Material Absorption Research Articles

Characteristics of constant pressure dehydrogenation and construction of linear diffusion model for solid hydrogen storage materials: A case study of TiMn1.5 alloy

Solid-state hydrogen storage is considered to be the most promising hydrogen storage technology because of its high volumetric capacity and good security. The process of hydrogenation and dehydrogenation of solid hydrogen storage materials can be characterized by a diffusion kinetic model, which can be used to guide the safe and efficient application of hydrogen storage materials. Currently, experimental study on the dehydrogenation characteristics under constant pressure outer boundary condition has not been carried out methodically, and a simple and reliable diffusion kinetic model under this condition should be established based on the experimental results. In this study, an experimental platform for hydrogen absorption and constant pressure dehydrogenation of solid hydrogen storage materials was independently established. The TiMn1.5 alloy and its interstitial hydrides were taken as the experimental research objects to conduct constant pressure dehydrogenation tests, and the dehydrogenation properties at different temperatures were systematically studied. The results show that the dehydrogenation rate decreases with the increase of testing time. The ultimate capacity of hydrogen release increases first and then decreases with the increasing temperature, reaching the maximum value at 30 °C. It is found that the diffusion coefficient increases linearly with time during constant pressure dehydrogenation process. On this basis, a linear diffusion kinetic model is established. The initial diffusion coefficient D0 calculated by the new model has a quadratic polynomial relationship with temperature, and the increase coefficient α of diffusion coefficient has a linear relationship with temperature. According to the mathematical expressions, the dehydrogenation process of TiMn1.5 alloy at different temperatures can be predicted. The research results can provide theoretical guidance for the safe, efficient and controllable application of hydrogen storage materials.

Impact Absorption Power of Polyolefin Fused Filament Fabrication 3D-Printed Sports Mouthguards: InVitro Study.

This study aims to evaluate and compare the impact absorption capacities of thermoformed ethylene vinyl acetate (EVA) mouthguards and 3D-printed polyolefin mouthguards used in sports dentistry applications. The objective is to determine whether 3D-printed polyolefin mouthguards offer superior impact toughness compared to traditional EVA mouthguards commonly used in sports settings. Six material samples were assessed: five pressure-formed EVA mouthguards (PolyShok, Buffalo Dental, Erkoflex, Proform, and Drufosoft) and one 3D-printed synthetic polymer (polyolefin). The materials were evaluated using a modified American Society for Testing and Materials (ASTM) D256 Test Method A for Izod pendulum impact resistance of plastics. Polyolefin samples were 3D-printed using fused filament fabrication (FFF) technology. Notably, the FFF process included samples printed with notches placed either parallel or perpendicular to the build direction. This orientation served as a study factor, allowing for comparison of material behavior under different printing conditions. Impact testing was conducted using an Izod impact tester to assess the materials' performance under controlled impact conditions. The study achieved a high power (1.0) in power analysis, indicating strong sensitivity to detect significant differences. Among molded materials, PolyShok showed significantly lower impact toughness compared to others (p = 0.06). The mean impact absorption of EVA materials was 5.4 ± 0.3 kJ/m2, significantly lower than polyolefin materials, which demonstrated 12.9 ± 0.7 kJ/m2 and superior performance (p = 0.0). Horizontal-notched polyolefin samples exhibited higher impact strength compared to vertical-notched samples (p = 0.009). 3D-printed polyolefin mouthguards exhibited significantly higher impact toughness than thermoformed EVA mouthguards. While EVA materials demonstrated structural robustness, their lower impact resistance and observed tearing in other test specimens suggest the need for alternative testing standards to better reflect real-world conditions. 3D-printed mouthguards fabricated with build orientations perpendicular to the direction of impact demonstrate significantly enhanced impact absorption. Further research into manufacturing methods and testing protocols is recommended to optimize mouthguard performance under impact scenarios.

Hollow N doped carbon/SiCN hierarchical structures for thermostable electromagnetic absorptions

Electromagnetic absorption materials present widespread application prospects. The thermal oxidative aging issues for electromagnetic absorption materials have received little attention. In this paper, N-doped carbon tubes, and the SiCN ceramics are combined to realize thermostable electromagnetic absorptions. The hierarchical structures show significantly enhanced broadband electromagnetic absorption with an optimal RL of -53.61 dB at 14 GHz under a thickness of 2 mm. The effective electromagnetic absorption bandwidth reaches 5.53 GHz, and the coverage range is 11.88–17.41 GHz. More importantly, after 1 h calcination at 300 °C, the optimum RL of NCT/SiCN-1 h is still -45.67 dB under the thickness of 2.5 mm. The effective electromagnetic absorption bandwidth increases to 5.95 GHz, and the coverage range is 10.69–16.64 GHz. Our work proves the possibility for improving the thermostable electromagnetic absorptions of carbon materials, and provides referencing ways for the design of thermostable electromagnetic absorption materials.

Facade Design and the Outdoor Acoustic Environment: A Case Study at Batna 1 University

The relationship between architectural design and outdoor acoustic environments remains underexplored, particularly in educational spaces where noise levels impact comfort and usability. This study investigates the impact of building facade height on the outdoor acoustic environment in university courtyards. Acoustic measurements were conducted in two courtyards at Batna 1 University, each surrounded by buildings with distinct facade heights. Key acoustic parameters, including reverberation time (RT), early decay time (EDT), rapid speech transmission index (RaSTI), Definition (D50), and sound pressure level (SPL) attenuation were evaluated at specified source-receiver distances. The results reveal a strong correlation between RT20 and distance at higher frequencies due to building facade reflections, while lower frequencies are more influenced by geometric configuration and material absorption properties. The results demonstrate that RT and EDT increase logarithmically or polynomially with distance, especially at higher frequencies (2000–4000 Hz), due to the decrease in direct sound energy and increase in reflected sound amplitude. Taller building facades lead to longer RT and EDT values compared to lower heights. D50 and RaSTI decrease polynomially with increasing source–receiver distance, with lower values observed in the courtyard with taller facades, indicating reduced speech clarity. The SPL attenuation is influenced by surrounding geometry, with the least reduction in the courtyard with lower facade heights, followed by the taller facade courtyard, contrasting with semi-free field conditions. These findings highlight the significant role of building facade height and architectural elements in shaping the acoustic characteristics of outdoor spaces, providing valuable insights for designing acoustically comfortable urban environments, particularly in educational settings.

Terahertz laser-fabricated all-polymer hole arrays with high-quality quasi-bound states in the continuum

Abstract Dielectric metasurfaces promise to realize ultrahigh-quality (Q) resonances due to their ultralow material absorption. Most of them are silicon-based metasurfaces, requiring complex fabricated steps and thus suffering high costs. Laser etching processing has simple steps accompanied by low time consumption and exemplary processing efficiency. Here, an all-polymer metasurface based on hole arrays fabricated by laser processing has been proposed and investigated. Such metasurfaces achieve sharp quasi-bound states in the continuum (quasi-BICs) via breaking structural symmetry, form two annular circulation electric fields in different directions, and thus allow strong coupling between holes. Owing to the low refractive index of polymer, the calculated Q-factor reaches 9555 while the diameter discrepancy is 4 μm. Simulated results proved that the Q-factors of quasi-BICs can be further improved by reducing the film thickness and refractive indices of materials, which can be predicted by the fitting equation. Also, the fields in holes can be enhanced by reducing the film refractive index. These results in simulations and experiments provide an alternative method for designing high-Q resonators in terahertz regions.

The effect of water absorption and specific gravity of supplementary cementitious materials on required water

The use of supplementary cementitious materials (SCM) is projected to increase because they reduce the global warming potential of concrete. When cement is replaced with SCM, the flow of the mixture may change. The porosity of the paste may also change as the liquid-to-solid volumes change when mass replacement is used. This paper discusses the role of water absorption and the specific gravity of the SCM on the water requirements of a mixture. Over thirty SCMs were tested, including sixteen natural pozzolans, ten coal ashes, three blended pozzolans, and one ground glass. The porosity of the SCM was measured using a drying rate test. The water absorbed by the natural pozzolans ranged from 3.25 to 17.25 %, 5.55–9.25 % for blended pozzolans, 4.10–18.95 % for coal ashes, and 4.20 % for ground glass. The water requirement measured using ASTM C311 ranged from −4.25 to 46.2 %. The specific gravity of the SCM is particularly important when it is significantly different from the specific gravity of the OPC, as this can change the liquid-to-solid volume ratio. Accounting for the absorption of water by the SCM and the specific gravity of the SCM (via volume replacement) resulted in 55 % of the specimens having a water demand within ±5 % of the original mixture to achieve the same flow, and 94 % of the samples had a water demand within ±20 %. This was substantially less than mass replacement. Using volume replacement and accounting for SCM absorption would have water requirements more similar to the original mixtures.

Compressive Mechanical Properties and Energy Absorption of Cubic Spherical Hollow Cellular Material Based on the Rod and Curved Surface Structure

Cellular materials, such as lattices and honeycombs, were widely used for structural protection owing to their excellent mechanical properties. By combining the excellent characteristics of lattice and honeycomb curved surface structures, this study designed a cell called Cubic Spherical Hollow (CSH), which had the advantages of orthogonal isotropy and better spatial connectivity. Inspired by the micro-structural arrangement of bamboo fiber and conch shell, we designed the new CSH cellular materials through the interlayer offset strategy. Then, the effects of interlayer offset on the mechanical properties and compression deformation behavior were explored experimentally and simulatively. Compared with other cellular materials, CSH cellular materials exhibited excellent mechanical properties with higher specific strength and specific modulus. The arrangement offsets of the CSH cells between different layers led to a change in the deformation mechanism from a rod’s compressive mode to a combination of a rod’s compressive mode and curved surface’s bending mode. The initial peak stress and plateau stress decreased with the increased arrangement offsets of the CSH since the extruded protrusions of the structure filled the holes and reduced the lateral expansion behavior of the material in the pressurized environment. This phenomenon also reduced the transverse expansion and prevented the sudden change in stress in the constrained space, indicating that the structural deformation was stable and had excellent cushioning and energy absorption properties. In this study, the cellular material design strategy opens a new avenue for energy absorption.

Emergent Research Trends on the Structural Relaxation Dynamics of Molecular Clusters: From Structure-Property Relationship to New Function Prediction.

ConspectusMolecular clusters (MCs) are monodispersed, precisely defined ensembles of atom collections featured with shape-persistent architectures that can deliver certain functions independently. Their molecular compositions and surface functionalities can be tailored feasibly in a predefined manner, and they can be applied as basic structural units to be engineered into materials with desirable hierarchical structures and enriched functions. The chemical systems also offer great opportunities for the design and fabrication of soft structural materials without the chain topologies of polymers. The bulks of MC assemblies demonstrate viscoelasticity that is used to be considered as the unique feature of polymers, while the MC systems are distinct from polymers since their elasticities are resilient even at temperatures 100 K above their glass transition temperatures. The understanding of their anomalous viscoelasticity and the extended studies of general structure-property relationships are desired for the development of new chemical systems for emergent functions and the possibilities to resolve the intrinsic trade-offs of traditional materials.Meanwhile, general macroscopic functions or properties of materials are related to the transportation of mass, momentum, and/or energy, and they are basically realized or directed by the motions of structural units at different length scales. Structural relaxation dynamics research is critical in quantifying motions ranging from fast bond deformation, bond break/formation, and diffusion of ions and particles to the cooperative motions of structure units. Due to the advancement of measurement technology for relaxation dynamics (e.g., quasi-elastic scattering and broadband dielectric spectroscopy), the structural relaxation dynamics of MC materials have been probed for the first time, and their multiple relaxation modes across several temporal scales were systematically studied to bridge the correlation between molecular structures and macroscopic functions. The fingerprint information from dynamics studies, e.g., the temperature dependence of relaxation time and certain property, e.g., ion conductivity, was proposed to quantify the structure-property relationship, and the microscopic mechanism on the mechanical properties, ion conduction, and gas absorption and separation of MC materials can be fully understood.In this Account, to elucidate the uniqueness of MC materials, especially in comparison with polymers, four topics are mainly summarized: structural features, relaxation dynamics characterization techniques, relaxation dynamics characteristics, and quantified understanding of the structure-property relationship. The capability for new function prediction from relaxation dynamics studies is also introduced, and the typical example in impact resistant materials is provided. The Account aims to prove the significance of relaxation dynamics characterization for material innovation, while it also confirms the potential of MCs for functional material fabrications.

Dynamic Behavior and Energy Absorption of Typical Porous Materials under Impacts.

Porous materials are known for their excellent energy absorption capability and, thus, are widely used in anti-impact applications. However, how the pore shape and size impact the failure mechanism and overall behavior of the porous materials under impact loading is still unclear or limitedly touched. Instead of using homogeneous solids for the porous material model, pores with various shapes and sizes were implanted in a solid to establish the porous materials that have true porous structures, which permits exploration of the local failure mechanism. The results revealed that differently shaped holes have two different dominant deformation modes. And due to their different local stress distributions, they enter the plastic phase earlier and, thus, have higher specific energy absorption. Meanwhile, the model changes from hardening to a quasi-zero stiffness model as the hole size increases. The application of this work can be extended into the field of impact resistance.

Thermochemical Corrosion of Furnace Materials in Atmospheres Containing Ammonia

ABSTRACTFurnace components are made from heat‐resistant materials that must withstand the long‐term effects of the atmospheres used during heat treatment. In a nitriding furnace, the atmosphere usually consists of various gaseous media that react not only with the treated parts but also with the furnace equipment. This leads to thermochemical corrosion, even with carefully selected heat‐resistant and stainless steels or nickel‐based alloys. The present research focuses on determining the long‐term effects of ammonia‐containing atmospheres on the metallic furnace materials AISI 309, AISI 314, Alloy 600, and Alloy 601. The materials studied were exposed to numerous nitriding or nitrocarburizing treatments for more than 10 years to investigate the long‐term effects of repeated contact with ammonia‐containing atmospheres. The surface layers of the samples were characterized by several methods to determine the microstructural changes due to nitrogen absorption. A different nitrogen absorption of the metallic furnace materials from the heat treatment atmosphere, depending on the material properties, could be proven by the investigations.

Defect introduction and interfacial strategies for enhancing microwave absorption in carbon-based materials

Poor impedance matching and a single loss mechanism are typical challenges for carbon-based materials to become efficient microwave absorbers. To address these issues, defect introduction and interfacial strategies are effective methods for enhancing microwave absorption through the micro-mechanism of material interaction with microwaves. Additionally, forming a homogeneous composite material is crucial for achieving good impedance matching. In this study, we used a controlled solvent-thermal method to achieve self-assembled interfacial intercalation, yielding amorphous VOPO4/rGO nanohybrids, which show significantly enhanced microwave absorption properties. The abundant defects introduced by VOPO4 within the amorphous layered composites disrupt the charge distribution, contributing to polarization loss. The graphene nanosheets expose more VOPO4 structural units, facilitating increased conductivity and enriching the microwave absorption mechanism. As a result, the prepared VOPO4/rGO nanohybrids demonstrate outstanding microwave absorption, with the effective absorption bandwidth covering the entire Ku-band (11.6–18.0 GHz) at a thickness of 2.3 mm. This research provides an important reference for understanding the mechanisms that enhance the electromagnetic wave absorption of carbon-based materials.

Upcycling Spent Graphite from Li-ion Batteries into Cu/Expanded Graphite Composites as high-performance electromagnetic wave absorbers.

With the widespread adoption of lithium-ion batteries and modern electronic components in both daily life and industrial production, there is a growing focus on the high-value recycling of spent lithium-ion batteries and the development of absorbents with high electromagnetic wave absorption capabilities. Efficiently regenerating recycling graphite from spent batteries through low-cost methods and utilizing it to prepare high-performance electromagnetic wave absorbing materials holds significant importance in addressing both the utilization of waste graphite and electromagnetic pollution issues simultaneously. This work presents a method to transform spent graphite into expanded graphite with a three-dimensional conductive structure using an enhanced Hummer's treatment and thermal reduction process. Subsequently, Cu/EG composite materials were efficiently prepared through straightforward mechanical ball milling and calcination. The unique honeycomb-like porous structure of expanded graphite facilitates the reflection and scattering of electromagnetic waves, electron transfer, and defect polarization. Additionally, the incorporation of copper nanoparticles improves the conduction loss and enhances interface polarization, allowing for precise tuning of the composite material's absorption performance. The results demonstrate that Cu/EG composite materials exhibit excellent electromagnetic wave absorption performance. The Cu/EG(1:3) sample exhibits effective absorption in the C, X, and Ku bands, achieving a minimum reflection loss (RLmin) of -54 dB and a maximum effective absorption bandwidth (EABmax) of 5.28 GHz. This performance is attained with a thickness of just 2.2 mm and a filler content of only 15 wt.%.

Acoustic materials based on the Gosper curve

In this work, slotted acoustic materials based on a space filling curve called the Peano-Gosper curve are proposed and investigated. The slits in such materials form a complex pattern because they are divided by walls built along lines generated by the Gosper curve algorithm. The pattern can be twisted around an axis normal to its surface to increase the tortuosity inside the material, and therefore, modify its acoustic properties, which can be controlled by the turning angle or pitch of the twist. A highly efficient semi-analytical model has been developed to accurately predict the acoustic properties, in particular the sound absorption of such materials. It only requires a representative part of the pattern, or better, scanning the surface of the fabricated material so that the actual geometry and dimensions (in particular slit widths) are well reproduced in a two-dimensional finite element mesh generated on a representative fluid domain. The mesh is used to solve a dedicated Poisson problem and determine a few key parameters, and the rest of the modelling is based on analytical formulas. Material samples with straight and twisted slit patterns were 3D printed and then measured in an impedance tube to confirm semi-analytical sound absorption predictions.

Poroelasticity and acoustic properties of bio-based materials : from characterization to the understanding of mechanical dissipation effects

The building sector is a key element in reducing the effects of climate change. To operate sustainably and efficiently, solutions based on building materials having a low environmental impact, such as bio-based materials, are needed. In fact, they present high-level multi-functional properties and they capture atmospheric carbon dioxide. However, even if a number of works has examined visco-thermal dissipation effects, the understanding of the mechanical dissipation effects on the acoustic performances of bio-based materials is still incomplete and little data are available in the literature. Therefore, it seems particularly relevant to investigate by experimental characterizations and modelling methods the effects of mechanical dissipation on the acoustic properties of a representative variety of bio-based materials such as vegetal wools, vegetal aggregate stacks and vegetal concretes. To do this, Young's modulus, Poisson's ratio and structural damping were measured on the various typology of materials by a quasi-static analysis method. The non-linear elastic behaviour in compression of bio-based samples is analyzed. Finally, the influence of Young's modulus and structural damping on the acoustic absorption and attenuation properties of bio-based materials is described using modelling approaches.

Hygroscopic effects on sound absorption of multiscale bio-based porous materials

Hygroscopicity is the tendency of a material to absorb moisture from the surrounding environment. This work investigates hygroscopic effects on the sound absorption properties of multiscale bio-based materials. It is shown how moisture can significantly alter their acoustic performance as well as how to recover their original dry-material performance by means of heat treatment, akin to thermal reactivation commonly used in the chemical engineering industry. The results of an experimental campaign, conducted over an extended period of time, is reported. Possible theoretical explanations on the reduced acoustic performance of activated carbons by hygroscopic effects and the achieved improvement, obtained after heat treating the material, are also presented. The results of this work provide useful insights on the long-term acoustic behaviour of multiscale bio-based materials for noise control applications.

Simplification of Johnson-Champoux-Allard-Lafarge model on fibrous materials

The Johnson-Champoux-Allard-Lafarge (JCAL) model, a pivotal framework in acoustics for analyzing sound absorption in fibrous materials, presents challenges in practical implementation due to its complexity. This paper introduces a refined variant of the JCAL model explicitly tailored for fibrous materials, aiming to balance accuracy and computational efficiency. The proposed model retains essential physical principles while simplifying computational intricacies, enhancing its usability for real-time applications and large-scale simulations. Through comprehensive validation against experimental data, we demonstrate the efficacy of the simplified model in accurately characterizing the sound absorption behavior of fibrous materials. This study contributes to advancing the practical applicability of the JCAL model, facilitating its broader adoption across various acoustic engineering domains. The proposed simplification approach holds promise for accelerating research and development in sound absorption materials and acoustic design methodologies within scientific and engineering communities.

Synthesis of Co3O4@C/Ti3C2Tx MXene composites for enhanced electromagnetic wave absorption

Due to the harmful effects of electromagnetic pollution on human bodies and electronic devices, efficient microwave absorbing materials have garnered significant attention. In this paper, highly efficient microwave-absorbing Co3O4@C/Ti3C2Tx composites were synthesized by a combination of hydrothermal and electrostatic self-assembly methods. Benefiting from the synergistic effects of the multiple reflections in the Co3O4@C core-shell structure and the high conductivity coupled with the large surface area of Ti3C2Tx, the composite material, with a mass ratio of 1: 2, exhibits remarkable wave absorption capabilities, achieving a minimum reflection loss (RL) of −35.2 dB at a thickness of 4.5 mm and an effective absorption bandwidth (EAB) of 7.4 GHz within the 2–18 GHz frequency range. It is noteworthy that the smaller the RL value, the higher the material's absorption performance, and the wider the frequency range covered by the EAB, the better the overall absorption effect. Specifically, an RL value below −10 dB corresponds to an absorption rate of 90 %, which further enhances to 99 % for RL values below −20 dB. The outstanding electromagnetic wave absorption performance of the Co3O4@C/Ti3C2Tx composites can be primarily attributed to the synergy between the multiple reflective absorptions offered by the core-shell structure and the exceptional conductivity and high specific surface area inherent in the MXene material. These findings underscore the promising potential of Co3O4@C/Ti3C2Tx composites for electromagnetic absorption applications and offer a novel perspective for the design of MXene-based magnetic absorption materials.

Designing Tb-doped Mn-Ni-Cu ferrite meta-absorbers for a broad frequency range: Magnetodielectric, physical, reflection loss, and absorptivity characteristics

Developing meta-absorbers with exceptional EM wave absorption, shielding capacity, and superior dissipation performance remains worthwhile in the gigahertz (GHz) range. Electromagnetic pollution has a detrimental impact on the health of living organisms due to the emergence of high-frequency waves from communication devices. The challenges were addressed by preparing, designing, and simulating ferrite-based meta-absorbers. The nanoferrites of Tb-doped Mn-Ni-Cu (Mn0.2Ni0.3Cu0.5TbxFe2-xO4) with different levels of Tb (x = 0.00, 0.025, 0.05, 0.075) were prepared utilizing the sol-gel auto combustion technique. The phase, structural, elastic, and magnetic features of the Tb-doped Mn-Ni-Cu ferrites were examined using XRD, FESEM, FTIR, and VSM techniques, respectively. The MAUD software was utilized to obtain refinement and precise structural characteristics. The force constant, phase, and elastic properties were also assessed. The magnetization and coercivity exhibited a reduction. An assessment was conducted on the performance of field switching and high-frequency response. At high frequencies, the dielectric characteristics, such as complex permeability and permittivity, exhibit greater values, while losses diminish. At a frequency of 4.6 GHz, a reflection loss (RL) of −54.21 dB was measured for x = 0.05, whereas a reflection loss of −54.03 dB was measured for x = 0.075. The meta-absorbers of Tb-doped Mn-Ni-Cu ferrites were designed and simulated. The absorptivity of the Tb-doped Mn-Ni-Cu ferrite substrate material is illustrated. The meta-absorber exhibited three distinct absorption peaks at frequencies of 1.5, 2.5, and 4.5–6 GHz, respectively. The absorptivity of the material likewise rises with an increase in the incidence angle; the material's absorptivity also increases. The TM mode exhibited the highest values at an angle of 60 degrees, while the TE mode displayed the highest values at an angle of 0 degrees. Tb-doped Mn-Ni-Cu ferrites are effective for electromagnetic interference (EMI), multilayer ceramic integrated circuits (MLCIs), shielding, and absorbing high-frequency signals in 5 G applications.

Multi-objective optimization of micro crystalline cellulose and montmorillonite filled poly lactic acid bio–composite and its characterizations

In this research study, the synthesis of poly lactic acid (PLA) based bio composite material factors contributions were investigated through the Taguchi-based grey relational analysis (GRA) technique. Effects of micro crystalline cellulose (MCC) and montmorillonite (MTT) nano clay filler, sorbitol (S) plasticizer, and temperature (T) operating factor on the PLA matrix through melt-mixing preparation method. The tensile strength (TS), Young modulus (YM), flexural strength (FS), flexural modulus (FM), hardness, impact strength (IS), water absorption (WA), and density properties of bio composite material were investigated for each experimental setup (orthogonal array, L16). Additionally, neat PLA and optimal sample structural, thermal, and morphological properties were examined through Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (X-RD), thermal gravimetry analysis/differential thermal gravimetry (TGA/DTG), and DSC and SEM analyses. The obtained result for optimal mechanical and physical properties of MCC/MTT/S/PLA bio composite was MCC at level 3 (6%), MTT at level 4 (9%), S at level 2 (10%), and T at level 4 (175 °C). Analysis of variance (ANOVA) shows that MTT has the greatest significant effect on mechanical and physical properties of MCC/MTT/S/PLA bio composite followed by MCC, T, and S. The confirmation test indicates that the improvement of weighted grey relational grade (GRG) from 0.7896 to 0.846 and the FTIR, XRD, thermal gravimetry/differential scanning calorimetry (TG/DSC), and scanning electron microscopy (SEM) results indicates that the good interaction between PLA and fillers, improvement of thermal and morphological properties of optimal (6MCC/9MTT/10S/175 °C) bio composite samples. Therefore, the multi-response characteristics of MCC/MTT/S/PLA bio composite can be highly improved by this technique.

Efficient photocatalytic CO2 and Cr(VI) reduction on carbon quantum dots/carbon nitride heterojunctions

Carbon quantum dots (CQDs), known for their exceptional optical properties, hold the potential to enhance light absorption, charges separation and transfer in semiconductor materials. However, using cheap medicinal materials as precursors in the field of photocatalysis to obtain CQDs has seldom concerned. In this study, we utilized biomass-derived CQDs from carbon-rich licorice powder to improve photocatalytic CO2 and Cr(VI) reduction in polymer carbon nitride (PCN). The CQDs/g-C3N4 heterojunctions were synthesized via a hydrothermal method, and the successful fabrication and integration of CQDs on g-C3N4 surfaces were confirmed through detailed characterization. The optimal sample with a licorice powder to PCN mass ratio of 0.05:1 ((50CQDs/CN) demonstrates a tripling in CO2 conversion efficiency under simulated sunlight compared to the reference PCN. Under visible light irradiation, the 50CQDs/CN also performs superior photocatalytic Cr (VI) removal efficiency, which is 2.48 times of that of the reference PCN. This significant boost is attributable to the successful construction of the CQDs/CN heterojunction and the abundance of functional groups on the CQDs surface, which provide more active sites, improve light absorption and increase charges migration rates. The stability of these new photocatalysts was confirmed through repeated photocatalytic cycles, indicating their potential for practical applications. Mechanistic studies reveal insights into the enhanced photocatalytic pathways and intermediate conversion processes. Our findings present a novel, efficient and sustainable route to fabricate g-C3N4-based photocatalysts, offering a promising strategy for further mitigate the greenhouse gas crisis and environmental pollution.