Biomass-derived Porous Carbon Research Articles

Biomass-derived sulfur-doped porous carbon for CO2 and CH4 selective adsorption

Series of sulfur-doped porous carbons were prepared by using glucose as carbon source and sodium dodecyl sulfate as sulfur source to synthesize sulfur-based carbon precursor and KOH as activator. Pore structure parameters and sulfur content of the prepared carbon materials could be facility regulated by controlling the ratio of KOH/sulfur-based carbon precursor and activation temperature, and their adsorptive separation properties towards CO2 and CH4 were investigated. Results showed that the higher the ultra-microporous volume and the S content of the prepared sulfur-doped porous carbon were, the larger the CO2 and the CH4 adsorption capacity were. The maximum adsorption capacity of CO2 (6.54 mmol/g, 273.15 K and 101 kPa, hereinafter) and CH4 (2.98 mmol/g), and the excellent selectivity of CO2/N2 (75.7) and CH4/N2 (22.8) were achieved by ACS-700-2 because of its higher ultra-microporous pore volume and the highest S content. Permeation experiment, cycle stability test and adsorption thermodynamics experiment show that the prepared S-doped porous carbon had good application potential in the separation and enrichment of CO2 in flue gas and CH4 in coalbed methane. In addition, the pore formation mechanism of sulfur-doped porous carbon was discussed.

Direct activation and hydrophobic modification of biomass-derived hierarchical porous carbon for toluene adsorption under high humidity

Hierarchical porous starch-based carbon (PSC) with tunable pore structure (surface area 1974 ∼ 2721 m2/g and pore volume 0.80 ∼ 1.74 cm3/g) was prepared through direct activation. Due to its high surface area and large pore volume, PSC shows great potential for volatile organic compounds (VOCs) removal. Water vapor commonly exists along with VOCs and the competitive adsorption between VOCs and water vapor would significantly restrict the VOCs adsorption of PSC under high humidity. To address this issue, hydrophobic porous starch-based carbon composite (PSCC) was also prepared by physically mixing PSC with poly-divinylbenzene (PDVB) for toluene adsorption under high humidity to suppress the influence of water vapor. As relative humidity increased from 0 % to 80 %, the toluene adsorption capacity of PSC-2 decreased by 46 % while PSCC only experienced a decrease of 22 %. PSCC could also maintain its toluene adsorption performance (close to 100 %) after five adsorption–desorption cycles. Theoretical computations were also proved that the addition of PDVB inhibits water vapor adsorption and promotes its desorption, thereby enhancing the toluene adsorption of PSCC under high humidity. This work provides a controllable preparation and facile modification of porous carbon to improve its toluene adsorption under high humidity, offering a great application prospect for VOCs removal.

Sustainable synthesis of spongy-like porous carbon for supercapacitive energy storage systems towards pollution control.

In this study, the fruit of Terminalia chebula, commonly known as chebulic myrobalan, is used as the precursor for carbon for its application in supercapacitors. The Terminalia chebula biomass-derived sponge-like porous carbon (TC-SPC) is synthesized using a facile and economical method of pyrolysis. TC-SPC thus obtained is subjected to XRD, FESEM, TEM, HRTEM, XPS, Raman spectroscopy, ATR-FTIR, and nitrogen adsorption-desorption analyses for their structural and chemical composition. The examination revealed that TC-SPC has a crystalline nature and a mesoporous and microporous structure accompanied by a disordered carbon framework that is doped with heteroatoms such as nitrogen and sulfur. Electrochemical studies are performed on TC-SPC using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. TC-SPC contributed a maximum specific capacitance of 145 F g-1 obtained at 1 A g-1. The cyclic stability of TC-SPC is significant with 10,000 cycles, maintaining the capacitance retention value of 96%. The results demonstrated that by turning the fruit of Terminalia chebula into an opulent product, a supercapacitor, TC-SPC generated from biomass has proven to be a potential candidate for energy storage application.

Iron Active Center Coordination Reconstruction in Iron Carbide Modified on Porous Carbon for Superior Overall Water Splitting.

In this work, a novel liquid nitrogen quenching strategy is engineered to fulfill iron active center coordination reconstruction within iron carbide (Fe3C) modified on biomass-derived nitrogen-doped porous carbon (NC) for initiating rapid hydrogen and oxygen evolution, where the chrysanthemum tea (elm seeds, corn leaves, and shaddock peel, etc.) is treated as biomass carbon source within Fe3C and NC. Moreover, the original thermodynamic stability is changed through the corresponding force generated by liquid nitrogen quenching and the phase transformation is induced with rich carbon vacancies with the increasing instantaneous temperature drop amplitude. Noteworthy, the optimizing intermediate absorption/desorption is achieved by new phases, Fe coordination, and carbon vacancies. The Fe3C/NC-550 (550 refers to quenching temperature) demonstrates outstanding overpotential for hydrogen evolution reaction (26.3mV at -10 mAcm-2) and oxygen evolution reaction (281.4 mV at 10mAcm-2), favorable overall water splitting activity (1.57 V at 10 mAcm-2). Density functional theory (DFT) calculations further confirm that liquid nitrogen quenching treatment can enhance the intrinsic electrocatalytic activity efficiently by optimizing the adsorption free energy of reaction intermediates. Overall, the above results authenticate that liquid nitrogen quenching strategy open up new possibilities for obtaining highly active electrocatalysts for the new generation of green energy conversion systems.

Green synthesis of biomass-derived porous carbon with hierarchical pores and enhanced surface area for superior VOCs adsorption

The release of volatile organic compounds (VOCs) during the production, storage, and transportation of petroleum and its derivatives can be hazardous to human health and lead to secondary pollution. Addressing this challenge, this study introduces a sustainable and low-energy approach for synthesizing high-efficiency porous carbon materials, leveraging the abundant and renewable watermelon rinds as a carbon source. The carbonization and activation processes were optimized to minimize energy consumption while maximizing adsorptive performance. In this research, watermelon rinds were used as a source of carbon production, and melamine phosphate (FR-MP) was employed as a modifying agent. The FR-MP modified porous biomass-derived activated carbon (PWAC) was created by subjecting it to physical milling, carbonization, and activation. This approach not only utilized a waste biomass effectively but also reduced the overall carbon footprint of the production process. An examination of the effects of FR-MP dosage on the pore structure, surface chemical properties, and VOCs adsorption abilities of PWAC revealed that a higher FR-MP dosage resulted in a wider range of pore sizes within PWAC. The incorporation of FR-MP intensified the development of internal porosity and pore expansion in PWAC. Specifically, the optimized PWAC-0.3 exhibited a significant increase in specific surface area (3149 m²/g) and pore volume (1.76 cm³/g), enhancing adsorption capacities for acetone and n-hexane up to 1046 mg/g and 760 mg/g, respectively. Furthermore, the PWAC demonstrated exceptional recyclability, maintaining 97% of its original adsorption capacity after five cycles, underscoring its sustainable and economic viability. The highly advanced hierarchical ultra-meso-macroporous structure of PWAC significantly reduced the diffusion resistance of VOCs, guaranteeing swift mass transfer and desorption of VOCs. Consequently, the developed PWAC represents a novel, cost-effective, and environmentally-friendly approach for VOCs adsorption, aligning with the principles of green chemistry and low-energy consumption. This research not only provides a promising solution for VOCs mitigation but also highlights the potential of waste biomass in producing high-performance carbon materials.

Biomass-derived mulberry porous carbon for microwave absorption

In modern electronic devices and communication systems, there is an urgent need for economically viable, environmentally friendly, and efficient absorbing materials. In this work, we have successfully synthesized nitrogen-potassium doped mulberry porous carbon (MBPC) using a one-step pyrolysis strategy for the first time utilizing mulberry as a biomass carbon wave-absorbing material. The resulting MBPC exhibited a porous structure with abundant defects, facilitating the formation of a micro-conductive network and multiple reflection and scattering phenomena, thereby enabling strong microwave absorption. Experimental results demonstrated that the MBPC material achieved a remarkable minimum reflection loss of −44.82 dB at a frequency of 14.64 GHz, along with a maximum effective absorption bandwidth exceeding 5.76 GHz, all within a thickness of only 2.2 mm. Furthermore, by adjusting the thickness between 1 ∼ 3 mm, the bandwidth coverage can be extended to 8.48 ∼ 18 GHz. Computer simulation technology (CST) revealed a high simulated RCS value of 20.68 dB·m2, highlighting its significant practical application potential. This research underscores the promising prospects of mulberry-derived porous carbon as a lightweight, cost-effective, and efficient electromagnetic absorption material.

Exploring Carbonization Temperature to Create Closed Pores for Hard Carbon as High-Performance Sodium-Ion Battery Anodes.

Biomass-derived porous carbon materials are meaningful to employ as a hard carbon precursor for anode materials of sodium-ion batteries (SIBs) from a sustainability perspective. Here, a straightforward approach is proposed to develop rich closed pores in pinenut-derived carbon, with the aim of improving Na+ plateau storage by adjusting the pyrolysis temperature. The optimized sample, namely the pinenut-derived carbon at 1300 °C, demonstrates remarkable reversible specific capacity of 278 mAh g-1, along with a high initial Coulomb efficiency of 85% and robust cycling stability (with a capacity retention of 89% after 800 cycles at 0.2 A g-1). In situ and ex situ analyses unveil that the developed closed pores play a significant role in enhancing the plateau capacity, providing compelling evidence for the "adsorption-filling" mechanism. Moreover, the corresponding full-cell achieves a high energy density of 245.7Wh kg-1 (based on the total weight of both electrode active materials) and exhibits outstanding rate capability (191.4 mAh g-1 at 3 A g-1).

Biomass-derived porous carbon with single-atomic cobalt toward high-performance aqueous zinc-sulfur batteries at room temperature

Aqueous zinc-sulfur batteries at room temperature hold great potential for next-generation energy storage technology due to their low cost, safety and high energy density. However, slow reaction kinetics and high activation energy at the sulfur cathode pose great challenges for the practical applications. Herein, biomass-derived carbon with single-atomic cobalt sites (MMPC-Co) is synthesized as the cathode in Zn-S batteries. The catalysis of single-atom Co sites greatly promotes the transform of cathode electrolyte interface (CEI) on the cathode surface, while offering accelerated charge transfer rate for high conversion reversibility and large electrochemical surface area (ECSA) for high electrocatalytic current. Furthermore, the rich pore structure not only physically limits sulfur loss, but also accelerates the transport of zinc ions. In addition, the large pore volume of MMPC-Co is able to relieve the stress effect caused by the volume expansion of ZnS during charge/discharge cycles, thereby maintaining the stability of electrode structure. Consequently, the sulfur cathode maintains a high specific capacity of 729.96 mA h g−1 after 500 cycles at 4 A g−1, which is much better than most cathode materials reported in the literature. This work provides new insights into the design and development of room-temperature aqueous Zn-S batteries.

Low-cost pyrolysis of biomass-derived nitrogen-doped porous carbon: Chlorella vulgaris replaces melamine as a nitrogen source.

Porous carbon generated from biomass has a rich pore structure, is inexpensive, and has a lot of promise for use as a carbon material for energy storage devices. In this work, nitrogen-doped porous carbon was prepared by co-pyrolysis using bagasse as the precursor and chlorella as the nitrogen source. ZnCl2 acts as both an activator and a nitrogen fixer during activation to generate pores and reduce nitrogen loss. The thermal weight loss experiments showed that the pyrolysis temperatures of bagasse and chlorella overlap, which created the possibility for the synthesis of nitrogen-rich biochar. The optimum sample (ZBC@C-5) possessed a surface area of 1508 m2g-1 with abundant nitrogen-containing functional groups. ZBC@C-5 in the three-electrode system exhibited 244.1F/g at 0.5A/g, which was extremely close to ZBC@M made with melamine as the nitrogen source. This provides new opportunities for the use of low-cost nitrogen sources. Furthermore, the devices exhibit better voltage retention (39%) and capacitance retention (96.3%). The goal of this research is to find a low cost, and effective method for creating nitrogen-doped porous carbon materials with better electrochemical performance for highly valuable applications using bagasse and chlorella.

Improvement in Electrochemical Performance of Waste Sugarcane Bagasse-Derived Carbon via Hybridization with SiO2 Nanospheres.

Sugar industries generate substantial quantities of waste biomass after the extraction of sugar water from sugarcane stems, while biomass-derived porous carbon has currently received huge research attention for its sustainable application in energy storage systems. Hence, we have investigated waste sugarcane bagasse (WSB) as a cheap and potential source of porous carbon for supercapacitors. The electrochemical capacitive performance of WSB-derived carbon was further enhanced through hybridization with silicon dioxide (SiO2) as a cost-effective pseudocapacitance material. Porous WSB-C/SiO2 nanocomposites were prepared via the in situ pyrolysis of tetraethyl orthosilicate (TEOS)-modified WSB biomass. The morphological analysis confirms the pyrolytic growth of SiO2 nanospheres on WSB-C. The electrochemical performance of WSB-C/SiO2 nanocomposites was optimized by varying the SiO2 content, using two different electrolytes. The capacitance of activated WSB-C was remarkably enhanced upon hybridization with SiO2, while the nanocomposite electrode demonstrated superior specific capacitance in 6 M KOH electrolyte compared to neutral Na2SO4 electrolyte. A maximum specific capacitance of 362.3 F/g at 0.25 A/g was achieved for the WSB-C/SiO2 105 nanocomposite. The capacitance retention was slightly lower in nanocomposite electrodes (91.7-86.9%) than in pure WSB-C (97.4%) but still satisfactory. A symmetric WSB-C/SiO2 105//WSB-C/SiO2 105 supercapacitor was fabricated and achieved an energy density of 50.3 Wh kg-1 at a power density of 250 W kg-1, which is substantially higher than the WSB-C//WSB-C supercapacitor (22.1 Wh kg-1).

Hydrophobic modification of walnut shell biomass-derived porous carbon for the adsorption of VOCs at high humidity

Volatile organic compounds (VOCs) often contain water vapor in their exhaust emissions, resulting in the deterioration of the adsorption capacity of activated carbon (AC). A hydrophobic walnut shell biomass-derived AC using polytetrafluoroethylene (PTFE) and polydimethylsiloxane-coated SiO2 (PDMS/SiO2) was developed to improve the selectivity of VOCs under high humidity conditions. These modified ACs were systematically characterized, and dynamic adsorption behaviors of VOCs such as toluene, acetone and their mixtures at the relative humidity (RH) between 0 and 90 % were conducted. The results showed that walnut shell biomass-derived AC has large specific surface area (1853 m2/g) and total pore volume (1.27 cm3/g), strong hydrophilicity (water contact angle of 6.3°), abundant oxygen-containing groups (OH, CO, CO) and aromatic rings. The coating of PDMS/SiO2-PTFE reduces the surface area and total pore volume of AC, but it creates a double-layer rough structure on the AC surface and introduces CF and SiOSi hydrophobic groups, which achieves a water contact angle of 152.8° for 25PSP/AC. The Yoon-Nelson model is suitable to describe the dynamic adsorption process of single- toluene or acetone under dry/humid condition but not suitable for their mixtures. At RH 90 %, PDMS/SiO2-PTFE modified AC significantly increases the adsorption capacity of toluene but is not obviously improved for acetone, which is due to the different polarity of toluene and acetone. PDMS/SiO2-PTFE films on AC have good thermal stability before 500 °C and the hydrophobicity does not change after multi-regeneration at 200 °C. Therefore, PDMS/SiO2-PTFE modified AC has shown great potential as adsorbent to remove the toluene from the humid condition.

High-performance Zn-ion hybrid supercapacitors based on biomass-derived hierarchical porous carbon through template-activated bifunctional induced and ice-crystal assisted strategy

As a highly desirable cathode material for Zn ion hybrid supercapacitors (ZHSCs), biomass-derived carbon precursor shrinks and collapses at elevated temperatures resulting in an impeded internal morphology, which severely hampers ion storage and transport. Herein, a unique porous carbon with multi-level pore structures is produced by a one-step carbonization-activation process. The Gelatin with rich functional groups is employed as the gel-state biomass precursor and the ZnCl2 acted as both a template and an activator. Furthermore, the growth of ice crystals during freeze-drying prevents the carbon framework from collapsing and self-polymerizing of ZnCl2, endowing the prepared porous carbon with a high specific surface area (1336 m2/g) and inheritance of biomass precursor heteroatoms (including N and O). Therefore, at 0.5 A/g, the prepared material displays a desirable specific capacitance of 337.6 F/g in 6 M KOH. In particular, the assembled ZHSC simultaneously shows excellent cycling performance (after 10000 cycles, the specific capacitance increases to 95.6% at 10 A/g) and high energy and power density (120.1 Wh/kg at 450 W/kg). This work provides important insights for the facile preparation of electrode materials for high-performance ZHSCs.

Hierarchical porous biomass-derived carbon with rich nitrogen doping for high-performance microwave absorption and tensile strain sensing

Carbon materials with porous structure and heteroatom doping have been proposed as promising microwave absorption materials. The development of materials with the integration of multiple functions is one of the main development directions and challenges of microwave absorbers. Herein, rich nitrogen-doped biomass-derived carbon (NBC) with coexistence of mesopores and macropores is developed from banana peels by hydrothermal and activation-assisted carbonization methods. The NBC exhibits excellent microwave absorption ability with thin thickness, light weight, broadband and strong absorption features. By mixing with paraffin (5 wt% NBC loading), the minimum reflection loss and effective absorption bandwidth of the composite can reach −53 dB and 4.22 GHz at a thin thickness of 1.70 mm. The corresponding specific reflection loss can reach −311.76 dB/cm, which is among the best of most-reported biomass-derived carbon microwave absorbers. On the other hand, through the reinforcement of thermoplastic polyurethane (TPU), the NBC/TPU composite exhibits good cyclic stability in tensile strain measurements. Furthermore, by integrating the strain sensor with an electrochemical metallization memristor and a resistor, a skin-inspired strain-memory which can retain the information after the remove of external stretch was presented as a proof of concept. This work provides a simple and effective method to develop multifunctional materials for microwave absorption and tensile strain sensing.

Facile synthesis of N-doped biomass derived porous carbon from Opuntia humifusa using simple solid state activation method for reversible capture of volatile iodine

The search for adsorbent materials capable of extracting and storing radioactive iodine derived from nuclear power plants has intensified owing to the growing nuclear waste concerns. Herein, we report a novel method, which is simple and effective, to synthesize biomass-derived porous carbon from an easily available biomass, Opuntia humifusa, via simple solid-state activation with zinc chloride. The resulting porous carbon exhibits a large specific surface area, with up to 1869 m2/g of micropores. The textural properties of activated carbons can be easily modified by adjusting the amount of zinc chloride and activation temperature. The optimal conditions were found to be a ZnCl2 to biomass ratio of 5 and a carbonization temperature of 500 °C. The obtained porous carbons can function as multifunctional solid sorbents for radioactive iodine because of their high porosity and advantageous hierarchical porous structure. Specifically, the obtained activated carbon exhibited high iodine affinity with an absorption of 408 wt%. Considering its global abundance and recyclability, Opuntia humifusa can be used as a new biomass source for the efficient production of highly effective porous carbon materials with potential applications in environmental restoration. Furthermore, the straightforward single-step synthesis method described in this study offers a technique for producing several unique activated mesoporous carbons from various biomasses.

Tailoring moldy-mulberry-derived carbons for ionic liquid-based supercapacitors with ultrahigh energy density

Developing low cost and renewable materials for energy storage is becoming critical for modern society. Biomass-derived porous carbons are promising candidates for constructing high-performance supercapacitors and batteries. To overcome challenges such as the low energy density of carbon, herein three-dimensional interconnected N/P/O co-doped hierarchical porous carbon is fabricated from moldy mulberry/melamine mixture, which possesses a large specific surface area, enhanced surface wettability and fast ions transportation. The thus-improved microstructural properties of N/P/O co-doped carbon boost their supercapacitive performances in aqueous and ionic liquid electrolytes, where specific capacitance of 340 F g−1 at 1.0 A g−1 in KOH solution and capacitance retention of 95.0 % after 25,000 cycles are achieved. Symmetric supercapacitors assembled with such carbon electrodes produce an energy density of 15.5 Wh kg−1 at the power density of 162.3 W kg−1 in KOH solution, and an ultrahigh energy density of 147.6 Wh kg−1 at 900 W kg−1 in EMIMBF4 electrolyte. DFT calculations illustrate that the high N/P doping enhances the electrical conductivity and promotes binding sites for EMIM+ adsorption, hence greatly boosting their supercapacitive capability. These gratifying results demonstrate the feasibility of significantly enhancing electrochemical properties of biomass-derived hierarchical porous carbons with a simple and scalable doping method.

Honeycomb-like hierarchical porous carbon derived from kapok fiber for supercapacitors

The fine structural engineering of biomass-derived porous carbon is the key to maximize the specific capacitance and rate performance of capacitive carbon. Herein, a hierarchical porous carbon (HPC) has been fabricated from kapok fiber via oxalic acid hydrothermal coupled chemical activation strategy. Moderate concentration of oxalic acid hydrothermal treatment is beneficial to increase the concentration of concentration of CO, CO, and sp2 hybrid carbon atoms on fiber surface, and chemical activation accelerate the growth of integrated honeycomb microstructures and hierarchical pores, especially 1.0–2.0 nm micropores. The optimized HPC shows a high specific surface area of 2045 m2 g−1, moderate meso-macropore volume of 0.13 cm3 g−1, low ID/IG of 0.95, and well-developed honeycomb structure, which endows HPC with high ions adsorption capacity and fast kinetic behavior. The optimized HPC exhibits a high specific capacitance of 305.5 F g−1 at 0.5 A g−1 and 194.0 F g−1 at 50 A g−1 in 6 M KOH electrolyte, with a high capacitance retention of 63.5 %. The assembled supercapacitor based on HPC delivers a higher energy density of 10.2 Wh kg−1 at power density of 150 W kg−1 in KOH electrolyte and 27.7 Wh kg−1 at 225 W kg−1 in Na2SO4/PVA gel electrolyte, and superb capacitance retention of 95 % for 20,000 cycles. This will also provide a potential strategy for biomass micro-composition modulation and hierarchical porous carbon structural regulation toward high performance electrode materials.

Sustainable Synthesis of Porous Biomass-Derived Carbon from Tecoma capensis for High Performance Supercapacitors: Characterization and Electrochemical Evaluation

Biowaste carbon products possess interesting physico-chemical properties and are cost-effective due to their remarkable characteristics. Biomass carbon derived from Tecoma capensis (TCL) was processed using pyrolysis at a controlled temperature in an eco-friendly, innovative and sustainable way to develop biomass-derived carbon material. The aim of this study is to demonstrate the facile synthesis of porous carbon compounds from biowaste and evaluate their use in supercapacitors. Various analytical methods, such as structural analysis, morphological studies and electrochemical studies, have been employed to characterize the carbon material generated from biomass. Electrochemical performance evaluation was conducted through cyclic voltammetry and galvanostatic charge-discharge studies utilizing 1 M H2SO4 and 1 M KOH aqueous electrolyte, which exhibited a specific capacitance of 238 F g-1. The outcomes of the studies suggested that the eco-friendly, straightforward process can be utilized to prepare biomass carbon for the electrochemical energy storage applications in an efficient and sustainable manner.

Binary transition metal sulfides MoS2–NiS2 anchored on biomass-derived carbon for improved performance of lithium–sulfur batteries

The poor electrical conductivity of sulfur and electrochemically active solid-state products (Li2Sn, n = 1–3), and the shuttle effect have led to the low cycling stability of lithium-sulfur batteries and the low utilization of the sulfur cathode. In this work, 3D porous biomass-derived carbon material (KMC) was prepared from Miscanthus sinensis by KOH activation. The transition metal sulfide with excellent adsorption and catalytic characteristics was effectively combined with the conductive porous biomass-derived carbon material, and a KMC/MoS2−NiS2 composite material was obtained. The product was characterized by field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. Results show that MoS2−NiS2 nanoparticles can be uniformly distributed on the porous carbon material. Electrochemical measurements reveal that with an initial specific capacity of 1292 mA h g–1 at a current density of 0.1 C. After 400 cycles at 0.5 C, the specific capacity of KMC/MoS2−NiS2/S decays from 1007 to 814 mA h g–1. Thus, the capacity decay rate per cycle is about 0.054 %. This strategy provides a new idea for developing lithium−sulfur batteries with attractive performance.

Green activation method and natural N/O/S co-doped strategy to prepare biomass-derived graded porous carbon for supercapacitors

The sustainable development and high-value utilization of biomass energy were realized by the thermo-chemical method of converting waste biomass into porous carbon materials rich in functional groups and then used in supercapacitors. In this regard, a new method to obtain carbon materials was innovatively proposed in this study by the potassium acetate green activation method coupling natural heteroatom (N, O, S) co-doping strategy. Among them, the co-pyrolysis of spiral algae and bamboo successfully introduced heteroatom functional groups into the microstructure of the carbon materials, which opens up a simple, efficient, and green synthetic route for N/O/S co-doped porous carbon. The results indicated that BC-SA8 provided a capacitance of 320.4 F/g (0.5 A/g) as a carbon electrode in a three-electrode system, depending on its favorable sp2/sp3 hybridization, outstanding microstructure, and abundant heteroatom functional groups. In addition, the symmetric supercapacitor obtained using BC-SA8 exhibited 236.35 F/g at 0.25 A/g. At 10 A/g, SSC/BC-SA8 still had 94.29% capacitance retention after 10,000 cycles. The energy density of SSC/BC-SA8 is 8.21 Wh/kg and 5.42 Wh/kg at 62.5 W/kg and 5000 W/kg power density, respectively. Overall, this work proposed the extraction of heteroatom-rich porous carbon materials from natural biomass by the hybrid pyrolysis technique, laying the foundation for developing green, environmentally friendly, and sustainable heteroatom doping technology.

Multifunctional integration of biomass-derived porous carbon and zirconium dioxide for electrochemical sensing analysis of methyl parathion

We developed an economical and environment-friendly technique for preparing the expired mung bean-derived porous carbon (EMBPC), which possessed large specific surface area and 3D interlinked carbon conductive network. Zirconium dioxide (ZrO2) nanoparticles were further incorporated into the porous structure of EMBPC to form the EMBPC@ZrO2 composite, which was served as electrode sensitizer for the fabrication of EMBPC@ZrO2/GCE sensor. EMBPC exhibited superior conductivity property and large electroactive area, which helped enhance the charge transfer efficiency between electrolyte and sensing electrode. ZrO2 nanoparticles with good biocompatibility achieved the efficient adsorption of methyl parathion (MP) owing to the recognition of ZrO2 towards the phosphate groups of MP. Furthermore, EMBPC with porous carbon conductive structure could make up for the inherent disadvantage of ZrO2 nanoparticles in the term of electrical conductivity. The EMBPC@ZrO2/GCE sensor achieved the highly sensitive MP detection (LOD: 8.77 nM) in linear MP concentration range of 0.01–10 μM. The satisfactory practical property was realized at the EMBPC@ZrO2/GCE sensor with satisfactory recovery rates of 91.95–124.72% and low RSD% of 1.21–3.35% for the electrochemical detection of MP in food samples.