Preparation of porous nitrogen-doped activated carbon derived from rice straw for high-performance supercapacitor application

Rice straw waste-based green synthesis and characterizations investigation of Fe-MoS2-derived nanohybrid

In present work, synthesis of a nanohybrid material using Fe and MoS2 has been performed via a cost-effective and environmentally friendly route for sustainable manufacturing innovation. Rice straw extract was prepared and used as a reducing and chelating agent to synthesize the nanohybrid material by mixing it with molybdenum disulfide (MoS2) and ferric nitrate [Fe (NO3)3.9H2O], followed by heating and calcination. The X-ray diffraction (XRD) pattern confirms the formation of a nanohybrid consisting of monoclinic Fe2(MoO4)3, cubic Fe2.957O4, and orthorhombic FeS with 86% consisting of Fe2(MoO4)3. The properties were analyzed through Fourier-transformed infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results of the dynamic light scattering (DLS) study revealed a heterogeneous size distribution, with an average particle size of 48.42 nm for 18% of particles and 384.54 nm for 82% of particles. Additionally, the zeta potential was measured to be -18.88 mV, suggesting moderate stability. X-ray photoelectron spectroscopy (XPS) results confirmed the presence of both Fe2+ and Fe3+ oxidation states along with the presence of Molybdenum (Mo), oxygen (O), and Sulphur (S). The prepared nanohybrid material exhibited a band gap of 2.95 eV, and the photoluminescence intensity increased almost twice that of bare MoS2. The present work holds potential applications in photo luminescent nanoplatform for biomedical applications.

Recent Advances in Functionalized Biomass-Derived Porous Carbons and their Composites for Hybrid Ion Capacitors

Hybrid ion capacitors (HICs) have aroused extreme interest due to their combined characteristics of energy and power densities. The performance of HICs lies hidden in the electrode materials used for the construction of battery and supercapacitor components. The hunt is always on to locate the best material in terms of cost-effectiveness and overall optimized performance characteristics. Functionalized biomass-derived porous carbons (FBPCs) possess exquisite features including easy synthesis, wide availability, high surface area, large pore volume, tunable pore size, surface functional groups, a wide range of morphologies, and high thermal and chemical stability. FBPCs have found immense use as cathode, anode and dual electrode materials for HICs in the recent literature. The current review is designed around two main concepts which include the synthesis and properties of FBPCs followed by their utilization in various types of HICs. Among monovalent HICs, lithium, sodium, and potassium, are given comprehensive attention, whereas zinc is the only multivalent HIC that is focused upon due to corresponding literature availability. Special attention is also provided to the critical factors that govern the performance of HICs. The review concludes by providing feasible directions for future research in various aspects of FBPCs and their utilization in HICs.

Advancements in Biomass-Derived Activated Carbon for Sustainable Hydrogen Storage: A Comprehensive Review

The increasing global energy demand, which is being driven by population growth and urbanization, necessitates the exploration of sustainable energy sources. While traditional energy generation predominantly relies on fossil fuels, it also contributes to alarming CO2 emissions. Hydrogen has emerged as a promising alternative energy carrier with its zero-carbon emission profile. However, effective hydrogen storage remains a challenge. When exposed to hydrogen, conventional metallic vessels, once considered to be the primary hydrogen carriers, are prone to brittleness-induced cracking. This has spurred interest in alternative storage solutions, particularly porous materials like metal-organic frameworks and activated carbon (AC). Among these, biomass-derived AC stands out for its eco-friendly nature, cost-effectiveness, and optimal adsorption properties. This review offers a comprehensive overview of recent advancements in the synthesis, characterization, and hydrogen storage capabilities of AC. The unique benefits of biomass-derived sources are highlighted, as is the pivotal role of chemical and physical activation processes. Furthermore, we identify existing challenges and propose future research directions in AC-based hydrogen storage. This compilation aims to serve as a foundation for potential innovations in sustainable hydrogen storage solutions.

Phosphorous - Containing Activated Carbon Derived From Natural Honeydew Peel Powers Aqueous Supercapacitors

The introduction of phosphorous (P), and oxygen (O) heteroatoms in the natural honeydew chemical structure is one of the most effective, and practical approaches to synthesizing activated carbon for possible high-performance energy storage applications. The performance metrics of supercapacitors depend on surface functional groups and high-surface-area electrodes that can play a dominant role in areas that require high-power applications. Here, we report a phosphorous and oxygen co-doped honeydew peel-derived activated carbon (HDP-AC) electrode with low surface area for supercapacitor via H3PO4 activation. This activator forms phosphorylation with cellulose fibers in the HDP. The formation of heteroatoms stabilizes the cellulose structure by preventing the formation of levoglucosan (C6H10O5), a cellulose combustion product, which would otherwise offer a pathway for a substantial degradation of cellulose into volatile products. Therefore, heteroatom doping has proved effective, in improving the electrochemical properties of AC-based electrodes for supercapacitors. The specific capacitance of HDP-AC exhibits greatly improved performance with increasing carbon-to-H3PO4 ratio, especially in energy density and power density. The improved performance is attributed to the high phosphorous doping with a hierarchical porous structure, which enables the transportation of ions at higher current rates. The high specific capacitance of 486, and 478 F/g at 0.6, and 1.3 A/g in 1 M H2SO4 electrolyte with a prominent retention of 98.5 % is observed for 2 M H3PO4 having an impregnation ratio of 1 : 4. The higher yield of HDP-AC could only be obtained at an activation temperature of 500 °C with an optimized amount of H3PO4 ratio. The findings suggest that the concentration of heteroatoms as surface functional groups in the synthesized HDP-AC depends on the chosen biomass precursor and the processing conditions. This work opens new avenues for utilizing biomass-derived materials in energy storage, emphasizing the importance of sustainable practices in addressing environmental challenges and advancing toward a greener future.

Biomass-Derived Carbon Materials for Electrochemical Energy Storage

The environmental impact from the waste disposal has been widely concerned around the world. The conversion of wastes to useful resources is important for the sustainable society. As a typical family of wastes, biomass materials basically composed of collagen, protein and lignin are considered as useful resources for recycle and reuse. In recent years, the development of carbon material derived from biomasses, such as plants, crops, animals and their application in electrochemical energy storage have attracted extensive attention. Through the selection of the appropriate biomass, the optimization of the activation method and the control of the pyrolysis temperatures, carbon materials with desired features, such as high-specific surface area, variable porous framework, and controllable heteroatom-doping have been fabricated. Herein, this review summarized the preparation methods, morphologies, heteroatoms doping in the plant/animal-derived carbonaceous materials, and their application as electrode materials for secondary batteries and supercapacitors, and as electrode support for lithium-sulfur batteries. The challenges and prospects for the controllable synthesis and large-scale application of biomass-derived carbonaceous materials have also been outlooked.

Advancements in Olive-derived Carbon: Preparation Methods and Sustainable Applications

In the realm of material science, carbon materials, especially olive-derived carbon (ODC), have become vital due to their sustainability and diverse properties. This review examines the sustainable extraction and use of ODC, a carbohydrate-rich by-product of olive biomass. We focus on innovative preparation techniques like pyrolysis, which are crucial forenhancing ODC's microstructure and surface properties. Variables such as activating agents, impregnation ratios, and pyrolysis conditions significantly influence these properties. ODC's high specific surface area renders it invaluable for applications in energy storage (batteries and supercapacitors) and environmental sectors (water purification, hydrogen storage). Its versatility and accessibility underscore its potential for broad industrial use, makingit as a key element in sustainable development. This review provides a detailed analysis of ODC preparation methodologies, its various applications, and its role in advancing sustainable energy solutions. We highlight the novelty of ODC research and its impact on future studies, establishing this review as a crucial resource for researchers and practitioners in sustainable carbon materials. As global focus shifts towards eco-friendly solutions, ODC emerges as a critical component in shaping a sustainable, innovation-driven future.

ZnO-NPs/AC composite antibacterial agents with N-halamine glycinate functionalized silica-mesoporous silica coating for water disinfection

This work deals with the synthesis, structural characterization and applications of N-halamine glycinate functionalized silica-mesoporous silica coated ZnO-NPs/AC composite for water disinfection. Several nanocomposite materials were obtained: ZnO-NPs/AC, ZnO-NPs/AC@SiO2, ZnO-NPs/AC@SiO2@mSiO2, ZnO-NPs@SiO2@mSiO2-Gly and ZnO-NPs@SiO2@mSiO2-N-halamine-Gly. These nanocomposite materials were fully characterized via different physiochemical techniques including: FTIR, TGA, XPS, XRD, SEM, TEM and BET. XRD indicated a predominance of crystalline pattern of ZnO-NPs impregnated into activated carbon (AC) and their silica and m-mesoporous silica coating precursors. The FTIR spectra confirmed an immense combination between ZnO-NPs and AC of ZnO-NPs/AC nanocomposite as well as its interactions with coated silica precursors. SEM, TEM images illustrated that the fabricated ZnO-NPs/AC nanocomposites are well coated with silica-mesoporous silica functionalized N-halamine. The distinctive surface area has decreased from 800 m2/g for pristine AC to 772 m2/g for ZnO-NPs/AC and to 282 m2/g for ZnO-NPs/AC@SiO2 and to 139 m2/g for ZnO-NPs/AC@SiO2@mSiO2 and to 15.4 m2/g for ZnO-NPs@SiO2@mSiO2-N-Gly. All those nanocomposites showed good efficacy against all four bacterial species, with higher inhibition zones for the 2 g-positive bacteria than that of the 2 g-negative ones. The ZnO@SiO2@mSiO2-N-halamine-Gly exhibited the high zone inhibition against all tested bacteria except for E. Coli.

Utilization of bagasse fly ash for the production of low-cost ammonia adsorbents in poultry farm

NH3 pollution is a significant problem in the poultry farming because excess NH3 can negatively impact chicken health and stunt their growth. Therefore, this study investigated the low-cost production of bagasse fly ash (FA)-a byproduct of the sugar industry-as an NH3 adsorbent. Hydrothermal carbonization and activation were applied to enhance NH3 adsorption using FA. In the experiments, the adsorption capabilities were improved using industrial waste materials mixed with bamboo char or red mud. The experimental results indicate that bagasse FA mixed with bamboo hydrochar under 10 % loading achieved an NH3 adsorption capacity of ∼ 1.02 mg-NH3/g-adsorbent, or ∼ 55 % of that of the commercial adsorbent. To avoid secondary pollution and provide the spent absorbents with an added value, their use in CO2 capture applications was evaluated. The results showed that the adsorbent had a 0.28 mmol-CO2/g-adsorbent capacity.

Valorization of Biomass-Derived Polymers to Functional Biochar Materials for Supercapacitor Applications via Pyrolysis: Advances and Perspectives

Polymers from biomass waste including plant/forest waste, biological industrial process waste, municipal solid waste, algae, and livestock are potential sources for renewable and sustainable resources. Converting biomass-derived polymers to functional biochar materials via pyrolysis is a mature and promising approach as these products can be widely utilized in many areas such as carbon sequestration, power production, environmental remediation, and energy storage. With abundant sources, low cost, and special features, the biochar derived from biological polymeric substances exhibits great potential to be an alternative electrode material of high-performance supercapacitors. To extend this scope of application, synthesis of high-quality biochar will be a key issue. This work systematically reviews the char formation mechanisms and technologies from polymeric substances in biomass waste and introduces energy storage mechanisms of supercapacitors to provide overall insight into the biological polymer-based char material for electrochemical energy storage. Aiming to enhance the capacitance of biochar-derived supercapacitor, recent progress in biochar modification approaches including surface activation, doping, and recombination is also summarized. This review can provide guidance for valorizing biomass waste to functional biochar materials for supercapacitor to meet future needs.

Adsorption of chloramphenicol from water using Carex meyeriana Kunth-derived hierarchical porous carbon with open channel arrays

A carbon material with both open macrochannel arrays and abundant micro/mesopores was prepared, characterized, and applied for removing chloramphenicol (CAP) from water. In the preparation process, Carex meyeriana Kunth (CM) with natural channel arrays was used as the precursor for producing the biochar, and NaOH was used for removing silicon and formatting micro- and mesopores of the porous carbon. The product (PCCM) exhibited the highest specific surface area (2700.24 m² g^-1) among the reported CM-derived porous carbons. The adsorption performances of PCCM were evaluated through batch adsorption experiments. The maximum adsorption capacity of PCCM toward CAP was 1659.43 mg g^-1. The adsorption mechanism was investigated with the aid of theoretical calculations. Moreover, PCCM exhibited better performance than other porous carbon adsorbents in fixed-bed experiments, which may be due to its structural advantages.

Synthesis of carbon molecular sieves from agricultural residues: Status, challenges and prospects

Adsorption is the most promising technology used in the gas separation and purification process. The key success of this technology relies on the selection of an adsorbent. Activated carbon and zeolites are the most commonly used adsorbents in the separation of particular gas from gaseous mixtures. Activated carbon deriving from fossil and biomass-based resources has wide pore size distribution and thereby results in lower selectivity. Whereas, zeolites synthesized from natural minerals are expensive which increases the cost of the purification process. Taking this into concern, the quest for synthesizing low-cost and effective adsorbents has gained greater attention in recent years. Carbon Molecular Sieves (CMSs), are considered as an attractive alternative to replace the conventional adsorbents. Furthermore, CMSs exhibit higher selectivity and adsorption capacity, due to their narrow micropore size distribution (0.3-0.5 nm). CMSs are synthesized from any organic carbonaceous precursor with low inorganic content. Since most of the agricultural residues fall under this category, they can be used as a feedstock for CMSs production. The synthesis of CMSs involves three stages: carbonization, activation, and pore modification. In this review, physicochemical characteristics of various agricultural residues, the effects of carbonization process parameters, activation methods, and pore modification techniques adopted for producing CMSs are comprehensively discussed. The effect of deposition temperature, time, and flow rate of depositing agent on pore characteristics of CMSs is briefed. The prospects and challenges in CMSs production are also studied. The insights in this review provide guidelines for synthesizing CMSs from agro-residues.

Biochar derived carbonaceous material for various environmental applications: Systematic review

Biochar is the solid material produced from the carbonization of organic feedstock biomass. This material has several unique characteristics such as greater carbon content, good electrical conductivity, high stability and large surface area, which can be applied in several research areas such as generation of power and wastewater treatment. In connection with this, recently, the investigations on biochar significantly focus on the removal of toxic heavy metals since the biochar material is easily available and environmentally friendly. According to an environmental analytical device, biochar-derived carbonaceous material has been additionally applied to the synthesis of an effective, sensitive, and low-cost electrochemical sensor. Biochar with an assessment of electrochemical properties has engaged with different redox reactions in water. In this survey, electrochemical ways of behaving of biochar in light of the electrochemical structures were analytically compiled as well as the impact from biomass sources and manufacturing process including carbonization strategies, pre-treatment/changed techniques. This review emphasizes the various synthesis methods of biochar form organic feedstock, properties and different modulations of biochar for the bioremediation of heavy metals. This review study emphasizes the utilization of biochar as sensing platform and supercapacitor for electrode fabrication in electrochemical biosensor to enhance the remediation of toxic contaminants from water streams and by switching the less ecological traditional materials. Brief information on the techniques employed for packaging biochar as carbon electrode is summarized. Scope in the aspect of environmental concern of biochar, future challenges and prospects are proposed in detail.

Hierarchical Porous Heteroatoms-Co-Doped Activated Carbon Synthesized from Coconut Shell and Its Application for Supercapacitors

Coconut husk biomass waste was used as the carbon precursor to develop a simple and economical process for the preparation of hierarchical porous activated carbon, and the electrochemical properties of the electrode material were explored. The important process variables of carbonization, the weight ratios of the coconut shell/KOH, the amount of source dopant, and the carbonization temperature were investigated in order to reveal the influence of the as-obtained microporous/mesoporous/macroporous hierarchical porous carbon materials on the powder properties. Using a BET specific surface area analyzer, Raman analysis, XPS and SEM, surface morphology, pore distribution and specific surface area of the hierarchical porous carbon materials are discussed. The results show that the as-prepared N-, S- and O-heteroatom-co-doped activated carbon electrode was manufactured at 700 °C for electrochemical characteristics. The electrochemical behavior has the characteristics of pseudo-capacitance, and could reach 186 F g^-1 at 1 A g^-1 when measured by the galvanostatic charge-discharge (GCD) test. After 7000 cycles of the charge-discharge test, the initial capacitance value retention rate was 95.6%. It is predicted that capacitor materials made when using coconut shell as a carbon source will have better energy storage performance than traditional carbon supercapacitors.

Waste-converted nitrogen and fluorine co-doped porous carbon nanosheets for high performance supercapacitor with ionic liquid electrolyte

In this work, nitrogen and fluorine co-doped porous carbon nanosheets (NFPCNS) were fabricated from pharmaceutical drug residues derived from the fermentation synthesis of lincomycin hydrochloride via high-temperature pyrolysis and subsequent KOH activation without adding any nitrogen and fluorine reagents. The obtained NFPCNS exhibits an optimized integration of three dimensional interconnected nanosheet structure, large specific surface area of 2912 m² g^-1, hierarchical porous structure with large mesopore proportion (S_meso/S_micro = 151.5%, V_meso/V_micro = 248.2%) and high level heteroatom content (13.2 at.% O, 4.3 at.% N and 1.0 at.% F). Therefore, NFPCNS based supercapacitors using 1-ethyl-3-methylimidazolium tetrafluoroborate electrolyte exhibit an excellent gravimetric capacitance of 296F g^-1 at 1 A g^-1, good rate capability of 65% at 20 A g^-1 and high energy density of 125 Wh kg^-1. Furthermore, an ultra-high energy density of 173 Wh kg^-1 and a long cycling life with 93% capacitance retention after 2000 cycles has been achieved by NFPCNS based supercapacitors with 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide electrolyte. NFPCNS should be a green and efficient electrode materials for next-generation high-energy supercapacitors.

Assessment of antimicrobial, cytotoxicity, and antiviral impact of a green zinc oxide/activated carbon nanocomposite

This work deals with the synthesis of zinc oxide nanoparticles/activated carbon (ZnO NPs/AC) nanocomposites with different weight ratios (3:1, 1:1, and 1:3), where the antimicrobial, antiviral, and cytotoxicity impact of the formulated nanocomposites were evaluated versus the crude ZnO and AC samples. The formula (3:1; designated Z3C1) exhibited the utmost bactericidal effect against Gram positive group, unicellular and filamentous fungi. Regarding Gram negative group, the sample (Z3C1) was remarkably effective against Klebsiella pneumonia, unlike the case of Escherichia coli. Moreover, the whole samples showed negligible cytotoxicity against the human WI38 cell line, where the most brutality (4%) was exerted by 1000 µg/mL of the formula (Z1C3). Whilst, the formula (Z3C1) exerted the apical inhibition impact against Herpes simplex (HSV1) virus. Consequently, the synthesized (Z3C1) nanocomposite was sorted out to be fully characterized via different physicochemical techniques including FTIR, XRD, SEM, TEM, Zeta potential, TGA, and BET. XRD indicated a predominance of the crystalline pattern of ZnO NPs over the amorphous AC, while the FTIR chart confirmed an immense combination between the ZnO NPs and AC. SEM, TEM, and size distribution images illustrated that the fabricated ZnO NPs/AC was in the nanoscale size swung from 30 to 70 nm. The distinctive surface area of composite material, recording 66.27 m²/g, clearly disclosed its bioactivity toward different bacterial, fungal, and virus species.

Porous Biomass Carbon Derived from Clivia miniata Leaves via NaOH Activation for Removal of Dye

Clivia miniata (CM), is an important ornamental plant and has been widely cultivated all over the world. However, there are no reports on Clivia miniata-based porous biomass carbon (CMBC). In this study, for the first time, CM leaves were used to generate porous biomass carbon via NaOH activation. The structures and surface characteristics were determined using scanning electron microscopy, N2 adsorption/desorption, TGA, FT-IR, X-ray diffraction, Raman and X-ray photoelectron spectra tests. CMBC has a large SSA (2716 m2/g) and a total pore volume of 1.95 cm3/g. To test the adsorption performance via adsorption experiments, the cationic and synthetic dye, malachite green (MG), was utilized as the adsorption model. The CMBC had a greatest adsorption capacity of 2622.9 mg/g at a pH value of 8 and had a fastest adsorption capacity of 1161.7 mg/g in the first 5 min. To explain MG adsorption into CMBC, the Freundlich isotherm and the pseudo-second-order kinetic model were used. The adsorption mechanism of MG was also investigated. After 10 cycles, the adsorption efficiency of CMBC to MG could still reach 85.3%. In summary, CMBC has excellent potential in dyeing wastewater pollution treatment.

Biomass derived functional carbon materials for supercapacitor applications

Biochar produced from the thermochemical conversion of biomass, provides a green and sustainable platform for the preparation of various functional carbon materials (porous carbon, heteroatom doped biochar, carbon nanotubes, graphene, carbon quantum dots, etc.) towards advanced application. Their preparation involves the physical as well as chemical activation of biochar or directly from the biomass. The inherent versatile physicochemical properties of these versatile materials have been explored for the construction of the electrochemical energy storage devices like supercapacitors. In the present review, the various methodologies for the preparation of various biomass-derived carbon materials are summarized. Further utilization of these materials in supercapacitor electrodes and the properties associated with their charge storage ability, along with associated challenges and perspectives are also discussed.

Coconut Shell-Derived Activated Carbon for High-Performance Solid-State Supercapacitors

Coconut shells, low-cost and renewable agro-wastes, were used as a starting material in the synthesis of hierarchical activated carbons via hydrothermal, KOH-activation, and carbonization techniques. The ratio of KOH to hydrochar was varied in a systemic manner to study how it influences the texture and electrochemical behavior of the capacitor. Coconut shell-based carbon coated on nickel foams presented a surface area of 1567 m2 g−1, with micropores as well as mesopores widely distributed. The sample showed superior electrochemical performance, attaining 449 F g−1 at 1 A g−1 in 6 M LiNO3 aqueous solution. The solid-state symmetric supercapacitor device delivered a specific capacitance of 88 F g−1 at 1 A g−1 and a high energy density of 48.9 Whkg−1 at a power density of 1 kW kg−1. At a wide voltage window of 2.0 V, the sample was highly stable during the cycle test, showing a 92% capacitance retention at 2 A g−1 after cycling for 5000 times. The superior performance is due to the sample possessing great BET surface area, a good distribution of pores, and the usage of a suitable electrolyte. This facilitates an electrical double layer that can be deployed for applications to store energy.

A novel heterogeneous catalyst NH2-MIL-88/PMo10V2 for the photocatalytic activity enhancement of benzene hydroxylation

In this work, heterogeneous catalyst NH2-MIL-88/PMo10V2-3 has shown the high hydroxylation activity of benzene under visible light (a 5 W LED), which mainly attributed to the production of hydroxyl radical(˙OH) and V5+/V4+ redox pair in the existence of electron (e−).