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Abstract Extrusion-based three-dimensional (3D) printing of gelatin (Gel) is crucial for fabricating bone tissue engineering scaffolds via additive manufacturing. However, the thermal instability of Gel remains a persistent challenge, as it tends to collapse at mild temperatures. Current approaches often involve simply mixing Gel particles with various materials, resulting in biomaterial inks that lack uniformity and have inconsistent degradation characteristics. In this study, acetic acid was used to dissolve Gel and polycaprolactone (PCL) separately, producing homogeneous Gel/PCL dispersions with optimal pre-treatment performance. These dispersions were then combined and hybridized with nano-hydroxyapatite (n-HA) to create a composite printing ink. By evaluating the printability of the ink, the optimal conditions were identified: a n-HA concentration of 50% (w/w), a printing temperature of 10–15 ℃, a printing pressure of 2.5 bar, and a printing speed of 7 mm/s. The resulting biomaterial inks, with a composition of 25% Gel, 25% PCL, and 50% n-HA, demonstrated excellent printability and stability, along with significantly enhanced mechanical properties. As a result, 3D scaffolds with high printability and shape fidelity can be printed at room temperature, followed by deep freezing at -80 ℃ and cross-linking with vanillin. The Gel-based composite scaffolds demonstrated excellent biocompatibility, cell adhesion, cell viability and nano-hydroxyapatite absorption in vitro. Additionally, in vivo experiments revealed that the bioactive scaffold biodegraded during implantation and significantly promoted bone regeneration at the defect site. This provides a promising strategy for treating bone defects in clinical setting. In conclusion, the Gel/PCL/n-HA biomaterial inks presented here offer an innovative solution for extrusion bioprinting in the field of bone tissue engineering. Graphical Abstract

Electrochromism is the process by which a material applies a small electrical signal to change the optical properties (transmittance, reflectance, absorptivity and emissivity) of the material reversibly or permanently through REDOX reactions resulting from ion and electron embedding/ejection. Metal-organic framework (MOF) are advantageous materials for electrochromic application due to their high porosity, large specific surface area and orderly pore structure, that promotes the adsorption of electrolyte ions, ion diffusion and charge transfer. In addition, MOFs possess a variety of ligands and metal centers, allowing for design of composition types and pore structure sizes. This grants them the advantages of both organic electrochromic materials, such as vivid colors and fast color transformation, and inorganic electrochromic materials, like high coloring efficiency and excellent stability. This paper reviews the current research progress of MOF electrochromic materials, including materials design, electrochromic properties, and application.

Recently, lithium-ion batteries (LIBs), due to their superior performance, have been vastly applied in electronic, auto, and other industries, resulting in the generation of an increasing amount of spent LIBs. What's worse, LIBs contained potentially toxic substances, including heavy metals, toxic and flammable electrolyte containing LiBF4, LiClO4, and LiPF6. Conventional disposal of spent LIBs via landfill or incineration exerts tremendous pressure on the environment. It was necessary to adopt efficient, low-cost, and environmentally friendly approaches to valorizing spent LIBs, which could not only alleviate the shortage of rare resources by recycling valuable elements such as Cu, Li, Mn, Ni, Co, and Al, but also eliminate the pollution of harmful components in batteries and realize the recycling and sustainable industry related to consumer electronics and electric vehicles (EVs). Given this, this paper summarized the recycling technologies of spent LIBs, including pyrometallurgy (melting reduction and roasting methods) and hydrometallurgy (leaching, precipitation, extraction, ion-exchange, electrochemical, sol-gel methods), and electrolyte recycling (organic solvent extraction and supercritical extraction methods). Pyrometallurgy technologies had relatively decent metal recovery rates but were associated with high energy consumption and atmospheric emission issues. Hydrometallurgical technologies were more environmentally friendly and efficient in recovering spent LIBs, although disposing of the wastewater generated from the process remained a challenge. In addition, the different industrial processes and various countries’ related policies of recycling spent LIBs were investigated. In the end, the outlooks and future directions of recycling spent LIBs were proposed.

Novel substrates consisted of different fresh agro-industrial residues, their corresponding and commercial spent mushroom substrates (i.e. SMS deriving from laboratory-scale experiments and SMS deriving from industrial-scale experiments by Green Zin S.A. - SMS GZ) and Pleurotus waste (PW; stipes/mishappen mushrooms) were used in blends for a new cultivation cycle of Pleurotus ostreatus and P. eryngii mushrooms in bags. Their impact on the biochemical properties (intra-cellular polysaccharides - IPSs, protein, lipid, total phenolic compounds - TPCs, individual carbohydrates composition of the IPSs) in the first- and second-flush whole mushrooms, pilei and stipes, as well as the fatty acids composition, the antioxidant activity (in the first-flush mushroom parts) and glucan content of stipes were examined. Both species produced satisfactory IPSs quantities in all substrates (28.69–46.38 %, w/w) and significant protein amounts (18.37–26.80 %, w/w). The further SMS addition (80 %, w/w instead of 40 %, w/w) in the cultivation substrates affected positively the mushroom IPSs values, whereas the highest protein content was detected in mushroom's parts cultivated on substrates consisted of fresh agro-industrial residues. Mushroom's lipid content was affected differently by the various substrate combinations, with SMS presence resulting in mushrooms with a lower fat content than those produced in substrates with PW addition. Fresh substrates with PW and those with coffee residue were the most favorable for TPCs production. Regarding production flushes, the nutritional value of mushrooms was comparable between them, only a slight increase in TPCs of second-flush carposomes was detected. Glucose was the predominant monosaccharide of the produced IPSs, combined with a significant production of total and β- glucans. SMSs and PW addition had a positive impact on antioxidant activity, too. A higher quantity of lipids, TPCs and significant antioxidant activity were detected in all Pleurotus pilei than stipes, whereas the latter were richer in IPSs. Both pilei and stipes had a significant protein amount. Hence, the data obtained by this study support the positive effect of different types of SMS and mushroom waste on P. ostreatus and P. eryngii nutritional value.

Paper-based materials made from cellulose have been sought after as a sustainable and inexpensive packaging option. However, the porous structure and high hydrophilicity of paper-based materials result in inadequate water and oil repellency, as well as a limited water vapor barrier. In this work, lignin nanoparticles (LNPs) were prepared using a high-speed homogenizer, and subsequently coated on base paper along with cationic starch to enhance its multi-barrier performance to facilitate the packaging application. The LNPs obtained through such a facile process formed stable colloidal dispersion in water, which exhibited excellent interfacial compatibility with cationic starch. During the coating process, a highly adhesive emulsion consisting of cationic starch and LNPs were coated on the surface of base paper, imparting good hydrophobic properties to the paper. The resulting paper material exhibited good water resistance (Cobb value of 37.5 g m−2), high oil resistance (Kit rating 9) and tensile strength (48.93 MPa). The reduction in water vapor transmission rate (WVTR) exceeds sixfold. This study provides a new avenue for the application of lignin in high-barrier, fluorine-free, water-and oil-resistant packaging materials.

Since the properties of polyaniline (PANI) are widely related to the type of its dopant, the present manuscript has an objective to define whether and to what extent the protic ionic liquids contribute to doping PANI. Hence, pyrrolidinium p-toluenesulfonate [Pyrr][PTS] – a protic ionic liquid – has been investigated either as a polymerisation medium or as a secondary dopant. As for the polymerisation medium, it was found that binary mixtures of [Pyrr][PTS]/water, with different weight ratios, are convenient to prepare PANI in emeraldine salt form. Furthermore, the structural analysis of the resulted PANI has revealed that the cation of [Pyrr][PTS] does not functionalise PANI backbone and [Pyrr][PTS] acts like the typical Brřnsted acid in doping PANI, regardless of the amount of [Pyrr][PTS] in the polymerisation medium. To confirm this conclusion, [Pyrr][PTS] has also been studied as a secondary dopant: the conventional PANI has been prepared, deprotonated then dispersed into [Pyrr][PTS]/water with different formulations. The results have shown that [Pyrr][PTS] leads to the formation of reprotonated PANI without altering structural change. One can thus conclude that the noncovalent functionalisation of PANI with the cation of the protic ionic liquids is not an exigent requirement to prepare the emeraldine salt form of PANI in aqueous solutions of protic ionic liquids.

Polydimethylsiloxane has the characteristics of low-temperature flexibility and excellent aging resistance. However, high molecule mobility and weak interactions between PDMS molecules result in poor mechanical strength and deficient gas barrier properties of PDMS composites. Herein, diamino-polydimethylsiloxane (PDMS) was reacted with 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BDO) to form urea-carbamate functionalized PDMS (MDI-PDMS-BDO) with different hard segment contents. Furthermore, the modified graphene oxide (iGO) was obtained by the reaction between graphene oxide (GO) and MDI. iGO was further introduced into the functionalized PDMS to prepare iGO/urethane-urea functionalized PDMS composites (iGO/MDI-PDMS-BDO). An ordered structure was formed by the hard segments of the MDI-PDMS-BDO functionalized PDMS. A strong urea-based interface was also obtained between iGO and functionalized PDMS. iGO became the cross-linking center in the iGO/MDI-PDMS-BDO composites. Due to the ordered structure of hard segments and the iGO network formed in the PDMS composite with only 0.07 wt% iGO, the tensile strength and gas barrier properties of the iGO/MDI-PDMS-BDO composite were increased by 18 times and 64.27%, respectively, compared with pure PDMS.

Thermoplastic (TP) composites, known for their ease of handling, suitability for high production rates, and recyclability, are emerging as a promising alternative to thermoset-based composites. The expected growth in TP-based composites in automotive, sports, and aerospace industries may result in increased post industrial waste. To address this, we repurposed our in-house process scrapped carbon fibre-reinforced polycarbonate tapes into sheet moulding compounds (SMCs) and Hybridised SMCs (Hy-SMCs) using compression moulding. In Hy-SMCs, the top and bottom layers were unidirectional tapes, while the core section had randomly oriented platelets in a 50:50 ratio. Our evaluation included qualitative and thermo-mechanical standard tests. The incorporation of unidirectional tapes in Hy-SMCs significantly improved the tensile and flexural properties of SMCs. Specifically, these enhancements resulted in an impressive 81 to 85% increase in mechanical strength compared to the standard aluminium grade. Additionally, Hy-SMCs exhibited a 120 to 130% increase in tensile and flexural properties compared to SMCs. Fractography revealed a complex relation between fractured surfaces, with multimode failures in both SMCs and Hy-SMCs. Also, the non-destructive evaluation showed platelet reorientation during consolidation and localised voids with increased specimen thickness.

In this study, a novel methodology for the fabrication of gradient porous structures is introduced, predicated upon the phase evolution characteristics of immiscible polymer blends. Initially, a comprehensive flow-phase field dynamics model is developed. This model couples the principles of phase field theory and the dynamics of fluid flow to the two-phase evolution process, facilitating a numerical simulation of the phase evolution. Subsequently, the phase field parameters of model are determined and combined with the temperature field, thereby enabling a targeted and controlled fabrication of gradient porous structures. Finally, the efficacy and practical applicability of the proposed methodology are substantiated through the construction of illustrative examples. This approach, as delineated herein, provides a robust framework for the efficient design and realization of intricate, interconnected gradient porous structures with potential applications in various scientific and engineering domains.

Electron beam (EB) treatment of a high vinyl styrene-butadiene-styrene (SBS) block copolymer was accomplished by exposing the polymer to high-energy electrons generated from an electron accelerator. This resulted in the formation of free radicals of carbon on the polybutadiene units in the backbone of the elastomer and subsequent radical coupling to produce cross-links. In the process, some unavoidable chain scission (CS) also occurred. An attempt was made to mathematically trace the nature of the CS as a function of radiation dose with the aid of the experimentally determined cross-link density (CLD), tensile strength and tear strength, the latter three also obtained as functions of radiation dose. The radiation dose was varied from 12.5 to 300.0 kGy in multiples of 12.5 kGy. The novelty of the work was, in part to create a function that can be used to calculate chain-scission in dependence of EB radiation dose. It was found that a change in the ratio of CS to CLD occurred as a function of radiation dose over the previously calculated constant ratio, using the Charlesby-Pinner equation.

This study compares the efficiency of commercially available sorbitol-based clarifying agent (NA) and varying amounts of long chain-branched polypropylene (LCBPP) acting as a specific α-nucleating agent for linear polypropylene (PP). The sorbitol-based clarifying agent, 1,3;2,4-bis(3,4-dimethyl benzylidene)sorbitol (Millad 3988), in concentration 0.2 wt%, and LCBPP in the concentration of 1, 2, 5 and 10 wt% were mixed into PP. The comparison of the effect of NA and long branches under isothermal conditions on the crystallization process, crystallinity and polymorphic composition was realized by differential scanning calorimetry and wide-angle X-ray scattering. The addition of long chain-branched polypropylene, even at the lowest concentration, performs better at higher crystallization temperatures and has a superior effect on the crystallization process, crystallization rate and overall crystallization than the addition of NA.

Analyzing rubber waste is crucial for value-added recycling, but the multitude of ingredients in vulcanized networks makes it challenging to characterize cross-linked rubbers. A combination of analytical techniques is usually required. In this study, two complementary characterization techniques, based on Fourier transform infrared (FTIR) spectroscopy and derivative thermogravimetric analysis (DTGA) were applied to analyze the structural, physical, and thermal behavior of ground tire rubber (GTR) samples devulcanized by two different processes. A set of samples was devulcanized by only microwaves (MW) while another set was treated with a combination of a thermochemomechanical (TM) process, which included the use of a devulcanization aid such as benzoyl peroxide, and microwaves. The combined technique proved to be more efficient in terms of the degree of devulcanization, significantly reducing the cross-linking density. However, the combined thermochemomechanical and microwave (TM/MW) devulcanization process resulted in greater degradation of the main rubber chains in the cross-linked network compared to the process using only microwaves.

The thermal response of gold and platinum spherical nanoparticles (NPs) upon cooling is studied through atomistic molecular dynamics simulations. The goal is to identify the morphological transformations occurring in the nanomaterials as well as to quantify their dependence on temperature, chemistry, and NP size. For diameters smaller than 3 nm, the transition temperature from a melted/amorphous to a highly crystalline state varies considerably with NP size. For larger NPs, the transition temperature is almost diameter-independent, yet it differs considerably from the transition temperature of the respective bulk materials. The platinum NPs possess a higher level of crystallinity than the gold counterparts under the same conditions because of the stronger cohesive forces that drive the crystallization process. This observation is also supported by the simulated X-ray powder diffraction patterns of the nanomaterials. The larger NPs have a multifaceted crystal surface, and their shape remains almost constant regardless of temperature variations. The smaller NPs have a smoother and more spherical surface, and their shape varies greatly with temperature. By studying the variation of nano-descriptors commonly employed in QSAR models, a qualitative picture of the NPs’ toxicity and reactivity emerges: Small/hot NPs are likely more toxic than their large/cold counterparts. Because of the small size of the NPs considered, the observed structural modifications are challenging to be studied by experimental techniques. The present approach can be readily employed to study other metallic and metal oxide nanomaterials.

The interfaces between medical implants and living tissues are of great complexity because of the simultaneous occurrence of a wide variety of phenomena. The engineering of implant surfaces represents a crucial challenge in material science, but the further improvement of implant properties remains a critical task. It can be achieved through several processes. Among them, the production of specialized coatings based on carbon-based materials stands very promising. The use of carbon coatings allows one to simultaneously fine-tune tribological, mechanical, and chemical properties. Here, we review applications of nanostructured carbon coatings (nanodiamonds, carbon nanotubes, and graphene-related materials) for the improvement of the overall properties of medical implants. We are focusing on biological interactions, improved corrosion resistance, and overall mechanical properties, trying to provide a complete overview within the field.

Sensors are applied to many fields nowadays because of their high sensitivity, low cost, time-saving, user-friendly, and excellent selectivity. Current biomedical and pharmaceutical science has one focus on developing nanoparticle-based sensors, especially biopolymeric nanoparticles. Alginate is a widely used biopolymer in a variety of applications. The hydrogel-forming characteristic, the chemical structure with hydroxy and carboxylate moieties, biocompatibility, biodegradability, and water solubility of alginate have expanded opportunities in material and biomedical sciences. Recently, research on alginate-based nanoparticles and their applications has begun. These materials are gaining popularity because of their wide usage potential in the biomedical and pharmaceutical fields. Many review papers describe applications of alginate in the drug delivery field. The current study covers the structural and physicochemical properties of alginate-based nanoparticles. The prospective applications of alginate-based nanomaterials in various domains are discussed, including drug delivery and environmental sensing applications for humidity, heavy metals, and hydrogen peroxide. Moreover, biomedical sensing applications of alginate-based nanoparticles regarding various analytes such as glucose, cancer cells, pharmaceutical drugs, and human motion will also be reviewed in this paper. Future research scopes highlight existing challenges and solutions.

Direct electron beam writing is a powerful tool for fabricating complex nanostructures in a single step. The electron beam locally cleaves the molecules of an adsorbed gaseous precursor to form a deposit, similar to 3D printing but without the need for a resist or development step. Here, we employ for the first time a silver β-diketonate precursor for focused electron beam-induced deposition (FEBID). The used compound (hfac)AgPMe3 operates at an evaporation temperature of 70–80 °C and is compatible with commercially available gas injection systems used in any standard scanning electron microscope. Growth of smooth 3D geometries could be demonstrated for tightly focused electron beams, albeit with low silver content in the deposit volume. The electron beam-induced deposition proved sensitive to the irradiation conditions, leading to varying compositions of the deposit and internal inhomogeneities such as the formation of a layered structure consisting of a pure silver layer at the interface to the substrate covered by a deposit layer with low silver content. Imaging after the deposition process revealed morphological changes such as the growth of silver particles on the surface. While these effects complicate the application for 3D printing, the unique deposit structure with a thin, compact silver film beneath the deposit body is interesting from a fundamental point of view and may offer additional opportunities for applications.

The present study investigates the effects of input wavelength (1064, 532, and 355 nm) and surrounding liquid environment (distilled water and aqueous NaCl solution) on the picosecond laser ablation on silver (Ag), gold (Au), and Ag/Au alloy targets. The efficacy of the laser ablation technique was meticulously evaluated by analyzing the ablation rates, surface plasmon resonance peak positions, and particle size distributions of the obtained colloids. The nanoparticles (NPs) were characterized using the techniques of UV–visible absorption, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Furthermore, NPs of various sizes ranging from 6 to 35 nm were loaded onto a filter paper by a simple and effective drop-casting approach to achieve flexible surface-enhanced Raman spectroscopy (SERS) substrates/sensors. These substrates were tested using a simple, portable Raman device to identify various hazardous chemicals (malachite green, methyl salicylate, and thiram). The stability of the substrates was also systematically investigated by determining the decay percentages in the SERS signals over 60 days. The optimized SERS substrate was subsequently employed to detect chemical warfare agent (CWA) simulants such as methyl salicylate (a CWA simulant for sulfur mustard) and dimethyl methyl phosphonate (has some structural similarities to the G-series nerve agents) at different laser excitations (325, 532, and 633 nm). A notably higher SERS efficiency for CWA simulants was observed at a 325 nm Raman excitation. Our findings reveal that a higher ablation yield was observed at IR irradiation than those obtained at the other wavelengths. A size decrease of the NPs was noticed by changing the liquid environment to an electrolyte. These findings have significant implications for developing more efficient and stable SERS substrates for chemical detection applications.

Over recent decades, nanomedicine has played an important role in the enhancement of therapeutic outcomes compared to those of conventional therapy. At the same time, nanoparticle drug delivery systems offer a significant reduction in side effects of treatments by lowering the off-target biodistribution of the active pharmaceutical ingredients. Cancer nanomedicine represents the most extensively studied nanotechnology application in the field of pharmaceutics and pharmacology since the first nanodrug for cancer treatment, liposomal doxorubicin (Doxil®), has been approved by the FDA. The advancement of cancer nanomedicine and its enormous technological success also included various other target diseases, including hepatic fibrosis. This confirms the versatility of nanomedicine for improving therapeutic activity. In this review, we summarize recent updates of nanomedicine platforms for improving therapeutic efficacy regarding liver fibrosis. We first emphasize the challenges of conventional drugs for penetrating the biological barriers of the liver. After that, we highlight design principles of nanocarriers for achieving improved drug delivery of antifibrosis drugs through passive and active targeting strategies.

Over the last few decades, field-effect transistor (FET)-based biosensors have demonstrated great potential across various industries, including medical, food, agriculture, environmental, and military sectors. These biosensors leverage the electrical properties of transistors to detect a wide range of biomolecules, such as proteins, DNA, and antibodies. This article presents a comprehensive review of advancements in the architectures of FET-based biosensors aiming to enhance device performance in terms of sensitivity, detection time, and selectivity. The review encompasses an overview of emerging FET-based biosensors and useful guidelines to reach the best device dimensions, favorable design, and realization of FET-based biosensors. Consequently, it furnishes researchers with a detailed perspective on design considerations and applications for future generations of FET-based biosensors. Finally, this article proposes intriguing avenues for further research on the topology of FET-based biosensors.

Laser interferometry is a well-established and widely used technique for precise displacement measurements. In a non-contact atomic force microscope (NC-AFM), it facilitates the force measurement by recording the periodic displacement of an oscillating microcantilever. To understand signal generation in a NC-AFM-based Michelson-type interferometer, we evaluate the non-linear response of the interferometer to the harmonic displacement of the cantilever in the time domain. As the interferometer signal is limited in amplitude because of the spatial periodicity of the interferometer light field, an increasing cantilever oscillation amplitude creates an output signal with an increasingly complex temporal structure. By the fit of a model to the measured time-domain signal, all parameters governing the interferometric displacement signal can precisely be determined. It is demonstrated, that such an analysis specifically allows for the calibration of the cantilever oscillation amplitude with 2% accuracy.

In this perspective article, Professor Dan Sameoto outlines his opinion on future opportunities in the field of biomimetic adhesives. Despite over twenty years of excellent academic work by groups all around the world in this subfield, the economic value and impact of these materials is somewhat underwhelming. The question for the field is whether it should have a scientific and engineering focus to create every greater performance and understanding of the materials and hope that “if we build it, they will come”. Perhaps we should expand our concept on what could be the desirable end applications for such materials and focus efforts on finding better end applications in which these materials can truly shine; a few of those applications like microfluidics and composites are highlighted in this article. It is time for a next generation of research to look beyond biomimicry and look towards re-engineering applications to make use of these materials’ unique properties in economically viable ways.

Electronic and structural properties of calcium clusters with a varying size range of 2–20 atoms are studied using a two-step scheme within the GW and density functional theory (DFT) with generalized gradient approximation (GGA). The GGA overestimates the binding energies, optimized geometries, electron affinities, and ionization potentials reported in the benchmark. The ground-state structure geometry and binding energy were obtained from the DFT for the ground-state structure of each cluster. The binding energy of the neutral clusters of the calcium series follows an increasing trend, except for a few stable even and odd clusters. The electronic properties of the calcium cluster were studied with an all-electron FHI-aims code. In the G0W0 calculation, the magic cluster Ca10 has relatively high ionization potential and low electron affinity. The obtained ionization potentials from the G0W0@PBE calculation showed that the larger cluster has less variation, whereas the electron affinities of the series have an increasing trend. The ionization potentials from the G0W0 benchmark for the calcium cluster series have not yet been described in the literature.

In this article we discuss how nanoparticles (NPs) of different compositions may interact with and be internalized by cells, and the consequences of that for cellular functions. A large number of NPs are made with the intention to improve cancer treatment, the goal being to increase the fraction of injected drug delivered to the tumor and thereby improve the therapeutic effect and decrease side effects. Thus, we discuss how NPs are delivered to tumors and some challenges related to investigations of biodistribution, pharmacokinetics, and excretion. Finally, we discuss requirements for bringing NPs into clinical use and aspects when it comes to usage of complex and slowly degraded or nondegradable NPs.

A new 3D micro-nano integrated M-shaped carbon nanotube (CNT) architecture was designed and fabricated. It is based on vertically aligned carbon nanotube arrays composed of low-density, mainly double-walled CNTs with simple lateral external contacts to the surroundings. Standard optical lithography techniques were used to locally tailor the width of the vertical block structure. The complete sensor system, based on a broadband blackbody absorber region and a high-resistance thermistor region, can be fabricated in a single chemical vapor deposition process step. The thermistor resistance is mainly determined by the high junction resistances of the adjacent aligned CNTs. This configuration also provides low lateral thermal conductivity and a high temperature coefficient of resistance (TCR). These properties are advantageous for new bolometric sensors with high voltage responsivity and broadband absorption from the infrared (IR) to the terahertz spectrum. Preliminary performance evaluations have shown current and voltage responsivities of 2 mA/W and 30 V/W, respectively, in response to IR (980 nm) absorption for a 20 × 20 μm2 device. The device exhibits an exceptionally fast response time of ≈0.15 ms, coupled with a TCR of −0.91 %/K. These attributes underscore its high operating speed and responsivity, respectively. In particular, the device maintains excellent thermal stability and reliable operation at elevated temperatures in excess of 200 °C, extending its potential utility in challenging environmental conditions. This design allows for further device miniaturization using optical lithography techniques. Its unique properties for mass production through large-scale integration techniques make it important for real-time broadband imaging systems.

Graphene nanoribbons show exciting electronic properties related to the exotic nature of the charge carriers and to local confinement as well as atomic-scale structural details. The local work function provides evidence for such structural, electronic, and chemical variations at surfaces. Kelvin prove force microscopy can be used to measure the local contact potential difference (LCPD) between a probe tip and a surface, related to the work function. Here we use this technique to map the LCPD of graphene nanoribbons grown on a Au(111) substrate. The LCPD data shows charge transfer between the graphene nanoribbons and the gold substrate. Our results are corroborated with density functional theory calculations, which verify that the maps reflect the doping of the nanoribbons. Our results help to understand the relation between atomic structure and electronic properties both in high-resolution images and in the distance dependence of the LCPD.

This article explores the dynamics of nanofluids consisting of copper (TiO2) nanoparticles suspended in water, as they interact with sensor surfaces between two parallel squeezing plates with porous characteristics. This research specifically targets applications involving enhanced heat transfer and magnetohydrodynamic (MHD) control in nanofluid systems. The primary aim is to analyze the effects of nanoparticle aggregation and non-aggregation on sensor surfaces, considering MHD formations and heat transfer in the energy and momentum equations. The research adopts a steady-state fluid condition and utilizes similarity transformations to convert partial differential equations into more manageable ordinary differential equations. The methodology involves shooting methods for solving these nonlinear ordinary differential equations and employs graphical analyses to study the impacts of various parameters such as permeability, magnetic influence, squeeze flow, and radiation on the temperature and velocity profiles of the nanofluid. The results reveal significant dependencies of temperature and velocity profiles on the studied parameters, illustrating varied behaviors in scenarios of both aggregation and non-aggregation of nanoparticles. The findings emphasize how each parameter distinctively influences the heat and flow characteristics of the nanofluid, offering insights into optimizing conditions for better performance and control in practical applications. Future research could focus on extending the model to include transient fluid states and exploring the effects of other nanoparticle materials and shapes. There is also potential to investigate the interactions under different environmental conditions and to incorporate more complex boundary conditions to simulate real-world applications more accurately. Further experimental validation of the theoretical predictions would be beneficial to enhance the reliability and applicability of the findings.

Heat, ultrasonic, microwave, and external energy are the essential conditions in the conventional preparation of nano-cupric oxide (CuO) from copper hydroxide (Cu(OH)2) precursor. In this work, CuSO4 aqueous solution (0.02 mol) was gradually added dropwise into the methanol/sodium hydroxide (NaOH/CH3OH) solution (0.04 mol) in 20 min at normal temperature and then constantly stirred the black solution for about 5 min; nano-CuO was synthesized. The as-prepared CuO had a high purity and a regular nanosize of 4–10 nm. What is more, the by-product sodium sulfate (Na2SO4) could be separated using a high-speed centrifuge, indicating that the methanol could be conveniently recycled; thereby, an environmentally friendly sustainable route of the preparation of nano-CuO was developed. In addition, the as-prepared nano-CuO was melt-compounded with polyamide 6 to produce fiber composites. The results showed that the nano-CuO was uniformly dispersed in PA6 fiber composites and presented an excellent antibacterial performance. Most importantly, the function of methanol in the dehydration process was revealed.

The extraction of uranium from nuclear wastewater through photocatalysis represents a highly viable, environmentally friendly, and sustainable approach, contributing significantly to mitigating environmental degradation while facilitating the efficient recovery of uranium resources. Nonetheless, the development of highly efficient photocatalysts with rapid charge carrier migration and surface reaction kinetics for the effective removal of U(Ⅵ) from uranium-containing wastewater remains a formidable challenge. This study successfully employed template-free self-assembly techniques to fabricate hollow tubular g-C3N4(TCN) and synthesized a tubular donor-acceptor(D-A) organic semiconductor photocatalyst, B-TCNx, by incorporating hydroquinone into the framework of TCN. This innovative photocatalyst was utilized for the photocatalytic removal of U(Ⅵ) under ambient air conditions. The construction of an intra-molecular D-A system enables the separate accumulation of electrons and holes in the acceptor and donor moieties, thereby significantly reducing electron-hole recombination. Furthermore, the spatial separation of electrons and holes in the acceptor and donor moieties leads to the formation of an intrinsic electric field, which facilitates the migration of charge carriers. The research findings indicate that B-TCN60 achieved a remarkable removal rate of 96.8% for U(Ⅵ) within 120 minutes, with a kinetic constant(0.03114 min−1) that is 2.58 times higher than that of TCN(0.01215 min−1). Moreover, negligible performance variation was observed after five consecutive cycles, demonstrating the excellent stability and reproducibility of the photocatalyst. The enhanced performance of B-TCN60 can be attributed to its unique structural and electronic properties. The hollow tubular structure of TCN provides a high surface area, which is beneficial for the adsorption of uranium ions. Additionally, the incorporation of hydroquinone into the TCN framework not only improves the light absorption properties of the photocatalyst but also plays a crucial role in the formation of the D-A system. The effective separation of charge carriers within the D-A system minimizes recombination losses and maximizes the efficiency of the photocatalytic process. The study’s findings underscore the potential of D-A organic semiconductor photocatalysts in addressing environmental challenges associated with nuclear waste, while also enhancing the recovery of valuable uranium resources. The novel approach of utilizing a D-A system in the photocatalyst design opens new avenues for the development of advanced materials with superior photocatalytic performance. The innovative use of template-free self-assembly techniques to fabricate hollow tubular g-C3N4 and the successful synthesis of the B-TCNx photocatalyst represent significant advancements in the field. The high removal efficiency, stability, and reproducibility of B-TCN60 highlight its potential for practical applications in environmental remediation. This work not only contributes to the field of environmental remediation but also offers a sustainable solution to the global issue of nuclear waste management.

The development and application of nuclear energy is often considered as a potential solution to meet the increasing energy demand. However, it is important to acknowledge that the utilization of nuclear energy resources and the treatment of nuclear waste pollution pose significant challenges that require careful consideration and management. Therefore, it is crucial to address the challenges of uranium pollution treatment and uranium resource recovery to ensure the sustainable development of nuclear energy. The technology of photocatalytic reduction has been found to have a synergistic adsorption reduction ability, which allows it to overcome the thermodynamic limitations of single adsorption removal. As a result, photocatalytic reduction technology is widely recognized as having great potential in the removal and recycling of uranium in nuclear waste liquid. One of the key factors for the effective application of this technology is the acquisition of a catalyst with high photocatalytic reduction ability. Nitride carbon materials are considered an ideal photocatalyst for photocatalytic reduction of U（Ⅵ） due to their excellent photochemical properties, excellent physicochemical adjustability, and good chemical stability. However, the pure g-C3N4 photocatalyst still suffers from its low separation efficiency of photogenerated charge carriers, which results in unsatisfactory photocatalytic activity. In recent years, research on modifying and applying carbon nitride has provided in-depth insights into the reduction of uranium through photocatalysis. Discussing the strategy of modifying C3N4, constructing heterojunction nanostructures, and utilizing them for the photocatalytic reduction of uranium, along with the mechanisms involved. This review summarizes the recent significant progress on the design of g-C3N4-based heterostructure photocatalysts and their special separation/transfer mechanisms of photogenerated charge carriers. On the one hand, according to the key steps of photocatalytic uranium reduction, modification strategies using g-C3N4 photocatalysts can be classified into the following groups: morphology modification, band-structure regulation, and heterostructure construction. Moreover, according to the different transfer mechanisms of photogenerated charge carriers between g-C3N4 and the coupled components, the g-C3N4-based heterostructure photocatalysts can be divided into the following categories: g-C3N4-based conventional Type-Ⅱ heterojunction, g-C3N4-based Z-scheme heterojunction, g-C3N4-based S-scheme heterojunction, and g-C3N4/metal heterostructure. We also focused on the structure-activity relationship between the modification of photocatalytic materials based on carbon nitride and their photocatalytic reduction performance for U（Ⅵ）, as well as the mechanism of their catalytic reduction removal. Finally, this section offers concluding remarks and prospects for exploring the challenges and opportunities faced by advanced carbon nitride-based photocatalytic materials in the removal of uranium pollution and the recovery of uranium resources. It also provides directions for future breakthroughs.

With the rapid development of nuclear energy, uranium as the main element of nuclear energy production, its source has been widely explored. At present, uranium resources mainly come from uranium mining, and a lot of radioactive uranium containing wastewater is produced in the process of uranium mining. Until now, the treatment technology of uranium mine wastewater is still in the research and development stage in China, which leads to the storage of a large amount of uranium mine wastewater and the discharge of nuclear waste liquid, which poses a threat to human health and the environment due to the comprehensive effect of chemical toxicity and radiation toxicity. On the other hand, other metal cations in uranium wastewater, such as Ca2+ and Mg2+, compete with U(Ⅵ) for active sites, making it difficult for most treatment methods to effectively recover uranium resources from uranium wastewater. Therefore, how to effectively treat radioactive uranium mine wastewater is full of challenges. Photocatalysis is a kind of green environmental protection technology with natural selectivity to non-variable valence ions, which can precipitate the soluble U(Ⅵ) in wastewater. The photocatalysis technology is expected to overcome the competition between metal cations and uranium for active sites, and realize the efficient extraction of U(Ⅵ) in uranium mine wastewater. In this study, ZIF-8-derived Zinc@iron oxide(D-ZnO@FexOy) heterostructures were prepared by impregnation of metal salt solution and high-temperature pyrolysis using ZIF-8 as a precursor for photoassisted reduction of U(Ⅵ) in uranium ore wastewater. The electron transport mode of D-ZnO@FexOy in S-scheme heterojunction is deduced by calculating the work function and band structure. Under photoexcitation, the direction of electron flow changes, the useless electrons and holes recombine at the interface, and the electrons and holes with strong redox ability are retained and participate in the photocatalytic reaction. Compared with D-ZnO and FexOy, this kind of spatially separated photogenerated electrons and holes have stronger redox ability and longer electron lifetime. Meanwhile, the internal electric field formed at the heterojunction interface can effectively enhance the directional electron migration, providing a strong power for promoting the photoassisted reduction of uranium. Therefore, compared with iron oxide(FexOy) and ZIF-8-derived ZnO(D-ZnO), the S-type heterostructure D-ZnO@FexOy exhibits stronger photoassisted uranium reduction ability(>95%) in the presence of multiple competing ions, and the material has good anti-interference and stability. High U(Ⅵ) removal performance(above 86%) is maintained after 5 cycles. The mechanism study shows that hydroxyl radical and superoxide radical are the main active species of photocatalytic reduction of U(Ⅵ). U(Ⅵ) is deposited on the surface of the material in the form of (UO2)O2•2H2O crystals. This study provides a valuable way to explore the photocatalyst with high efficiency photoelectron separation to reduce U(Ⅵ).

Extracting uranium from seawater is an effective strategy for sustainable nuclear fuel supplementation. Uranium in seawater mainly exists in the form of hexavalent uranyl(U(Ⅵ)), although the total amount is large, the mass fraction of U(Ⅵ) is only 3.3×10−9, and many metal ions coexist with uranium. Extracting uranium from seawater is extremely challenging. Electrochemical seawater uranium extraction has become an emerging method for seawater uranium extraction due to its advantages over physical and chemical adsorption processes, such as fast reaction rate, strong anti-interference ability, and simple desorption. However, due to the lack of research on the structure-activity relationship between catalysts and uranium extraction performance, the rational design of highly active electrocatalysts remains a challenge. In this work, we proposed an interface bonding strategy by using a simple hydrothermal method to bond the {2 2 2} fact of octahedral Fe3O4 to the {0 0 2} fact of MoS2. This significantly improves the electron transfer rate at the interface and the cycling stability of Fe3O4, verifying the feasibility of interface bonding for the electrochemical extraction of uranium from seawater. After 7 hours of electrochemical extraction in a simulated solution, the extraction efficiency of uranium can reach 96%. Meanwhile, the experimental results of coexisting ion extraction of uranium indicated that MoS2/Fe3O4 has good selectivity for uranium and anti-interference ability against coexisting ions. Electrochemical extraction is also performed in 10 L natural seawater with a yield of 27.2 μg. The extraction amount of uranium is 5.44 mg/g. A series of characterizations such as XPS and HRTEM, show that Fe3O4 is dispersed on the surface of MoS2 and effectively bound through interfacial interactions. This dispersion effectively solves the aggregation problem of Fe3O4, and the stability of MoS2 structure ensures the cycling stability of Fe3O4. By combining the MoS2 and Fe3O4 at the interface, an efficient electron transfer channel can be constructed, accelerating electron transfer and achieving the goal of simultaneously improving the selectivity, stability, and electron transfer rate of the catalyst. Therefore, the interfacial regulation strategy proposed in this work utilizes the synergistic effects of different components in the composite material to achieve stability and the cyclicity of the catalyst in seawater uranium extraction. At the same time, the interface control strategy will also provide a feasible solution for achieving efficient reduction and extraction of uranyl in a series of complex environments such as seawater. And the electron transfer path and the species change of uranium during catalytic reduction need to be further explored in the mechanism analysis in this work.

In this work, the coordination chemistry of the uranyl ion(\begin{document}${\mathrm{UO}}_2^{2+} $\end{document}) with N, N-dimethyl-diglycolamic acid(HDMDGA, HLI) and N, N-diethyl-diglycolamic acid(HDEDGA, HLII) has been systematically studied through thermodynamic and structural analysis, by means of both potentiometric and spectroscopic titration, as well as Raman spectroscopy and X-ray diffractometry. The protonation constants of L−(L=LI, LII) and the stability constants of the uranyl complexes were determined by potentiometric and spectroscopic titrations in 1.0 mol/L NaClO4, with the molar absorption spectra of all species deconvoluted in the process of the latter titration. Besides, the standard Raman spectra of various complexes were confirmed by Raman spectroscopic titration. Furthermore, the single crystal of compound \begin{document}${\mathrm{UO}}_2{\mathrm{L}}^{{\mathrm{II}}}_2 $\end{document} was obtained by slow evaporation of aqueous solution containing uranyl ion and LII ligands at room temperature. X-ray diffraction analysis shows a monoclinic crystal system in P21/c space group, with lattice parameters: a=15.5096(6) Å（1 Å=0.1 nm）, b=7.7934(3) Å, c=11.3732(4) Å, α=90°, β=97.388(4)°, γ=90° and Z=2. Although both ligands show a similar structure and protonation constant, the different values of stability constant in aqueous solution and the different bond length of U-O in two complexes indicate the distinct coordination ability for two ligands with \begin{document}${\mathrm{UO}}_2^{2+} $\end{document}, where HDEDGA performs better. Like the crystal structure of \begin{document}$ {\mathrm{UO}}_2{\mathrm{L}}^{{\mathrm{I}}}_2$\end{document}, the ligand LII in the \begin{document}${\mathrm{UO}}_2{\mathrm{L}}^{{\mathrm{II}}}_2 $\end{document} complex coordinates with \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} in a tridentate manner, with three oxygen atoms(amide oxygen, ether oxygen and carboxylic acid oxygen) coordinating with the linear \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} at the equatorial plane. In addition, the diffuse reflectance spectra of the \begin{document}${\mathrm{UO}}_2{\mathrm{L}}^{{\mathrm{II}}}_2 $\end{document} crystal show characteristics significantly different from the absorption spectra of the corresponding complex in the aqueous solution. Meanwhile, the Raman shift of the characteristic peak of uranyl ion between hydrated uranyl ion and the 1∶1 complex(U∶ LII) is significantly larger than that between 1∶1 and 1∶2. Therefore, it is speculated that the structure of the 1∶2 complex in aqueous solution is supposed to be different from that in the solid crystal.

Photocatalytic technology can use photogenerated electrons to reduce easily soluble U(Ⅵ) to insoluble U(Ⅳ). In this work, hierarchical macro/mesoporous g-C3N4-TiO2 composites were synthesized without the introduction of organic templates or auxiliary additives, and were used for photocatalytic reduction of U(Ⅵ). The morphology, structure and optical properties of g-C3N4-TiO2 composites were studied by X-ray diffractometer(XRD), scanning electron microscope(SEM), automatic specific surface area physical adsorption instrument(BET), ultraviolet-visible diffuse reflectance spectrometer(UV-vis DRS) and other advanced characterization equipment. The photocatalytic reduction of U(Ⅵ) of g-C3N4-TiO2 composites was studied by photocatalytic experiments. The results show that g-C3N4-TiO2 composites have the advantages of hierarchical macro/mesoporous TiO2 and g-C3N4, not only have a large specific surface area(174.68 m2/g) and pore channels, but also have a wider light absorption range. Therefore, the removal rate of g-C3N4-TiO2 composites on U(Ⅵ) is as high as 98.4% within 15 min. This work provides new ideas for the treatment of uranium-containing radioactive wastewater.

Photocatalytic assisted uranium extraction technology is a rapidly developed technology for uranium extraction from wastewater and seawater in recent years, which can significantly improve the extraction capacity and extraction rate of uranium. However, the activity of most photocatalysts in air atmosphere is inhibited, which hinders the practical application of this technology. Based on this, this paper discusses the latest progress of photocatalytic assisted uranium extraction technology in air atmosphere, focusing on the analysis of different mechanisms and product characteristics of photocatalytic assisted uranium extraction in air atmosphere, especially the photoreaction and chemical reaction mechanism in the absence of catalyst. There are mainly two mechanisms for the photocatalysis assist uranium extraction. The first one is based on the photocatalytic reduction of U(Ⅵ) to U(Ⅳ). Under illumination, electrons and holes pairs are generated on photocatalysts, and the electrons could reduce the soluble \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} to insoluble uranium oxide(UO2). However, under air atmosphere, at the presence of oxygen, the newly formed UO2 could be oxidated back to \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} and dissolved into solution, resulting in the decrease of uranium extraction performance. Therefore, this mechanism is usually applied under inert atmosphere. Although with proper design of photocatalyst, the oxygen could be covert to \begin{document}${ · {\mathrm{O}}_2^- } $\end{document} to further reduce \begin{document}${\mathrm{UO}}_2^{2+} $\end{document}, the performance is still not comparable with that under inert atmosphere. The other recently developed photocatalysis assisted extraction mechanism is based on the convert of soluble \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} to uranium peroxide((UO2)O2•xH2O), which can work well under air atmosphere. Under light illumination, hydrogen peroxide(H2O2) can be first produced with the assist of efficient photocatalysts or the photoactivity of \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} itself. Then H2O can react with to \begin{document}${\mathrm{UO}}_2^{2+} $\end{document} form insoluble uranium peroxide. As uranium peroxide is stable under air and oxygen may contribute to the formation of H2O2, this mechanism can obtain excellent performance under air. Researchers have developed composite materials such as carbon nitride, carbon dots, graphene aerogels, and metal-organic frameworks(MOFs), which exhibit superior uranium removal performance under aerobic conditions. Besides, research on uranium extraction via photocatalysis under air is still in its infancy, and the specific reaction mechanisms may vary under different environments, necessitating further investigation. Based on the mechanism of uranium extraction via the photo-assisted transformation to uranium peroxides, the design of catalysts and uranium extraction materials will be greatly broadened. Combined with the discussion of the reaction mechanism of uranium extraction under light conditions and the design of catalyst materials, we hope to provide inspiration for researchers to develop highly efficient uranium extraction catalyst and mechanism research under air atmosphere.

In this work, molten salt method was used to prepare highly dispersed graphitic carbon nitride(WSGCN), and chemical reduction method was used to load Cu nanoparticles on WSGCN to prepare Cu-WSGCN composites. FTIR, XRD, XPS, TEM, SEM, ICP-AES, UV-vis DRS, PL spectroscopy, ESR and EIS characterization methods were carried out to investigate the structure and photoelectric properties of the photocatalyst. The results show that compared with WSGCN, Cu-WSGCN has a larger light absorption range and a narrower band gap. In addition, the presence of Schottky barriers at the interface between Cu nanoparticles and WSGCN promotes charge transfer and separation of photogenerated carriers, which improves the photocatalytic ability. The uranium removal rate of Cu-WSGCN composite is relatively high(81.07 %) when the load of Cu nanoparticles is 1%. After three cycles of photocatalytic uranium reduction experiments, the uranium removal rate by 1%Cu-WSGCN can still reach 75.96%, which provides a useful reference for the development of novel materials with high efficiency photocatalytic removal of uranium.

Uranium is the main fuel of nuclear power, and the removal of uranium from uranium-containing wastewater is important for environmental protection and resource recovery. Photo-induced uranyl ion removing is an economical and efficient method to remove U(Ⅵ) from uranium-containing wastewater. Many materials have been used for photo-induced reduction of U(Ⅵ). However, the practical application of most materials is still limited by many factors, such as the complexity of its synthesis process, the harsh conditions required, and the poor selectivity and reusability in the photocatalytic process. More importantly, most materials can only be photocatalyzed under the protection of an inert atmosphere. In the presence of oxygen, the photocatalytic product uranium dioxide(UO2) is unstable and easily oxidized resulting in reduced removal effect, so it becomes particularly vital to find an effective catalyst. Carbon dots(CDs) are a new type of carbon-based materials with excellent fluorescence performance, good water solubility and biocompatibility. However, due to the small size and hydrophilicity of the CDs, it is difficult to separate from water. It needs to be combined with other solid materials when applied. The application of CDs to the photocatalytic removal of uranyl ions in water has rarely been studied. Silica(SiO2) is an ideal loader due to its excellent mechanical strength and irradiation stability, as well as its large specific surface area and easy modification. In this paper, a blue carbon dot was prepared by solvothermal method and CDs/SiO2 composites were synthesized by sol-gel method. The morphology of the composite was characterized by scanning electron microscopy(SEM) and transmission electron microscopy(TEM) technologies, and their application in photocatalytic removal of uranium were studied. Under visible light irradiation, CDs/SiO2-b can remove more than 95% of uranium in 100 min. Experiments have found that the photo-precipitation rate of silica to uranium after the introduction of carbon dots is about 5.8 times of that of the pure silica, and uranium can be transformed into solid product of (UO2)O2•2H2O under air atmosphere, with a removal capacity of more than 800 mg/g. The morphology and structure of the photocatalytic products were characterized by SEM and XPS technology, and the solid products were easy to separate and remove. In order to evaluate the practical application of CDs/SiO2 light-induced reduction of uranium under visible light irradiation, pH and other influencing factors were systematically studied. Moreover, the removal efficiency of uranium is higher 85% after 5 cycles of recycling, showing excellent recycling performance. CDs/SiO2 composites are simple to prepare and can efficiently remove uranyl ions in water through photoinduction, which provides a new method and material for photoinduced removal of uranium.

The photocatalytic conversion of soluble U(Ⅵ) to insoluble U(Ⅳ) is regarded as an effective method for the separation of solution uranium. During the photocatalytic reactions, the design of photocatalyst plays a role. As a metal free polymer semiconductor, carbon nitride(CN) has attracted increasing attentions in photo-catalytic reduction of U(Ⅵ) under visible light irradiation due to its low cost, easy preparation, excellent physicochemical stability and adjustable structure. However, the application of carbon nitride in photocatalytic U(Ⅵ) reduction is limited by its low photocatalytic reduction efficiency, which is caused by the poor reactive sites low separation rate of charge carriers, and slow transport efficiency of electrons. This study aimed to evaluate the transformation of U(Ⅵ) in aqueous solution over Y-doped CN(YCN). YCN photocatalysts with different amount of Y3+ were prepared by in situ doping to modify the energy band structure and physicochemical properties of carbon nitride. It was revealed that the presence of Y3+ changed the in-plane periodic topology and inter-layer stacking structure of the tri-s-triazine unit of carbon nitride, resulting in the incomplete polymerization of the tri-s-triazine unit. The doping of Y3+ lead to the formation of porous structure in YCN, which increases the specific surface area and the active sites. Comparing with pristine CN, YCN showes enhanced absorbance for light and increases separation rate of charge carriers. The average fluorescence life is subsequently increased under light irradiation, which is 1.8 times for YCN2 than the pristine CN. The EPR spectra demonstrates that, compared to CN, significantly more \begin{document}$ · {\mathrm{O}}_2^- $\end{document} radicals and less \begin{document}$· {\mathrm{OH}} $\end{document} radicals are generated on YCN2 under light irradiation. The free radical trapping experiments verifies that \begin{document}$ · {\mathrm{O}}_2^- $\end{document} radicals act as the dominant reactive species for the reduction of U(Ⅵ) and the small amount of other radicals do not bring obvious influence. The enhanced generation of \begin{document}$ · {\mathrm{O}}_2^- $\end{document} radicals on YCN2 therefore provides favorable conditions for the photocatalytic reduction of U(Ⅵ). When using methanol as a sacrificial agent, it can remove about 95% of U(Ⅵ) within 20 min for the YCN2-containing system under light. The rate of the photocatalytic reduction of U(Ⅵ) on YCN2(0.112 min−1) is 5.3 times higher than CN(0.021 min−1). Analysis of the products reveals that water-soluble U(Ⅵ) is reduced in the photocatalytic reaction, with approximately 80% U(Ⅳ) and 20% U(Ⅵ). The soluble U(Ⅵ) is mainly reduced to insoluble UO2+x deposited on the surface of YCN by \begin{document}$ { · {\mathrm{O}}_2^- } $\end{document} radicals. This study improves the photocatalytic performance of CN for the reduction of U(Ⅵ) by Y3+ doping.

Uranium, as the most important fuel for nuclear power operation, is crucial to ensure the sustainable development of nuclear power. However, the supply-demand contradiction of uranium resources in China has become increasingly prominent, and the gap needs to be filled by overseas development and international market procurement. The photoreduction and electroreduction of uranium under complex conditions are mainly targeted at uranium containing radioactive wastewater, real seawater, and other systems. Uranium containing radioactive wastewater comes from the processes of uranium mining, uranium enrichment, uranium conversion, and manufacture of nuclear fuel elements, with the characteristics of complex interfering ions. Although the total amount of uranium in seawater is very large, the concentration of uranium in seawater is low, making the extraction of uranium from seawater extremely challenging. On the one hand, the reserves of uranium in seawater are nearly a thousand times higher than those on land; on the other hand, the entire application process of the nuclear industry produces a large amount of uranium containing radioactive wastewater. If efficient separation of uranium from seawater and uranium containing radioactive wastewater can be achieved, it can promote the secondary supply of uranium resources and alleviate the supply-demand contradiction of uranium resources in China. Therefore, the development of uranium recovery and extraction technology from seawater and uranium containing radioactive wastewater is important for the sustainable development of the nuclear industry. This paper reviews the recent research progress in separating uranium in complex environments such as seawater and uranium containing radioactive wastewater. In terms of uranium speciation analysis, it describes the coordination environment of complex environmental uranyl and summarizes the advantages of photocatalysis and electrocatalysis in the fields of uranium extraction from uranium containing radioactive wastewater and seawater. In terms of designing photocatalysts, strategies such as element doping, metal loading, defect engineering, and introducing heterojunctions have been summarized for the preparation of photocatalytic semiconductor materials. The modification of functional groups on heterojunctions to regulate their energy band structure had introduced, which improved the overall performance of the material. The integration of selective adsorption and catalytic reduction, electrochemical methods can reduce soluble uranyl ions to neutral and insoluble products for separation, with advantages such as fast kinetics, wide extraction concentration range, and large separation capacity. However, there are also many key technical challenges in the practical application process, such as the competition between multiple cations and uranyl ions in complex systems, and the problem of excessive energy consumption caused by the competing reaction of water splitting during the cathodic uranium extraction process. In terms of electrocatalysis, various aspects such as electrode carrier selection, electrochemical device design, defect engineering, surface engineering, interface engineering, and microbial electrochemistry have been summarized to design electrocatalytic materials. In terms of key technical bottlenecks, combining photocatalysis and electrocatalysis technology with challenges in complex scenarios such as uranium speciation analysis, material functionalization design, intermediate reaction species analysis, uranium extraction mechanism analysis, cost control, and real-world application outcomes, relevant research have focused on challenges such as efficient photocatalytic reduction of uranium under natural light, identification of intermediate uranium species, uranium extraction from uranium containing radioactive wastewater, and seawater extraction from real ocean environments.

In this work, a novel graphite-based electrochemical filter was developed for the efficient and environmentally friendly treatment of uranium tailings leachate. The filter utilizes graphite particles as filler and carbon felt as a conductor, powered by a DC power supply and driven by a peristaltic pump. In a non-circulating continuous operation filter experiment, uranium tailings leachate was tested for uranium removal efficiency under different operating parameters such as voltage and residence time, using both synthetic wastewater and actual uranium mine wastewater. This study is based on the fundamental principles of metal electrochemical reduction. The efficacy of this device for the continuous flow treatment of uranium tailings leachate was systematically investigated. The mechanism of uranium tailings leachate treatment by the electrochemical filter was elucidated through electrochemical analysis and product characterization. The results highlight that voltage and hydraulic retention time are critical factors influencing the efficiency of electrochemical filter treatment. Specifically, 4.0 V and 10 hours were identified as the optimized voltage and suitable hydraulic residence time, respectively, for the treatment of uranium tailings leachate using the electrochemical filter, resulting in a uranium removal rate exceeding 97%. In actual uranium tailings leachate applications, the maximum extraction rate can reach 5275 μmol/(m3∙h), confirming the feasibility of electrochemical filter in removing uranium from actual uranium tailings leachate and its good selectivity in complex water quality applications, the device can be quickly applied to uranium tailings leachate collection facilities and achieve in-situ uranium extraction. The voltage increase can significantly enhance the uranium extraction performance and can be portablely deployed in uranium mine water. In-situ uranium processing and recovery is achieved in processing and collection facilities. Characterization techniques such as field emission scanning electron microscope-energy spectrum analyzer(FESEM-EDS) and X-ray photoelectron spectrometer(XPS) were employed to analyze the reaction products on the graphite particles, revealing that uranium was evenly distributed on the surface of graphite particles and exhibits a stable crystal structure, the main mechanism responsible for uranium removal was adsorption-reduction, with uranium recovery products deposited on the electrode surface in the form of a mixture of U(Ⅳ) and U(Ⅵ). A cost estimation shows that the operational cost of extracting uranium from uranium tailings leachate using this device falls within the range of 176.6 ￥/kgU to 587.5 ￥/kgU. This cost is significantly lower than that of conventional land-based uranium resource development, making it economically viable. This research provides both theoretical and technical support for the efficient and environmentally friendly treatment of uranium tailings leachate.

Abstract The human insulin gene modified with a C-peptide was synthesized according to the plant-preferred codon, and a fusion gene expression vector of insulin combined with green fluorescent protein (GFP) was constructed. The optimization of the flax callus culturing was undertaken, and a more efficient Agrobacterium-mediated genetic transformation of the flax hypocotyls was achieved. The critical concentration values of hygromycin on the flax hypocotyl development, as well as on its differentiated callus, were explored by the method of antibiotic gradient addition, and the application of antibiotic screening for the verification of positive calluses was assessed. The fusion gene of insulin and GFP was successfully inserted into the flax genome and expressed, as confirmed through polymerase chain reaction and Western blotting. In conclusion, we have established a flax callus culture system suitable for insulin expression. By optimizing the conditions of the flax callus induction, transformation, screening, and verification of a transgenic callus, we have provided an effective way to obtain insulin. Moreover, the herein-employed flax callus culture system could provide a feasible, cheap, and environmentally friendly platform for producing bioactive proteins. Graphical Abstract

A copper-catalyzed three-component reaction of diazo compounds, nitriles, and azodicarboxylates to construct 2,3-dihydro-1,2,4-triazoles is reported. Key to the success is the utilization of azodicarboxylates to trap the in-situ formed nitrile ylides from diazo compounds by [3 ​+ ​2]-cycloaddition. Both the acceptor-only and donor-acceptor diazo compounds are all tolerated to the strategy. The synthetic value of this protocol is illustrated by gram-scale synthesis and valuable transformation of the obtained 2,3-dihydro-1,2,4-triazoles.

A dehydroxylative ring-opening Giese reaction of cyclobutanone oximes enabled by photoredox/Ti dual catalysis has been reported in this work. This protocol avoids the prefunctionalization of oximes and the use of stoichiometric triarylphosphine reagents. It also features mild conditions, broad substrate scope and good functional group tolerance. The gram-scale reaction, product derivatization, late-stage functionalization of complex pharmaceutical and natural product derivatives, and oligopeptide modification exhibit the potential application of this methodology in synthetic chemistry.

Two types of poly-porphyrin-based heterogeneous photocatalysts including insoluble polymer and water-soluble nanoparticles exhibited excellent photocatalytic activity in visible-light-induced dehydrogenation in water. The extremely low catalyst loading (0.01 ​mol%) of water-soluble nanoparticles provided so far the highest turnover frequency (TOF) value (333 h-1) for such transformation among reported records.

Catalytic fixed-bed is an efficient and facile system for scalable organic synthesis due to its continuous and fast flow operation process. As a key unit in the fixed-bed system, catalytically active packing materials are required to possess some properties, such as high activity, excellent stability, and porous packing structure. Herein, we prepare a fibrous fixed-bed catalyst by anchoring Pd nanoparticles on N-doped graphene fiber (NHG) (Pd/NGF). Due to the porous and loose packing structure, the resultant Pd/NGF catalyst can be easily filled into the continuous-flow reactor to construct a fixed-bed system with low flow resistance. The corresponding catalytic fixed-bed system exhibits a favourable flow rate (8 ​mL/min) and excellent durability toward reduction reactions of N-containing unsaturated compounds to produce aromatic amines. This work provides a new design concept of fibrous fixed-bed catalysts with dual-active components (i.e., graphene-derived active materials and metal nanoparticles) and catalytic organic synthesis in a continuous-flow process.

A highly efficient, transition-metal- and light-free approach to polyheterocycles via regioselective cascade radical cyclization is developed. The redox-neutral protocol has a broad substrate scope with good functional group tolerance and probably undergoes a SET process, which is initiated by catalytic amounts of quinone in combination with 2.0 equiv. of Cs2CO3.

Asymmetric ring-expansion reactions of silacyclobutanes (SCBs) with alkynes have evolved as one of the powerful protocols for the construction of silicon-stereogenic compounds. However, the achievement of highly enantioselective annulation of SCBs with terminal alkynes remains a challenge. Herein, we report a rhodium-catalyzed asymmetric annulation reaction of SCBs with terminal alkynes, which relies on the newly identified chiral sulfinamide phosphine ligand Ming-Phos. This catalytic system exhibits unique effects under mild conditions, leading to the direct synthesis of structurally diverse chiral silacycles in moderate to good yields with high enantioselectivities (up to 95% ee).

We herein reported a sustainable synthesis of 3,3-disubstituted oxindoles via a Michael-type reaction based on the CuBr-catalysed capture of carboxylic oxonium ylides with isatylidene malononitrile. The reaction is characterized by a high atom economy and low economic constraints. The catalyst CuBr could be conveniently recyclized. The products of the reaction were found to be inhibitory against Na ion channels. We expect the reaction to shed the light on synthesis of biologically interesting molecules directed by principles of green chemistry.

The nitrile compounds are present in a variety of biologically active natural products and pharmaceuticals, and the nitrile groups are versatile synthetic intermediates to other functionalized compounds. Herein, the asymmetric reduction of α, β-unsaturated nitriles with water as a hydrogen source is reported. The reaction is catalyzed by the complex of [Ir(COD)Cl]2 and (Ra, S)-Ph-Bn-SiPhox, and allows the preparation of useful enantioenriched chiral 3,3-disubstituted propionitriles with high optical purities in mild conditions.