Future Materials Research Articles

The effects of physiologically relevant environmental conditions on the mechanical properties of 3D-printed biopolymer nanocomposites

The demand for synthetic bone graft biomaterials has grown in recent years to alleviate the dependence on natural bone grafts and metal prostheses which are associated with significant practical and clinical issues. Biopolymer nanocomposites are a class of materials that display strong potential for these synthetic materials, especially when processed using additive manufacturing technologies. Novel nanocomposite biomaterials capable of masked stereolithography printing have been developed from functionalized plant-based monomers and hydroxyapatite (HA) with mechanical properties exceeding those of commercial bone cements. However, these biomaterials have not been evaluated under relevant physiological conditions. The effects of temperature (room temperature vs. 37 °C) and water absorption on the physical, surface, and mechanical properties of HA-containing biopolymer nanocomposites were investigated. Exposure to relevant conditions led to substantial impacts on material performance, such as significantly reduced mechanical strength and stiffness. For instance, a composite containing 10 vol% HA and functionalized monomers had 26 and 21% reductions in compressive yield strength and elastic modulus, respectively. After 14 days incubation in phosphate buffered saline, the same composition displayed a 62% decrease in compressive yield strength to 28 MPa. This manuscript demonstrates the relevance and importance of evaluating biomaterials under appropriate physiological conditions throughout their development and provides direction for future material development of HA-containing biopolymer nanocomposites.

Dynamic material flow analysis of construction materials in Saudi Arabia: Strategies for sustainability of residential buildings

Globally, the expansion of building infrastructure has serious environmental implications due to emissions from cement and steel. The construction industry uses the vast majority of cement and steel produced globally and locally. Consequently, this paper proposes a model to estimate and mitigate future material flow emissions into residential buildings in Saudi Arabia. First, a dynamic material flow model is used to quantify material flows and stock in residential buildings. The evolution of Saudi housing stock and related steel and cement are simulated from 1950 to 2100. Second, various strategies such as material efficiency improvement, lifetime extension, and reducing production emissions are simulated to reduce emissions caused by cement and steel. The findings indicate that implementing substantial material efficiency improvements can result in 33 %–46 % reductions of cumulative steel and cement emissions from 2023 to 2100, respectively. Furthermore, improving material efficiency measures could result in over 80 % reductions in emissions for steel over the same period. Reducing the ratio of clinker to supplementary cementitious materials in cement to 75 % could reduce cumulative cement emissions by 129 million tCO2e (17 %). Adoption of high material efficiency practices in cement use, low clinker cement, and waste as fuel can reduce emissions by 70 %. The findings of this study contribute to a better understanding of future emissions from building materials used in residential buildings, as well as the impact of emission mitigation strategies on future emissions, which will help decision-makers and researchers develop policies and research.

Conveyor CVD to high-quality and productivity of large-area graphene and its potentiality

The mass production of high-quality graphene is required for industrial application as a future electronic material. However, the chemical vapor deposition (CVD) systems previously studied for graphene production face bottlenecks in terms of quality, speed, and reproducibility. Herein, we report a novel conveyor CVD system that enables rapid graphene synthesis using liquid precursors. Pristine and nitrogen-doped graphene samples of a size comparable to a smartphone (15 cm × 5 cm) are successfully synthesized at temperatures of 900, 950, and 1000 °C using butane and pyridine, respectively. Raman spectroscopy allows optimization of the rapid-synthesis conditions to achieve uniformity and high quality. By conducting compositional analysis via X-ray photoelectron spectroscopy as well as electrical characterization, it is confirmed that graphene synthesis and nitrogen doping degree can be adjusted by varying the synthesis conditions. Testing the corresponding graphene samples as gas-sensor channels for NH3 and NO2 and evaluating their response characteristics show that the gas sensors exhibit polar characteristics in terms of gas adsorption and desorption depending on the type of gas, with contrasting characteristics depending on the presence or absence of nitrogen doping; nitrogen-doped graphene exhibits superior gas-sensing sensitivity and response speed compared with pristine graphene.

Dynamic-to-static switch of hydrogen bonds induces a metal-insulator transition in an organic-inorganic superlattice.

Hydrogen bonds profoundly influence the fundamental chemical, physical and biological properties of molecules and materials. Owing to their relatively weaker interactions compared to other chemical bonds, hydrogen bonds alone are generally insufficient to induce substantial changes in electrical properties, thus imposing severe constraints on their applications in related devices. Here we report a metal-insulator transition controlled by hydrogen bonds for an organic-inorganic (1,3-diaminopropane)0.5SnSe2 superlattice that exhibits a colossal on-off ratio of 107 in electrical resistivity. The key to inducing the transition is a change in the amino group's hydrogen-bonding structure from dynamic to static. In the dynamic state, thermally activated free rotation continuously breaks and forms transient hydrogen bonds with adjacent Se anions. In the static state, the amino group forms three fixed-angle positions, each separated by 120°. Our findings contribute to the understanding of electrical phenomena in organic-inorganic hybrid materials and may be used for the design of future molecule-based electronic materials.

Ultrathin and highly flexible layered silver nanowires/carboxymethyl cellulose nanofiber nanocomposite films for electromagnetic interference shielding

Lightweight, flexible, efficient and easy-to-manufacture electromagnetic interference (EMI) shielding materials are in urgent demand in the communications industry, artificial intelligence and wearable electronics. Based on the large size difference between one-dimensional carboxymethyl cellulose nanofibers (CMC) and large-diameter silver nanowires (AgNWs), layered AgNWs/CMC nanocomposite films with large effective thickness, and high conductivity were first prepared by a simple one-step vacuum filtration self-assembly technique. The unique layered structure of the AgNWs/CMC nanocomposite film significantly enhances the conductive pathways within the film, endowing it excellent EMI shielding performance. The results show that the conductivity of the ultra-thin film with a thickness of 20 μm is 3.72 × 106 S/m, and the EMI SE in the X-band is 87.7 dB, which can effectively shield electromagnetic signals in mobile communications. Furthermore, the AgNWs/CMCs nanocomposite films exhibit excellent thermal management performance, which can be heated to 100–180 °C within 10 s at a low voltage of 1.5 V. In particular, this nanocomposite film with a new layered structure provides a noval preparation idea for future EMI shielding materials and wearable heating devices.

The Development of Polylactide Nanocomposites: A Review

Polylactide materials present a promising alternative to petroleum-based polymers due to their sustainability and biodegradability, although they have certain limitations in physical and mechanical properties for specific applications. The incorporation of nanoparticles, such as layered silicate (clay), carbon nanotubes, metal or metal oxide, cellulose nanowhiskers, can address these limitations by enhancing the thermal, mechanicals, barriers, and some other properties of polylactide. However, the distinct characteristics of these nanoparticles can affect the compatibility and processing of polylactide blends. In the polylactide nanocomposites, well-dispersed nanoparticles within the polylactide matrix result in excellent mechanical and thermal properties of the materials. Surface modification is required to improve compatibility and the crystallization process in the blended materials. This article reviews the development of polylactide nanocomposites and their applications. It discusses the general aspect of polylactides and nanomaterials as nanofillers, followed by the discussion of the processing and characterization of polylactide nanocomposites, including their applications. The final section summarizes and discusses the future challenges of polylactide nanocomposites concerning the future material’s requirements and economic considerations. As eco-friendly materials, polylactide nanocomposites offer significant potential to replace petroleum-based polymers.

Chem4Energy: a consortium of the Royal Society Africa Capacity-Building Initiative.

The Africa Capacity-Building Initiative is a Royal Society programme funded by the former UK Department for International Development to develop collaborative research between scientists in sub-Saharan Africa and the UK. Initially, four institutions were involved in the Chem4Energy consortium: Cardiff University in the UK and three African partners, the Kwame Nkrumah University of Science and Technology, Ghana, the University of Namibia and the University of Botswana, soon also including the Botswana International University of Science and Technology. The Chem4Energy research programme focused on 'New materials for a sustainable energy future: linking computation with experiment', aiming to deploy the synergy between state-of-the-art computational and experimental techniques to design and optimize new catalysts and semiconductor materials for renewable energy applications, based on materials that are abundant and readily available in African countries. The Chem4Energy consortium has achieved ambitious research goals, graduated seven PhD students and delivered a high-quality cross-disciplinary training programme in materials science and simulation techniques relevant to renewable energy applications. Since 2021, the extended consortium, including North-West University and the Centre for High-Performance Computing in South Africa, has remained active through an annual Chem4Energy conference series, with the sixth meeting taking place in Namibia in April 2025.

(Invited) Plasma Designing of Hybrid 2D Graphene: A Green Approach for Future Energy Materials

The global research interest in two-dimensional (2D) materials and their derivatives has increased significantly, driven by the requirements of application-oriented materials for different sectors, including energy storage. Among the various classes of material groups, 2D layered materials have emerged as a critical research area due to their high aspect ratio, open edge boundaries, high surface-to-volume ratios, and mechanical and electrical properties. Graphene is a widely researched 2D class material with an atomically thin structure, excellent electronic properties, very high intrinsic mobility and exceptional thermal and electrical conductivity1. Even though the research on the electronic properties of graphene is explored very well and in a matured state, the studies on non-electronic properties are still in the budding phase. One of the significant obstacles to extending the studies of graphene to different fields is the cost-effective and environmentally friendly large-scale synthesis and processing of high-quality graphene. Thus, a cutting-edge approach for probing graphene structures at the atomic scale is required to produce high-quality graphene for next-generation applications. As an alternative progressive technique, plasma-enabled methods have emerged as safe and green approaches to tailor different graphene structures at the nanoscale. During graphene production, plasma assembles the nanostructures from gaseous into a solid form or converts solid precursor to graphitic form 2,3. Besides, plasma techniques open up the possibility of tailoring the properties by crafting heteroatoms to the graphene lattice, which is beneficial for energy storage applications4. Therefore, this paper introduces the advantages of plasma-enabled techniques in designing graphene-based materials with different morphologies and orientations and tailoring them at the nanoscale using heteroatoms. Such plasma-assisted techniques ensure the high structural quality of graphene and controllability in the hybrid morphologies, making them frontrunner energy storage applications. Plasma also offers the production of graphene directly on any substrate surface, gives a new direction to designing binder-free electrodes for energy-related applications, and could be used as a competitive alternative approach to the widely known wet chemical procedures to design advanced graphene electrode materials for next-generation energy storage devices.Reference Geim, A. K. Graphene: Status and prospects. Science (1979) 324, 1530–1534 (2009).Dias, A. et al. N-Graphene-Metal-Oxide(Sulfide) hybrid Nanostructures: Single-step plasma-enabled approach for energy storage applications. Chemical Engineering Journal 430, 133153 (2022).Jagodar, A. et al. Growth of graphene nanowalls in low-temperature plasma: Experimental insight in initial growth and importance of wall conditioning. Appl Surf Sci 643, 158716 (2024).Santhosh, N.M. et al. N-Graphene Nanowalls via Plasma Nitrogen Incorporation and Substitution: The Experimental Evidence. Nanomicro Lett 12, 53 (2020).

Novel Ru-Based PEM Electrolysis Catalyst – Development from the Nano- to the Industrial-Scale

For the de-fossilization of sectors like chemicals, steel, and transportation, green H2 generated via water electrolysis provides a path towards net-zero. The broad use of H2 across hard-to-abate sectors confirms the urgent need for green hydrogen at scale.Within water electrolysis, there are several competing technologies: the so-called solid oxide electrolysis cell (SOEC), alkaline water electrolysis (AEL) and polymer electrolyte membrane electrolysis (PEM EL). Here, the latter shows significant benefits, such as high current density operation (> 2 A/cm2) and thus a smaller footprint, highly dynamic operation mode, high gas purity, and generation of pressurized hydrogen. However, at present, PEM EL requires precious metal catalysts; in particular, the O2 evolution on the anode currently relies on iridium, a metal which is rather scarce and expensive [1].To meet the demand of iridium with respect to the announced increase in electrolyzer capacities in the multi-GW range, material innovation to reduce the use of this precious metal must be implemented. Successful catalyst and electrode developments have already been demonstrated in the BMBF funded project Kopernikus P2X, whereby loadings of approx. 0.3 mg/cm2 (< 0.1 g/kW1) have been achieved without any significant losses in activity over time [2, 3].Here, we present a material innovation in the form of Ru-based electrocatalysts with a significantly reduced Ir content. This ruthenium-iridium oxide can be adjusted in a wide range of Ir content down to less than 15 wt.% (Ir). Consequently, iridium-based electrode loadings of less than 0.1 mg/cm2 and mass activities of about 3,500 A/g are feasible. Moreover, in accelerated degradation tests those mixed-oxides have demonstrated the often-missing stability by showing low degradation rates, similar to that of pure IrO2, in up to 30,000 potential-induced stress cycles.This achievement stems from a remarkable screening approach that combines synthesis, characterization and testing at the nanoscale at Mattiq, and on industrial scale in the multi-gram range at Heraeus Precious Metals GmbH & Co. KG. Remarkably the alignment of degradation testing on both scales showcases the power of the applied method, providing a blueprint for high throughput screening for future material developments, both within water electrolysis and beyond.

Tuning Proton Conduction by Staggered Arrays of Polar Preyssler-Type Oxoclusters.

Polyoxometalates (POMs), anionic nanosized oxoclusters that can be considered as fragments of metal oxides, have been extensively studied for their diverse composition and structure, showing promise in various fields such as catalysis and electronics. Proton conduction, relevant to catalysis and electronics, has attracted interest in materials chemistry, and POM anions are advantageous in terms of their proton carrier density and mobility. Recently, polar POMs have attracted attention for their unique ferroelectric behaviors, yet they have been little studied with regard to proton conduction, as their polarity has generally been believed to have a negative impact. Here, we propose that polar POMs can be used to align polar proton carriers, such as H2O and polymers, to construct efficient proton-conducting pathways. In this study, we present ionic crystals composed of polar Preyssler-type POMs ([Xn+(H2O)P5W30O110](15-n)-, Xn+ = Ca2+, Eu3+) and K+ exhibiting ultrahigh proton conductivity surpassing 10-2 S cm-1, which is required for practical applications. In contrast, ionic crystals with nonpolar Preyssler-type POMs show an order of magnitude lower proton conductivity. Structural and spectroscopic studies combined with theoretical calculations reveal that proton carriers align with the aid of staggered arrays of polar POMs, forming a hydrogen-bonding network favorable for proton conduction. This study integrates molecular chemistry by the design of POMs and solid-state chemistry by exploring long-range proton conduction mechanisms, offering novel insights for future materials design.

ANALISIS KEMAMPUAN PEMECAHAN MASALAH MATEMATIKA MATERI BANGUN DATAR SISWA KELAS V SEKOLAH DASAR

The purpose of this study is to characterize and understand the mathematical problem-solving skills of fifth-grade students at SDN 1 Tanjung Sari, particularly with regard to narrative problems with flat forms. This study employs a qualitative descriptive methodology that focuses on close observation and in-depth examination of the research participants, who are SDN 1 Tanjung Sari fifth-grade pupils. Two primary methods were used in this study to gather data: assessments of students' mathematical problem-solving skills and interviews. The Miles and Huberman Model, which has three primary stages data reduction, data presentation, and conclusion drawing was used to conduct the data analysis. The technique of eliminating extraneous or useless data is known as data reduction. Data presentation is the process of arranging and displaying information in a way that is simple to understand. Drawing conclusions from study results entails analyzing data and drawing judgments. The study's findings indicate that pupils' average proficiency in solving mathematical problems involving flat shapes is 75.78, falling within the middle range. This indicates that although there is still need for development, pupils' grasp of the notion of flat forms is adequate. The study indicated that, when considering learning interest, students' average mathematical problem-solving skill was 87.22 for high learning interest students, 74.85 for moderate learning interest students, and 57.80 for low learning interest students. This demonstrates that students' aptitude for solving mathematical puzzles is greatly influenced by their learning interests. Overall, this study offers significant new information on how learning interests might influence students' ability to solve mathematical problems. Future instructional materials for more efficient learning can be developed using these findings as a foundation

Reaction of a Molten Cr-Si-Base Alloy with Ceramics and a High Entropy Oxide

Due to their higher thermal and chemical stability than other high-temperature materials, chromium-silicon-base (Cr-Si-base) alloys are promising materials for future gas turbines and other high-temperature applications operating under harsh conditions. To enable near-net-shape casting of Cr-Si-base alloys, a compatibility of the alloy melt with the ceramic crucibles and molds is necessary. Additionally, a metal-ceramic contact exists at the interface between thermal barrier coating (TBC) and alloy, where metallic may melts play a role in the case of coating failure and overheating. In this study, molten Cr92Si8 (in at. %) alloy is brought into contact with powders of ceramics commonly used for casting molds or crucibles (e.g. ZrSiO4, Al2O3, 3YSZ), to investigate liquid metal corrosion, interdiffusion, and stabilities. Additionally, the high entropy oxide (Sm0.2Gd0.2Dy0.2Er0.2Yb0.2)2Zr2O7 (HEO), a potential future TBC material, is investigated. Before melting using an electric arc furnace, the powders of the investigated ceramics were mixed with pulverized Cr92Si8 and pressed into alloy-ceramic pairs, to maximize the contact area between molten metal and ceramic. For microstructural investigations and phase analysis, the materials were assessed using scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The widely used mold material ZrSiO4 and the coating BN were found to decompose, while reaction products of SiO2 and CoAl2O4 with the melt were detected. Al2O3, 3YSZ, and the HEO did not show decomposition or corrosion by the melt. Al2O3, 3YSZ, and the HEO are therefore considered as promising crucible, mold, and TBC materials for Cr-Si-base alloys.

A 3D CFD-FEA co-simulation study of low thermal effusivity TBCs applied to the piston and valves of an SI engine

When applied on combustion chamber walls, thermal barrier coatings (TBCs) with low thermal effusivity provide a pathway for reducing heat transfer and improving SI engine efficiency. A 3D CFD-1D FEA co-simulation routine was employed to study the effects of a proprietary TBC on SI engine performance under different permutations of coating the piston, exhaust valves, and intake valves. Marginal reductions (&lt;0.1% points) in total heat transfer and improvements to efficiency were observed when all the three components were coated with the proprietary TBC. Two hypothetical TBC materials with ideally low thermal effusivities were formed by modifying the current material properties and their effect on engine performance was similarly studied at three engine loads at the same engine speed. It was found that coating all the three components with the lowest thermal effusivity TBC offers the largest improvements (∼0.5% points) in net fuel conversion efficiency accompanied by largest reduction (∼1.1% points) in total heat transfer, thus establishing expectations from future TBC materials.

Multiple Chirality Switching of a Dye‐Grafted Helical Polymer Film Driven by Acid &amp; Base

AbstractA stimuli‐responsive multiple chirality switching material, which can regulate opposed chiral absorption characteristics, has great application value in the fields of optical modulation, information storage and encryption, etc. However, due to the rareness of effective functional systems and the complexity of material structures, developing this type of material remains an insurmountable challenge. Herein, a smart polymer film with multiple chirality inversion properties was fabricated efficiently based on a newly‐designed acid &amp; base‐sensitive dye‐grafted helical polymer. Benefited from the cooperative effects of various weak interactions (hydrogen bonds, electrostatic interaction, etc.) under the aggregated state, this polymer film exhibited a promising acid &amp; base‐driven multiple chirality inversion property containing record switchable chiral states (up to five while the solution showed three‐state switching) and good reversibility. The creative exploration of such a multiple chirality switching material can not only promote the application progress of current chiroptical regulation technology, but also provide a significant guidance for the design and synthesis of future smart chiroptical switching materials and devices.

Multiple Chirality Switching of a Dye-Grafted Helical Polymer Film Driven by Acid & Base.

A stimuli-responsive multiple chirality switching material, which can regulate opposed chiral absorption characteristics, has great application value in the fields of optical modulation, information storage and encryption, etc. However, due to the rareness of effective functional systems and the complexity of material structures, developing this type of material remains an insurmountable challenge. Herein, a smart polymer film with multiple chirality inversion properties was fabricated efficiently based on a newly-designed acid & base-sensitive dye-grafted helical polymer. Benefited from the cooperative effects of various weak interactions (hydrogen bonds, electrostatic interaction, etc.) under the aggregated state, this polymer film exhibited a promising acid & base-driven multiple chirality inversion property containing record switchable chiral states (up to five while the solution showed three-state switching) and good reversibility. The creative exploration of such a multiple chirality switching material can not only promote the application progress of current chiroptical regulation technology, but also provide a significant guidance for the design and synthesis of future smart chiroptical switching materials and devices.

Janus nanocellulose membrane by nitrogen plasma: Hydrophilicity to hydrophobicity selective switch

Cellulose nanofibrils are one of the keystone materials for sustainable future, yet their poor water repellency hinders their push into industrial applications. Due to complexity and poor economical outcome and/or processing toxicity of the existing hydrophobization methods, nanocellulose loses against its antagonist plastic in medical and food industries. Herein, we demonstrate for the first time the “one-side selective water-repellency activation” in nanocellulose membranes by the means of mild N2-plasma treatment, exhibiting lowest wettability after 20 s of treatment. Hydrophobicity and accompanying Janus character were justified by the topological, chemical and structural reorganizations in cellulose nanofibrils. The findings suggest that the mechanism behind the hydrophilic/hydrophobic change primarily relies on the interplay between OH removal and appearance of SiCH3, originating from the polysiloxanes-based substrate, as well as complementary CNH2 groups formation. First-principles calculations show that NH2 groups moderately increase hydrophobicity, while various SiCH3 substitutions wholly change the character of the surface to repel water. Using nitrogen is shown to be crucial, as N(H)Si(CH3)3 groups induce greater hydrophobicity than simple OSi(CH3)3. Finally, the obtained materials absorb water on the hydrophilic side, while remaining hydrophobic on the other, exhibit high tensile strength, and protection against UV light, demonstrating applicability over wide range of applications.

Advances in Filament Structure of 3D Bioprinted Biodegradable Bone Repair Scaffolds.

Conventional bone repair scaffolds can no longer meet the high standards and requirements of clinical applications in terms of preparation process and service performance. Studies have shown that the diversity of filament structures of implantable scaffolds is closely related to their overall properties (mechanical properties, degradation properties, and biological properties). To better elucidate the characteristics and advantages of different filament structures, this paper retrieves and summarizes the state of the art in the filament structure of the three-dimensional (3D) bioprinted biodegradable bone repair scaffolds, mainly including single-layer structure, double-layer structure, hollow structure, core-shell structure and bionic structures. The eximious performance of the novel scaffolds was discussed from different aspects (material composition, ink configuration, printing parameters, etc.). Besides, the additional functions of the current bone repair scaffold, such as chondrogenesis, angiogenesis, anti-bacteria, and anti-tumor, were also concluded. Finally, the paper prospects the future material selection, structural design, functional development, and performance optimization of bone repair scaffolds.

Unraveling the origin of the high reversibility in entropy-stabilized rocksalt-type (Mg0.2Co0.2Mn0.2Ni0.2Zn0.2)O anodes for lithium-ion storage

Entropy-stabilized rocksalt-type oxides, composed of multiple components, are increasingly recognized as highly promising materials for energy storage applications. In this study, a novel anode material, (Mg0.2Co0.2Mn0.2Ni0.2Zn0.2)O, demonstrates exceptional reversible specific capacity of 773.4 mAh g−1 even after 200 cycles at 0.1 A g−1. Density functional theory (DFT) analysis reveals superior electrical conductivity of (Mg0.2Co0.2Mn0.2Ni0.2Zn0.2)O compared to individual oxides like CoO, which has the potential to enhance electronic transfer to improve electrochemical performance. In situ transmission electron microscopy (TEM) observations confirm the reversible crystal structure of rocksalt-type (Mg0.2Co0.2Mn0.2Ni0.2Zn0.2)O anodes, with only ∼36.8 % volume expansion in four cycles. This investigation offers insights into the (de)lithiation process at a microscopic scale, shedding light on the origins of high reversibility and guiding the design of future high-entropy materials. Entropy-stabilized rocksalt-type (Mg0.2Co0.2Mn0.2Ni0.2Zn0.2)O oxides exhibit excellent properties, positioning them as promising candidates for lithium-ion batteries (LIBs) anode materials.

Biogenic Carbon Quantum Dots: Synthesis and Applications.

The new class of nanomaterials termed carbon dots: a quasi-spherical nanoparticle having a size less than 10 nm, possesses some unique characteristics like good aqueous solubility, colloidal stability, resistance to photobleaching, and fluorescence tunability, resulting in the unfolding of their various properties and their usage in different applications. Materials that are naturally derived or produced by living organisms are termed 'biogenic'. Over the past few years, there has been a gradual increase in the use of naturally derived materials in synthesizing carbon dots. Green precursors or biogenic materials are of low cost, readily available, renewable, and environmentally benign. Most importantly, they provide essential benefits not found in synthesized carbon dots. This review focuses on the use of biogenic materials for the synthesis of biogenic carbon dots developed in the past five years. It also briefly explains different synthetic protocols used, along with some significant findings. Thereafter, an overview of the use of biogenic carbon dots (BCDs) in different applications like chemo and biosensors, drug delivery, bioimaging, catalysis and energy applications, etc., is discussed. Thus biogenic carbon dots are future sustainable materials that are now fast replacing conventional carbon quantum prepared from other sources.

Recurrently gellable and thermochromic inorganic hydrogel thermogalvanic cells.

Thermogalvanic cells (TGCs) draw great attention in the field of heat to electricity conversion, but TGCs were only in the form of liquid or organic gel. Here, we report an all-inorganic hydrogel TGC via simply mixing and stirring two inorganic salt solutions. Benefiting from the hydrogen bonds resultant framework and endogenous Fe2+/3+ redox couple, the TGC can recurrently pulverize-gel with completely holding its initial thermogalvanic performances after even 60 cycles. As the temperature and pH coregulating Fe3+ concentration and reversible transformation between Fe3+ and Fe(OH)3, we boost thermopower and realize thermochromism. This work provides a different perspective for TGCs and offers an avenue for future hydrogel materials research.