Functional Carbon from Nature: Biomass-Derived Carbon Materials and the Recent Progress of Their Applications

Using tannin as a biological curing agent to design fully bio-based epoxidized natural rubber/polylactic thermoplastic vulcanizates with mechanical robustness and multi-stimuli-responsive shape memory properties

To effectively mitigate carbon emissions and promote sustainability in the polymer field, biological macromolecules have emerged as a prominent strategy for fabricating functional materials. Herein, tannin (TA) was used as a biological curing agent to design fully bio-based polylactic/epoxidized natural rubber thermoplastic vulcanizates (PLA/ENR TPVs) with mechanical robustness and multi-stimuli-responsive shape memory properties. A dual cross-linking network, comprising both covalent bonds and hydrogen bonds, was successfully constructed in the ENR phase. A special co-continuous morphology was concomitantly constructed in the TPVs, which promoted effective stress transfer between the PLA and ENR phases, endowing the TPVs with balanced stiffness-toughness and shape memory properties. Moreover, the photothermal effect of TA also made it respond to near-infrared light and sunlight, which achieved the non-contact multistage shape memory performance, revealing the significant potential of the TPVs in the field of actuators.

Biochar Meets Single-Atom: A Catalyst for Efficient Utilization in Environmental Protection Applications and Energy Conversion

Single-atom catalysts (SACs), combining the advantages of multiphase and homogeneous catalysis, have been increasingly investigated in various catalytic applications. Carbon-based SACs have attracted much attention due to their large specific surface area, high porosity, particular electronic structure, and excellent stability. As a cheap and readily available carbon material, biochar has begun to be used as an alternative to carbon nanotubes, graphene, and other such expensive carbon matrices to prepare SACs. However, a review of biochar-based SACs for environmental pollutant removal and energy conversion and storage is lacking. This review focuses on strategies for synthesizing biochar-based SACs, such as pre-treatment of organisms with metal salts, insertion of metal elements into biochar, or pyrolysis of metal-rich biomass, which are more simplistic ways of synthesizing SACs. Meanwhile, this paper attempts to 1) demonstrate their applications in environmental remediation based on advanced oxidation technology and energy conversion and storage based on electrocatalysis; 2) reveal the catalytic oxidation mechanism in different catalytic systems; 3) discuss the stability of biochar-based SACs; and 4) present the future developments and challenges regarding biochar-based SACs.

Biowaste-Derived Triboelectric Nanogenerators for Emerging Bioelectronics

Triboelectric nanogenerators (TENGs) combine contact electrification and electrostatic induction effects to convert waste mechanical energy into electrical energy. As conventional devices contribute to electronic waste, TENGs based on ecofriendly and biocompatible materials have been developed for various energy applications. Owing to the abundance, accessibility, low cost, and biodegradability of biowaste (BW), recycling these materials has gained considerable attention as a green approach for fabricating TENGs. This review provides a detailed overview of BW materials, processing techniques for BW-based TENGs (BW-TENGs), and potential applications of BW-TENGs in emerging bioelectronics. In particular, recent progress in material design, fabrication methods, and biomechanical and environmental energy-harvesting performance is discussed. This review is aimed at promoting the continued development of BW-TENGs and their adoption for sustainable energy-harvesting applications in the field of bioelectronics.

Efficient removal of nanoplastics by iron-modified biochar: Understanding the removal mechanisms

Tiny plastic particles, particularly nanoplastics, are becoming major threats to aquatic and biotic life owing to their unique physico-chemical characteristics. Thus, in the present work, biochar (BC) was fabricated using "Ulva prolifera green tide" as a biowaste raw material by slow pyrolysis technique to examine its potential in removing nanoplastics from the environment. The findings depicted that nanoplastics removal efficiency by BC was V-shaped with initial pH increased from 2 to 11, and the main removal mechanism changed from adsorption to heterogeneous aggregation between nanoplastics, biochar colloids, and leached substances from BC. When the solution pH crossed the pHpzc of BC (2.3), the aggregation kinetics were well-fitted by the logistic model and displayed as an S-shaped curve with a lag period. Characterization results indicated that biochar colloids were the key enabler with a critical concentration of 72.01 mg L-1 at neutral pH. Keeping in mind the removal mechanisms and contribution of biochar colloids, iron-modified biochar (Fe-BC) was produced to enhance the overall removal efficiency. The Fe-BC demonstrated a two-phase removal process of pre-adsorption and post-aggregation, successfully realized to minimize lag time and enhance aggregation performance. The theoretical removal capacity of Fe-BC against nanoplastics could reach up to 1626.3 mg g-1, which was three-fold higher than that of BC. Further, the Fe-BC was suggested to be recycled and reused at least three times by ultrasound, followed by co-pyrolysis for green and efficient degradation of nanoplastics. Overall, the findings offer a promising approach for removing and recycling nanoplastics in the environment.

Nanocarbons-Based Trifunctional Electrocatalysts for Overall Water Splitting and Metal-Air Batteries: Metal-Free and Hybrid Electrocatalysts

Trifunctional electrocatalysts, an exciting class of materials that can simultaneously catalyze hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR), can significantly enhance the performance and economic viability of electrochemical energy storage and conversion technologies such as water-splitting electrolyzers, metal-air batteries, fuel cells and their integrated devices. Such multifunctional electrocatalysts encompass multiple active sites that can simultaneously catalyze two or more different electrochemical reactions and are feasible routes for addressing global energy and environmental challenges. This review accounts for nanocarbons-based trifunctional electrocatalysts reported for electrolyzers, metal-air batteries and integrated electrolyzer-battery systems, providing a practical perspective. Metal-free and hybrid (hybrids of nanocarbons and transition metals/compounds) trifunctional electrocatalysts are covered. Given the growing importance of green technologies, we discuss biomass-derived carbon-based trifunctional electrocatalysts separately. The collective information provided in the review could help researchers derive more effective and durable trifunctional electrocatalysts suitable for commercial use.

Noble Metal Phosphides: Robust Electrocatalysts toward Hydrogen Evolution Reaction

Facing with serious carbon emission issues, the production of green H2 from electrocatalytic hydrogen evolution reaction (HER) has received extensive research interest. Almost all kinds of noble metal phosphides (NMPs) consisting of Pt-group elements (i.e., Ru, Rh, Pd, Os, Ir and Pt) are all highly active and pH-universal electrocatalysts toward HER. In this review, the recent progress of NMP-based HER electrocatalysts is summarized. It is further take typical examples for discussing important impact factors on the HER performance of NMPs, including crystalline phase, morphology, noble metal element and doping. Moreover, the synthesis and HER application of hybrid catalysts consisting of NMPs and other materials such as transition metal phosphides, oxides, sulfides and phosphates, carbon materials and noble metals is also reviewed. Reducing the use of noble metal is the key idea for NMP-based hybrid electrocatalysts, while the expanded functionality and structure-performance relationship are also noticed in this part. At last, the potential opportunities and challenges for this kind of highly active catalyst is discussed.

Development of poly(butylene oxalate-co-furanoate) copolymers with enhanced sustainability and hydrolytic degradability

Polyoxalate, a novel intrinsically hydrolysable polyester, garners significant interest for its high cost-effectiveness and versatility. However, concerns persist regarding its durability in practical applications. This study integrates bio-based poly(butylene furanoate) (PBF), which possesses remarkable barrier performance, into the poly(butylene oxalate) (PBOx) framework to synthesize poly(butylene oxalate‑co‑furanoate) (PBOF) with tunable degradation rates. The influence of incorporating BF units on thermal, crystalline, mechanical, and barrier properties was systematically analyzed. Results demonstrated the addition of BF units dramatically improved the balance between degradation and physical properties. Laboratory degradation experiments indicated that PBOF possessed significant degradation effects. Among them, PBOF-41 (with 41 % molar furanoate) decreased in weight by 20 % in freshwater, 70 % in an enzyme solution, and 8 % in artificial seawater within 30 days. After 28 days of degradation in soil, the residual weight was reduced to 80 % of its initial weight. Theoretical calculations and experiments have clarified the enhancement of the Gibbs free energy and energy barrier of the hydrolysis reaction by the BF unit. In summary, PBOF copolyesters have excellent gas barrier performance, adjustable thermal properties, well-balanced mechanical properties, and degradability, making them highly promising for sustainable plastic products.

Deep Eutectic Solvent and Molten Salt-Assisted Construction of Wheat Straw-Derived N/O Co-Doped Porous Carbon for Flexible Zinc-Air Batteries

As a common biomass resource, wheat straw is gradually being derived as carbon materials for oxygen reduction reaction (ORR) in zinc-air batteries (ZABs). Herein, the wheat straw-derived carbon was prepared by ball milling and pyrolysis using deep eutectic solvent (DES) as the medium, which avoided the cumbersome procedures. The hydrogen bond of DES was utilized to reconstructed into a hydrogen bond network structure between DES and lignin/cellulose/hemicellulose of wheat straw. The hydrogen bond network structure was converted into N/O co-doped porous carbon (N/O-WSPC) with abundant N/O co-doped sites after high-temperature pyrolysis. Meanwhile, KHCO3 was employed to further generate hierarchical pore structures and increase the specific surface area of the N/O-WSPC. The N/O co-doped sites provided intrinsic ORR activity, while the porous structure facilitates the mass transfer effect. Therefore, the N/O-WSPC exhibited a half-wave potential of 0.87 V (vs. RHE) and a limiting current density of 5.98 mA cm-2 for ORR. The N/O-WSPC-based flexible ZAB displayed an energy density of 652.23 Wh kg-1 and a charging-discharging cycle duration for over 19 h. The DES-assisted strategy facilitates the sustainable and efficient application of wheat straw-derived carbon materials in energy storage and conversion devices.

Synthesis and application of bismuth nanoparticle-loaded longan porous carbon for simultaneous electrochemical determination of Pb(II) and cd(II) in seafoods

The discarded longan shell-derived porous carbon material (LPC) served as a scaffold for synthesizing bismuth nanoparticle-loaded longan porous carbon nanocomposite (BiNPs@LPC) via a hydrothermal method. Then BiNPs@LPC was utilized to modify screen-printed carbon electrodes (SPCE) for simultaneous detection of Pb(II) and Cd(II) by square wave anodic stripping voltammetry (SWASV). The material was thoroughly characterized by scanning electron microscopy, X-ray diffraction, Raman spectra, Brunauer-Emmett-Teller analysis, electrochemical impedance spectroscopy and cyclic voltammetry. BiNPs@LPC exhibited abundant porous structures, high surface area, and numerous active sites, which could improve significantly response sensitivity. Under optimal conditions, the peak currents of Pb(II) and Cd(II) exhibited favorable linear relationships with the concentration within a range of 0.1-150 μg L-1, with detection limits (S/N = 3) of 0.02 μg L-1 and 0.03 μg L-1, respectively. BiNPs@LPC/SPCE demonstrated remarkable selectivity, stability and repeatability. The proposed method was successfully applied for the detection of Pb(II) and Cd(II) in seafoods achieving satisfying recovery of 97.8%-108.3% and 96.7%-106.4%. These excellent test properties were coupled with convenience for batch preparation of the modified electrodes, highlighting its potential for practical applications in heavy metal detection of real samples.

Highly Graphitized Coal Tar Pitch-Derived Porous Carbon as High-Performance Lithium Storage Materials

Because of its high specific capacity and superior rate performance, porous carbon is regarded as a potential anode material for lithium-ion batteries (LIBs). However, porous carbon materials with wide pore diameter distributions suffer from low structural stability and low electrical conductivity during the application process. During this study, the calcium carbonate nanoparticle template method is used to prepare coal tar pitch-derived porous carbon (CTP-X). The coal tar pitch-derived porous carbon has a well-developed macroporous-mesoporous-microporous hierarchical porous network structure, which provides abundant active sites for Li+ storage, significantly reduces polarization and charge transfer resistance, shortens the diffusion path and promotes the rapid transport of Li+. More specifically, the CTP-2 anode shows high charge capacity (496.9 mAh g-1 at 50 mA g-1), excellent rate performance (413.6 mAh g-1 even at 500 mA g-1), and high cycling stability (capacity retention rate of about 100 % after 1,000 cycles at 2 A g-1). The clean and eco-friendly large-scale utilization of coal tar pitch will facilitate the development of high-performance anodes in the field of LIBs.

Ag-Cu2O Supported Biomass-Derived rGO for Catalyzing Suzuki-Miyaura Cross-Coupling

The search for cost-effective, efficient, and ecofriendly heterogeneous catalysts for the Suzuki-Miyaura reaction is crucial due to challenges with expensive, toxic homogeneous catalysts. This study centrally aims at crafting a pioneering green catalyst by adorning reduced graphene oxide (rGO), sourced from basil seeds (Ocimum basilicum L.), with an Ag-Cu2O composite structure. Comprehensive characterization of the Ag-Cu2O/rGO nanocomposite was conducted through FTIR, SEM, hHR-TEM, EDS, XPS, XRD, TGA, and N2 adsorption/desorption analyses. Results showed that nanosized Ag-Cu2O particles were partially integrated into rGO sheets derived from basil seeds, acting as active species for oxidative addition with aryl halides in the SMR. The catalytic efficacy of this robust nanocatalyst was assessed in Suzuki-Miyaura cross-coupling reactions, targeting the synthesis of biaryls employing various aryl halides and aryl boronic acids. The findings underscore that the Ag-Cu2O/rGO nanocatalyst manifests rapid reaction kinetics (15 min) alongside commendable yields (99%). The Ag-Cu2O/rGO demonstrates impressive recyclability, maintaining catalytic efficiency over four cycles. Utilizing it as a green substrate for metal loading highlights its potential, offering well-defined coordination sites. This approach facilitates stable heterogeneous catalyst fabrication, crucial for significant bond formations. Notable features include broad applicability, exceptional functional tolerance, scalability, and practicality. Moreover, it holds promise for automating safe processes and enabling efficient late-stage functionalization of complex molecules with moderate to high efficiency, presenting promising prospects for various applications in chemical synthesis.

Efficient Solar Steam Generation by Multiscale Photothermal Structures Derived from Cactus Stems

Solar steam generation (SSG) is a promising technique that may find applications in seawater desalination, sewage treatment, etc. The core component for SSG devices is photothermal materials, among which biomass-derived carbon materials have been extensively attempted due to their low cost, wide availability, and diversified microstructures. However, the practical performance of these materials is not satisfactory because of the multifaceted structural requirements for photothermal materials in SSG scenarios. In this work, cactus stems, which possess abundant and multiscaled pores for simultaneous sunlight gathering and water evaporation, are applied as the photothermal structure for SSG devices after mild heat treatment. Consequently, the SSG device based on the carbonized cactus stems delivers high performance (an absorption rate of 93.7% of the solar spectrum, an evaporation rate of 2.02 kg m-2 h-1, and an efficiency of 91.4% under one solar irradiation). We anticipate that the material can be a potential candidate for efficient SSG devices and may shed light on the sustainable supply of water.

Room temperature synthesis of 3D-nanocrystalline graphitic carbon from biomass-derived sugars, alcohols, and polyphenolic compounds

Nanocrystalline carbon materials exhibit promising potential for sustainable and high-performance applications in electronics, energy storage, and environmental technologies. While sugars are abundant and renewable, converting them to graphitic carbon usually requires high temperature treatment. Here, we present a groundbreaking approach for synthesizing nanocrystalline carbon from readily available sugars such as glucose, fructose, and sucrose at ambient pressure and temperature. This novel method involves electrochemical reduction on a negatively charged Ag surface coupled with intermolecular dehydration between the organic precursors. By applying relatively low potentials ranging from -1.2 to -1.6 V vs. Ag/AgCl, and with the presence of hydrogen peroxide, oxygenic carbon precursors are efficiently transformed into nanocrystalline hybrid carbon structures. The role of hydrogen peroxide is pivotal in expediting hydrogen abstraction and facilitating the formation of 3D-nanostructured carbon allotropes. Characterization results based on Raman spectroscopy, transmission electron microscopy-energy dispersive X-ray spectroscopy-selected area electron diffraction (TEM-EDX-SAED), X-ray photoelectron spectroscopy (XPS), and grazing incidence-X-ray diffraction (GI-XRD) confirm the presence of mixed nanocrystalline sp2-sp3 hybridization in the resulting carbon materials. Moreover, this method's versatility extends beyond sugars to include alcohols, polyols, and polyphenolic compounds like ethanol, glycerol, and tannic acid, broadening its potential for biomass valorization.

Acid-modified biomass-based N-doped O-rich hierarchical porous carbon as a high-performance electrode for supercapacitors

In contemporary society, the conversion and efficient utilization of waste biomass and its derivatives are of great significance. Carbonized wood (CW) is an easily accessible and cost-effective green resource, but it has limitations as an electrode material due to its low specific surface area, limited active sites and poor conductivity. Therefore, it is crucial to improve the performance of biomass-based materials by using activation, heteroatom doping and modification methods to enhance the specific surface area and active sites. In this study, we developed acid-modified urea-doped activated carbonized wood (AUACW) with a three-dimensional (3D) porous structure and porosity, achieving a high specific surface area of 1321.3 m2 g-1. In addition, the degree of graphitization (ID/IG = 1.0) provides good conductivity and a large number of active sites, which are conducive to charge transfer and ion diffusion. The increase of nitrogen and oxygen elements enhances the surface wettability of the material and provides additional pseudocapacitance. The specific capacitance of AUACW reaches 435.84 F g-1 at 0.8 A g-1 with a 93.6% capacitance retention after 10 000 cycles in a 1 M KOH electrolyte. More attractively, a symmetrical supercapacitor (SSC) based on AUACW delivers an energy density of 22.61 W h kg-1 at a power density of 533.26 W kg-1. This work demonstrates the promising potential of utilizing waste biomass to develop green and valuable carbon materials for supercapacitors.

Progress Made in Non-Metallic-Doped Materials for Electrocatalytic Reduction in Ammonia Production

The electrocatalytic production of ammonia has garnered considerable interest as a potentially sustainable technology for ammonia synthesis. Recently, non-metallic-doped materials have emerged as promising electrochemical catalysts for this purpose. This paper presents a comprehensive review of the latest research on non-metallic-doped materials for electrocatalytic ammonia production. Researchers have engineered a variety of materials, doped with non-metals such as nitrogen (N), boron (B), phosphorus (P), and sulfur (S), into different forms and structures to enhance their electrocatalytic activity and selectivity. A comparison among different non-metallic dopants reveals their distinct effects on the electrocatalytic performance for ammonia production. For instance, N-doping has shown enhanced activity owing to the introduction of nitrogen vacancies (NVs) and improved charge transfer kinetics. B-doping has demonstrated improved selectivity and stability, which is attributed to the formation of active sites and the suppression of competing reactions. P-doping has exhibited increased ammonia generation rates and Faradaic efficiencies, likely due to the modification of the electronic structure and surface properties. S-doping has shown potential for enhancing electrocatalytic performance, although further investigations are needed to elucidate the underlying mechanisms. These comparisons provide valuable insights for researchers to conduct in-depth studies focusing on specific non-metallic dopants, exploring their unique properties, and optimizing their performance for electrocatalytic ammonia production. However, we consider it a priority to provide insight into the recent progress made in non-metal-doped materials and their potential for enabling long-term and efficient electrochemical ammonia production. Additionally, this paper discusses the synthetic procedures used to produce non-metal-doped materials and highlights the advantages and disadvantages of each method. It also provides an in-depth analysis of the electrochemical performance of these materials, including their Faradaic efficiencies, ammonia yield rate, and selectivity. It examines the challenges and prospects of developing non-metallic-doped materials for electrocatalytic ammonia production and suggests future research directions.

A Portable Electrochemical Dopamine Detector Using a Fish Scale-Derived Graphitized Carbon-Modified Screen-Printed Carbon Electrode

In this paper, a highly conductive alkali-activated graphitized carbon (a-GC) was prepared using tilapia fish scales as precursors through enzymolysis, activation and pyrolytic carbonization methods. The prepared a-GC was modified on the surface of a screen-printed carbon electrode to construct a flexible portable electrochemical sensing platform, which was applied to the differential pulse voltametric detection of dopamine (DA) using a U-disk electrochemical workstation combined with a smart phone and Bluetooth. The prepared a-GC possesses good electrical conductivity, a large specific surface area and abundant active sites, which are beneficial for the electrooxidation of DA molecules and result in excellent sensitivity and high selectivity for DA analysis. Under the optimal conditions, the oxidation peak current of DA increased gradually, with its concentrations in the range from 1.0 μmol/L to 1000.0 μmol/L, with the detection limit as low as 0.25 μmol/L (3S/N). The proposed sensor was further applied to the determination of DA in human sweat samples, with satisfactory results, which provided an opportunity for developing noninvasive early diagnosis and nursing equipment.

The emergence and prospects of carbon dots with solid-state photoluminescence for light-emitting diodes

The significant features of carbon dots (CDs), such as bright and tunable photoluminescence, high thermal stability, and low toxicity, endow them with tremendous potential for application in next generation optoelectronics. Despite great progress achieved in the design of high-performance CDs so far, the practical applications in solid-state lighting and displays have been retarded by the aggregation-caused quenching (ACQ) effect ascribed to direct π-π interactions. This review provides a comprehensive overview of the recent progress made in solid-state CD emitters, including their synthesis, optical properties and applications in light-emitting diodes (LEDs). Their triplet-excited-state-involved properties, as well as their recent advances in phosphor-converted LEDs and electroluminescent LEDs, are mainly reviewed here. Finally, the prospects and challenges of solid-state CD-based LEDs are discussed with an eye on future development. We hope that this review will provide critical insights to inspire new exciting discoveries on solid-state CDs from both fundamental and practical standpoints so that the realization of their potential in optoelectronic areas can be facilitated.

Energy storage and key derives of octadecane thermal stability during phase change assembly with animal manure-derived biochar

The design of eco-friendly and renewable energy infrastructure is highly desirable to advance the global energy landscape. Phase-change materials (PCMs) are used to mitigate intermittency issues and reversibly store high densities of thermal energy in the form of heat during the phase transition process and provide ample potential for the advancement of renewable energy infrastructure. However, the leakage and low thermal stability of pristine PCMs along with the complicated synthesis strategies and environmental issues of the supporting materials cause significant drawbacks, thereby requiring a sustainable confining agent. In this study, a green phase change composite was developed using biowaste-derived biochar and octadecane via a vacuum impregnation strategy. The structural, morphological, thermal, and shape stabilities, as well as the chemical compatibilities of both the composite components and the octadecane-biochar composite, were investigated. The supporting biochar provides sufficient physical and thermal support besides high encapsulating capacity due to high specific surface area (135.2 m2 g-1) and predominant mesoporous proportion (86%). The results displayed that the composite material revealed a high leakage-proof capability (above the melting point of pure octadecane) with a low leakage rate (<12.5%) for a long heating time, excellent thermal stability, and high latent heat retention (89.5%) after 1000 heating-cooling cycles. The fabricated composite attained satisfactory phase change enthalpy storage, which was 130% and 168.9% higher than that of rice-husk-paraffin and garlic peel-derived carbon-paraffin, respectively, indicating promising thermal management performance. This study opens avenues for the development of green composite materials and renewable energy storage and conversion, which will play a significant role in various sectors such as building energy-saving and heat recovery systems.

Biomass-derived carbon materials for vanadium redox flow battery: From structure to property

Biomass-derived carbon (BDC) materials are suitable as electrode or catalyst materials for vanadium redox flow battery (VRFB), owing to the characteristics of vast material sources, environmental friendliness, and multifarious structures. A timely and comprehensive review of the structure and property significantly facilitates the development of BDC materials. Here, the paper starts with the preparation of biomass materials, including carbonization and activation. It is designed to summarize the lastest developments in BDC materials of VRFB in four different structural dimensions from zero dimension (0D) to three dimension (3D). Every dimension begins with meticulously selected examples to introduce the structural characteristics of materials and then illustrates the improved performance of the VRFB due to the structure. Simultaneously, challenges, solutions, and prospects are indicated for the further development of BDC materials. Overall, this review will help researchers select excellent strategies for the fabrication of BDC materials, thereby facilitating the use of BDC materials in VRFB design.

Biomass-derived 2D carbon materials: structure, fabrication, and application in electrochemical sensors

Biomass, a renewable hydrocarbon, is one of the favorable sources of advanced carbon materials owing to its abundant resources and diverse molecular structures. Biomass-based two-dimensional carbon nanomaterials (2D-BC) have attracted extensive attention due to their tunable structures and properties, and have been widely used in the design and fabrication of electrochemical sensing platforms. This review embarks on the thermal conversion process of biomass from different sources and the synthesis strategy of 2D-BC materials. The affinity between 2D-BC structure and properties is emphasized. The recent progress in 2D-BC-based electrochemical sensors for health and environmental monitoring is also presented. Finally, the challenges and future development directions related to such materials are proposed in order to promote their further application in the field of electrochemical sensing.

Calcined Chitosan/Cellulous Aerogel Modified with Copper Oxide Nanoparticles as an Efficient Sorbent for the Optimized Removal of Formic Acid from Water

A porous aerogel sorbent was prepared by the carbonization of a biohydrogel consisting of cellulose and chitosan (CS/CE) biopolymers. The adsorbent was also modified with copper oxide nanoparticles to effectively remove formic acid from water in batch mode. Characterization techniques, including scanning electron microscopy, Fourier transform infrared, Brunauer-Emmett-Teller, and X-ray diffraction, were employed to study the prepared sorbents. The concentration of formic acid in the solution was exactly determined by using liquid chromatography. To achieve maximum removal efficiency, important process variables were optimized using a central composite design data-based algorithm. Under optimal conditions, i.e., the initial concentration of 167.98 mg/L, the amount of sorbent equal to 75.28 mg, the contact time of 10.41 min, and the sample volume of 22.56 mL, a maximum acid removal efficiency of 84% was obtained. The Langmuir isotherm model was appropriately fitted to the experimental data, which indicates the chemical interaction of the sorbent active sites with formic acid. An adsorption capacity of 116.28 mg/g was also attained. The adsorption followed a pseudo-second-order kinetic pattern. According to the thermodynamic criteria, the adsorption of formic acid on the copper oxide-modified aerogel was exothermic, entropy-reducing, and favorable at temperatures lower than 290 K. Based on the results, CS/CE hydrogels comprising CuO nanoparticles are promising precursors for synthesizing carbonized aerogel sorbents that are successful in removing formic acid from aqueous environments.

The Preparation of Golgi Apparatus-Targeted Polymer Dots Encapsulated with Carbon Nanodots of Bright Near-Infrared Fluorescence for Long-Term Bioimaging

As a vital organelle in eukaryotic cells, the Golgi apparatus is responsible for processing and transporting proteins in cells. Precisely monitoring the status of the Golgi apparatus with targeted fluorescence imaging technology is of enormous importance but remains a dramatically challenging task. In this study, we demonstrate the construction of the first Golgi apparatus-targeted near-infrared (NIR) fluorescent nanoprobe, termed Golgi-Pdots. As a starting point of our investigation, hydrophobic carbon nanodots (CNDs) with bright NIR fluorescence at 674 nm (fluorescence quantum yield: 12.18%), a narrow emission band of 23 nm, and excellent stability were easily prepared from Magnolia Denudata flowers using an ultrasonic method. Incorporating the CNDs into a polymer matrix modified with Golgi-targeting molecules allowed for the production of the water-soluble Golgi-Pdots, which showed high colloidal stability and similar optical properties compared with pristine CNDs. Further studies revealed that the Golgi-Pdots showed good biocompatibility and Golgi apparatus-targeting capability. Based on these fascinating merits, utilizing Golgi-Pdots for the long-term tracking of the Golgi apparatus inside live cells was immensely successful.

Nitrogen-doped hierarchical porous carbons derived from biomass for oxygen reduction reaction

Nowadays biomass has become important sources for the synthesis of different carbon nanomaterials due to their low cost, easy accessibility, large quantity, and rapid regeneration properties. Although researchers have made great effort to convert different biomass into carbons for oxygen reduction reaction (ORR), few of these materials demonstrated good electrocatalytical performance in acidic medium. In this work, fresh daikon was selected as the precursor to synthesize three dimensional (3D) nitrogen doped carbons with hierarchical porous architecture by simple annealing treatment and NH₃ activation. The daikon-derived material Daikon-NH₃-900 exhibits excellent electrocatalytical performance towards oxygen reduction reaction in both alkaline and acidic medium. Besides, it also shows good durability, CO and methanol tolerance in different electrolytes. Daikon-NH₃-900 was further applied as the cathode catalyst for proton exchange membrane (PEM) fuel cell and shows promising performance with a peak power density up to 245 W/g.