromatic and heteroaromatic nitriles on/in water with excellent yields. All the reactions proceeded under mild/moderate conditions, facilitated by the hydrogen bonds between the catalyst and the reactant or intermediate. Density functional theory (DFT) studies were used to propose the plausible reaction mechanism, which was further corroborated with kinetics measurements using quantitative 19F NMR spectroscopy, thereby revealing the presence of H-bond mediated catalysis which brought down the activation energy barrier even lower than those in previous reports on using H2SO4 or Ru(OH)x/Al2O3 as catalysts. This work offers an "on/in-water" reaction strategy for the efficient hydration of nitriles and will pave the path towards novel routes for the commercial synthesis of amides. [ABSTRACT FROM AUTHOR]

Biodiesels produced from renewable sources exhibit superior fuel properties and renewability and they are more environmentally friendly than petroleum-based fuels. In this paper, a three-step transesterification, catalyzed by a pyridinium-based Brønsted acidic ionic liquid (BAIL), for biodiesel production was investigated using density functional theory (DFT) calculations at the B3LYP/6-311++G(d) level. The DFT results elucidate the detailed catalytic cycle, which involves the formation of a covalent reactant–BAIL–(methanol)n (n = 1/3) intermediate and two transition states. Hydrogen bond interactions were found to exist throughout the process of the catalytic cycle, which are of special importance for stabilizing the intermediate and transition states. Thus, a mechanism involving cooperative hydrogen bonding for BAIL-catalyzed biodiesel production was established. The Gibbs free energy profile based on the above mechanism was validated by the subsequent kinetic study. The trend of activation energy from kinetic mathematical models was reasonably consistent with that obtained from the DFT calculations. [ABSTRACT FROM AUTHOR]

In this study, microwave irradiation is employed for the phenolation of acid-insoluble Klason lignin. Microwave irradiation significantly reduces the reaction temperature (180 → 100 °C) and time (6 h → 10 min) without noticeable differences in the chemical structure of the phenolated lignin compared with the products prepared using a conventional heating method. As the reaction temperature increases (100 → 150 °C), lignin decomposition and crosslinking occur simultaneously, as did phenolation. Upon increasing the phenol-to-lignin ratio, the fragmentation of lignin is enhanced, while the crosslinking reaction is inhibited, leading to a decrease in the molecular weight and glass transition temperature of the phenolated lignin. Density functional theory is applied to elucidate the thermal and non-thermal effects of the electromagnetic field on the phenolation of Klason lignin. The solubility of Klason lignin in tetrahydrofuran and methanol is highly enhanced after phenolation, which allows for its adhesive application on glass, polyethylene naphthalate, and polyimide substrates. [ABSTRACT FROM AUTHOR]

The developmental rapidity of nanotechnology poses higher risks of exposure to humans and the environment through manufactured nanomaterials. The multitude of biological interfaces, such as DNA, proteins, membranes, and cell organelles, which come in contact with nanoparticles, is influenced by colloidal and dynamic forces. Consequently, the ensued nano-bio interface depends on dynamic forces, encompasses many cellular absorption mechanisms along with various biocatalytic activities, and biocompatibility that needs to be investigated in detail. Addressing the issue, the study offers a novel green synthesis strategy for antibacterial AgNPs with higher biocompatibility and elucidates the mechanistic in vivo biocompatibility of silver nanoparticles (AgNPs) at the cellular and molecular levels. The analysis ascertained the biosynthesis of G-AgNPs with the size of 25 ± 10 nm and zeta potential of −29.2 ± 3.0 mV exhibiting LC50 of 47.2 μg mL−1 in embryonic zebrafish. It revealed the mechanism as a consequence of abnormal physiological metabolism in oxidative stress and neutral lipid metabolism due to dose-dependent interaction with proteins such as he1a, sod1, PEX protein family, and tp53 involving amino acids such as arginine, glutamine and leucine leading to improper apoptosis. The research gave a detailed insight into the role of diverse AgNPs-protein interactions with a unique combinatorial approach from first-principles density functional theory and in silico analyses, thus paving a new pathway to comprehending their intrinsic properties and usage. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) molecular sieves with highly dispersed active centers have great potential as catalysts for the transformation of bulky biomass derivatives owing to the ease of molecular diffusion and the deactivation resistance by coke deposition. Here, we report a single-step preparation of a 2D Lewis acidic zincosilicate delaminated MWW layer (Zn-DML) and Lewis–Brønsted acidic ZnAl-DML catalysts by a simple hydrothermal treatment of a borosilicate MWW precursor with Zn and/or Al precursor solutions. Both framework Zn and ultra-small Zn clusters are highly dispersed in Zn-DML, while framework Al species prevail over Zn in ZnAl-DML catalysts. Zn-DML catalysts are more delaminated than ZnAl-DML catalysts. Density functional theory calculations show that heteroatom-substituted 2D MWW layers are more stable than their 3D analogues, and Al-containing systems are more stable than Zn. Lewis acidic Zn-DML was selective for fructose, whereas Lewis–Brønsted acidic ZnAl-DML catalysts were selective for 5-hydroxymethylfurfural in the catalytic glucose conversion. [ABSTRACT FROM AUTHOR]

The present report focuses on the solvent effect on furfural production from xylose in biphasic systems with methods including combined experiments, molecular dynamics (MD) simulations and density functional theory (DFT) calculations. Six most effective and commonly used biphasic solvents for furfural production were comparatively analyzed and discussed based on the kinetic study, partition coefficient, degradation behavior of furfural in organic solvents, distribution of solvent molecules around xylose/furfural molecules, hydrogen bonding, moving trajectories of xylose/furfural, and the solvation free energy. During the hydrothermal reaction of xylose to furfural in biphasic systems, it was found that the conversion efficiency of biphasic systems can be ordered as DCM/H2O > 2-MTHF/H2O > 2-butanol/H2O ≈ MIBK/H2O > CPME/H2O > toluene/H2O according to the xylose conversion and furfural yield, which are dominated by the solvation free energy (ΔGsol) of furfural in organic solvents, and also be affected by three other factors, namely, the maximum solubility of furfural in organic solvents, the ΔGsol value of organic solvents in water, and the side reaction of furfural in organic solvents. The degradation rate of furfural in 2-butanol was detected to be the fastest, and molecular dynamics simulation data showed that the hydrogen bonding between furfural and 2-butanol may accelerate the degradation of furfural. DCM has excellent extraction ability for furfural, and the maximum furfural yield in the DCM/H2O system (81.64%) is much higher than that in other systems during the hydrothermal reaction without additional catalysts. [ABSTRACT FROM AUTHOR]

The conversion of lignin into aromatics as commodity chemicals and high-quality fuels is a highly desirable goal for biorefineries. However, the presence of robust inter-unit carbon–carbon (C–C) bonds in natural lignin seriously impedes this process. Herein, for the first time, we report the selective cleavage of C–C bonds in β-O-4 and β-1 linkages catalyzed by cheap copper and a base to yield aromatic acids and phenols in excellent yields in water at 30 °C under air without the need for additional complex ligands. Isotope-labeling experiments show that a base-mediated Cβ–H bond cleavage is the rate-determining step for Cα–Cβ bond cleavage. Density functional theory (DFT) calculations suggest that the oxidation of β-O-4 ketone to a key intermediate, i.e., a peroxide, by copper and O2 lowers the Cα–Cβ bond dissociation energy and facilitates its subsequent cleavage. In addition, the catalytic system could be successfully applied to the depolymerization of various authentic lignin feedstocks, affording excellent yields of aromatic compounds and high selectivity of a single monomer. This study offers the potential to economically produce aromatic chemicals from biomass. [ABSTRACT FROM AUTHOR]

Green synthesis of porous anode materials with high performance and low cost remains a great challenge for the lithium-ion battery industry at present. Herein, we propose a green strategy to synthesize Sn submicron spheres/porous carbon (denoted as Sn/PC) composites by the direct carbonization of disodium stannous citrate, which is composed of Sn submicron spheres supported by porous carbon. Self-generated Na2CO3 during carbonization serves as the template to support the formation of porous carbon. The obtained porous carbon can efficaciously constrain the aggregation of Sn and prevent the volume expansion of Sn submicron spheres. Such particular structural characteristics endow the Sn/PC electrode with high discharge capacity (588 mA h g−1 after 200 cycles at 100 mA g−1) and long cycle life (431.8 mA h g−1 after 2000 cycles at 1200 mA g−1). Meanwhile, the full cell paired with the LiCoO2 cathode affords a high discharge capacity of 511.4 mA h g−1. The in-depth insights into the lithium storage mechanisms of the electrode are investigated by in situ XRD technique. The conductivity performance for the heterointerface of Sn and C is systematically studied by density functional theory calculations. This green strategy can initiate new horizons for fabricating other anode materials with conspicuous volume expansion. [ABSTRACT FROM AUTHOR]

Volatile organochlorine compounds (VOXs) present in biogas can cause many technological and environmental problems. During the combustion of biogas containing VOXs, corrosion, as well as the formation of toxic by-products (polyhalogenated dioxins and furans) and further emission to the atmosphere, may occur. Therefore, in this study, a new procedure based on physical absorption was developed. In order to meet the requirements of green chemistry and green engineering, new deep eutectic solvents (DESs) composed of natural components were used in the absorption studies. Several physical properties of new DESs were determined, along with the absorbent formation mechanisms, by means of spectroscopic analysis and density functional theory. The most important absorption parameters, i.e., the type of DES, gas flow rate,the type of matrix gas, temperature, and initial concentrations of VOXs were optimized. The obtained results indicate that DES composed of syringol and levulinic acid in a 1 : 1 molar ratio could efficiently absorb VOXs. The DES regeneration studies demonstrated that the absorption capacities of DES did not change after ten absorption-desorption cycles. Studies on the absorption mechanisms indicated that H-bonding and van der Waals interactions were the main driving forces for the removal of VOXs from biogas. [ABSTRACT FROM AUTHOR]

Efficient catalytic oxidative C–C bond cleavage with dioxygen is useful and challenging to prepare oxygenated fine chemicals from biomass. Herein, we report a catalytic strategy for the preparation of γ-butyrolactone (GBL) by photocatalytic oxidation of tetrahydrofurfuryl alcohol (THFA), tetrahydrofurfuric acid (THFCA), or other furfural derivatives at room temperature under visible-light irradiation. Metal-free mesoporous graphitic carbon nitride was used as the photocatalyst and O2 was used as the oxidant. The effects of various semiconductor catalysts, light sources with different wavelengths, and the reaction time on the photocatalytic oxidation of THFA to GBL were separately investigated. Furthermore, the reaction mechanism was investigated through serious control experiments and the reaction pathway was investigated through density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

A direct electrooxidative cross-dehydrogenative-coupling (CDC) reaction between N-aryl-tetrahydroisoquinolines and 4-hydroxycoumarins has been realized. This protocol provides a green, mild and fast method to construct 3-tetrahydroisoquinoline substituted coumarins in the absence of any catalysts and exogenous oxidants. A variety of N-aryl-tetrahydroisoquinolines and 4-hydroxycoumarins are compatible with this transformation to give the corresponding products in moderate to excellent yields. Moreover, the results of control experiments, cyclic voltammetry experiments, and density functional theory (DFT) calculations indicated that the electrooxidative CDC reaction might involve both radical addition and nucleophilic addition processes. [ABSTRACT FROM AUTHOR]

Graphdiyne, a new member of the 2D carbon family, has exhibited interesting physiochemical properties attracting academic attention. Its π-conjugated structure with unique sp–sp2 bonding demonstrates a great potential for electrocatalysis. As electrochemical CO2 reduction reaction (CO2RR) has been recognized as a highly promising CO2 utilization technique, the search for active catalysts is critical for the development of CO2RR. Herein, using density functional theory calculations, we studied the activity and selectivity of graphdiyne towards CO2RR. The reaction free energy diagrams are thoroughly investigated, and the results show that the hybridization of sp–sp2 is crucial for high activity owing to the strong adsorption of the *COOH intermediate. Moreover, nitrogen-doping on graphdiyne further improves the activity and selectivity towards CH3OH and CH4 products. The lowest limiting potential of CH3OH on nitrogen-doped graphdiyne is reduced to −0.46 V. The current study predicts the high activity of graphdiyne towards CO2RR, and illustrates the key role of hybridization on the reactivity of the carbon catalysts. [ABSTRACT FROM AUTHOR]

In this study, a series of high-activity imidazole-based dicationic ionic liquids (DILs) were designed and prepared as efficient catalysts for balancing the reactivity between the endo-hydroxyl group (endo-OH) and the exo-hydroxyl group (exo-OH) of isosorbide (ISO) to synthesize high molecular weight poly(isosorbide carbonate) (PIC). Meanwhile, the thermal performance of PIC was precisely optimized by regulating the chain configuration. The results showed that when the trace amounts (4.5 × 10−5 based on the ISO molar amount) of bis-(3-methyl-1-imidazole)-ethylene dibromide ([C2(Min)2][Br]2) were used, the weight average molecular weight (Mw) of PIC reached 98 700 g mol−1. It could be concluded from the results of the experiment and the stimulation that the high catalytic activity of DILs was attributed to the strong electrostatic interaction between the cation and the substrate and the effective balance of the reactivity of the endo-OH and the exo-OH. Furthermore, we found that the reduction of hydroxyl groups in the terminal groups and the increase of endo–endo (a1) structure in the repeating unit improved the thermal properties of PIC. Finally, 1H NMR, Fourier infrared spectroscopy, and density functional theory (DFT) calculations were used to verify the reaction process through anion and cation multi-site synergistic effect and a possible electrophilic–nucleophilic reaction mechanism was successfully obtained. [ABSTRACT FROM AUTHOR]

In order to extract lignin, a novel near-neutral deep eutectic solvent (DES) was developed to treat wheat straw which facilitated its subsequent enzymatic glycation. The DES, whose in situ complexation promotes lignin depolymerization, was composed of choline chloride (ChCl), boric acid (BA), and polyethylene glycol-200 (PEG-200). Our results showed that this kind of DES could dissolve a large amount of lignin and hemicellulose yet retained cellulose well. Under optimum conditions (DES ratio of 1 : 1 : 1.5, 120 °C, 4 h), the proportions of lignin and hemicellulose removed amounted to 88.39% and 84.38%, respectively, with enzymatic digestibility reaching 59.3% in the subsequent enzymatic saccharification with a limited timeframe (5 days) and low enzyme load (30 FPU g−1). The results also demonstrated that lignin's removal rate was positively correlated with the amount of BA used in the DES. The 2D-HSQC NMR, FTIR and TG analyses showed the regenerated lignin to be a typical H–G–S type retaining its intact structure (e.g., β-O-4, β-β, β-5, etc.), whose carbon chain backbone is stable. GPC analysis revealed that this extracted lignin had low molecular weight and a narrower distribution range. Density functional theory showed that BA could bond with –OH similar to Cl−, and it occupied more effective sites than Cl− to break the hydrogen-bonding network between lignin and cellulose. Importantly, the DES can be used multiple times without significantly reducing its efficiency, and its structure and properties remain virtually unchanged throughout the use cycle. [ABSTRACT FROM AUTHOR]

Gas–water interface mediated photoconversion of renewable biomass into fuels is a promising strategy to mitigate the impending environmental pollution and energy crisis. Herein, a gas–water interface is engineered to photoconvert fatty acids (FAs, C6–C9) into gaseous Cn-2 linear alpha-olefins (LAOs) with a high selectivity (87–91%) under mild conditions; especially, experiments with different interfaces demonstrate that the gas–water interface plays a crucial role in the enhanced selective production. The thinner molecular layer and ordered packing significantly promote the production of LAOs by maximizing the hydrogen bonding between FAs and interfacial water molecules. Furthermore, density functional theory (DFT) calculations, at the molecular level, elaborate that interfacial water could activate the reactions through hydrogen bonding lowering the reaction barrier of initial photoreaction of FAs. Additionally, different atmospheres are found to impact the pathways and products of photoconversion, thus enabling the controllable synthesis of LAOs. Unlike the metal/enzyme-involved harsh catalytic system, the gas–water interface serves as a green, low-cost and efficient 'venue' which can be infinitely reused for hydrocarbon production, pioneering a new way for mitigating the energy crisis and developing a truly green and sustainable society. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of carbon dioxide (CO2) into multi-carbon fuels and chemical feedstocks is important but remains challenging. Here, we report the stabilization of Cu+ within a CuO–CeO2 interface for efficient and selective electrocatalytic CO2 reduction to ethylene under ambient conditions. Tuning the CuO/CeO2 interfacial interaction permits dramatic suppression of proton reduction and enhancement of CO2 reduction, with an ethylene faradaic efficiency (FE) as high as 50.0% at −1.1 V (vs. the reversible hydrogen electrode) in 0.1 M KHCO3, in stark contrast to 22.6% over pure CuO immobilized on carbon black (CB). The composite catalyst presents a 2.6-fold improvement in ethylene current compared to that of CuO/CB at similar overpotentials, which also exceeds many recently reported Cu-based materials. The FE of C2H4 remained at over 48.0% even after 9 h of continuous polarization. The Cu+ species are believed to be the adsorption as well as active sites for the activation of CO2 molecules, which remain almost unchanged after 1 h of electrolysis. Further density functional theory calculations demonstrate the preferred formation of Cu+ at the CuO–CeO2 interface. This work provides a simple avenue to convert CO2 into high-value hydrocarbons by rational stabilization of Cu+ species. [ABSTRACT FROM AUTHOR]

The development of high-efficiency noble-metal-free catalysts for the electrochemical nitrogen reduction reaction (NRR) to ammonia under ambient conditions has great significance in fertilizer production and energy storage. Considering the major role of Mo-nitrogenase with the FeMo cofactor in the biological N2 fixation process, the design and preparation of Mo and Fe bi-active metal based hybrid materials for the NRR under ambient conditions is proposed in this work. By using PMo12@MOF-100(Fe)@PVP (polyvinylpyrrolidone) as the precursor, two cost efficient FeMo-based electrocatalysts Fe1.89Mo4.11O7/FeS2@C and FeMoO4/FeS2@C were designed and fabricated for the NRR under room temperature and pressure conditions (RTP) via the easy-to-implement hydrothermal sulfuration method. The experiment results confirm that Fe1.89Mo4.11O7/FeS2@C (NH3 yield rate of 105.3 μg h−1 mgcat.−1, FE of 54.7% at −0.4 V vs. RHE) is more efficient towards the NRR than FeMoO4/FeS2@C (NH3 yield of 51.0 μg h−1 mgcat.−1, FE of 43.9% at −0.5 V vs. RHE) in acidic electrolytes; moreover they are all superior to most of the electrocatalysts reported to date. Further electrocatalysis of Fe1.89Mo4.11O7/FeS2@C in alkaline electrolytes (NH3 yield of 86.3 μg h−1 mgcat.−1, FE of 53.6% at −0.4 V vs. RHE) reveals the extensive NRR catalytic activity of this hybrid material. Density functional theory (DFT) calculation indicates that the NRR on Fe1.89Mo4.11O7/FeS2 has optimized nitrogen binding which facilitates the fast kinetics process through an enzymatic mechanism, and the protonation of N2 to form *N2H species is the potential-determining step (PDS) with the maximum ΔG values (+0.61 eV). This work opens up a significant opportunity to develop a family of efficient and robust FeMo-based electrocatalysts for the NRR under ambient conditions by using polyoxometalate-based metal–organic frameworks (POMOFs) as precursors by tuning metal sources. [ABSTRACT FROM AUTHOR]

CO2, the main component of greenhouse gas, is currently developed as a promising surrogate of carbon feedstock. Among various conversion routes, CO2 undergoing catalytic reduction can furnish hydrogen/energy carriers and value-added chemicals, while specific metal-containing catalysts or organocatalysts are often prerequisite for smooth proceeding of the involved reaction processes. In this work, both formic acid and N-containing benzoheterocyclic compounds (including various benzimidazoles, benzothiazole, and benzoxazole) along with silanols could be synthesized with high yields (>90%) from catalyst-free reductive upgrading of CO2 under mild conditions (50 °C). The endogenous X–C＝O species, derived from the N-methyl-substituted amide-based solvent [Me2N–C(＝O)–R], especially PolarClean, and O-formyl group [O–C(＝O)–H] of in situ formed silyl formate, were found to play a prominent promotional role in the activation of the used hydrosilane for reductive CO2 insertion, as demonstrated by density functional theory (DFT) calculations and isotopic labeling experiments. Moreover, reaction mechanisms and condition-based sensitivity assessment were also delineated. [ABSTRACT FROM AUTHOR]

Taking into account that the transformation of biomass-derived 2,5-dimethylfuran (DMF) to p-xylene involves Diels–Alder (DA) cycloaddition as the limiting step, the use of an ITQ-2 zeolite obtained by direct synthesis (DS-ITQ-2) as a catalyst for this reaction is proposed based on the fact that the organic molecule employed for its synthesis mimics the size and shape of the DA oxanorbornene cycloadduct intermediate. Periodic Density Functional Theory (DFT) calculations reveal a better stabilization of the oxanorbornene intermediate within the external hemicavities or "cups" of the DS-ITQ-2 zeolite (MWW-framework) than in other zeolites employed for this reaction, such as FAU and Beta. Interestingly, experimental results also show improved catalytic conversion values for the DS-ITQ-2 zeolite compared to FAU and Beta, in good agreement with the stabilization energies calculated by DFT. The "ab initio" catalyst design presented here to enhance the catalytic performance for the transformation of biomass-derived products is a valuable example that could be employed for the rationalization of other chemical processes catalyzed by zeolites. [ABSTRACT FROM AUTHOR]

Glycolysis of poly(ethylene terephthalate) (PET) is a prospective way for degradation of PET to its monomer bis(hydroxyethyl) terephthalate (BHET) which can be polymerized again to form new qualified PET materials, and hence provides possibilities for a permanent loop recycling. However, most of the reported glycolysis catalysts are metal-based, leading to high cost and negative environmental impact. In this study, we developed a series of choline-based ionic liquids (ILs) without metals and applied them in the glycolysis of PET as catalysts. Choline acetate ([Ch][OAc]), which is cheaper, more biologically compatible and environmentally friendly in comparison with conventional imidazolium metal-based ILs, can achieve a comparable or even better performance than them. Under optimum conditions (PET (5.0 g), ethylene glycol (EG) (20.0 g), [Ch][OAc] (5 wt%), 180 °C, 4 h, atmospheric pressure), the yield of BHET reached up to 85.2%. Additionally, the reaction kinetics was studied and proved to be the shrinking-core model. The apparent activation energy is 131.31 kJ mol−1, and the pre-exponential factor is 1.21 × 1013 min−1. Finally, based on the experimental results and density functional theory (DFT) calculations, a possible mechanism was proposed. The promotion of the glycolysis reaction is attributed to the activation of EG by the formation of hydrogen bonds between EG and the IL. [ABSTRACT FROM AUTHOR]