Porous Biocarbon Research Articles

Multistage Template-Oriented Design and Tailoring of the Hierarchical Porous Biocarbon Materials for High-Performance Supercapacitors.

Interfacial regulation is crucial for the enhancement of the specific surface area and supercapacitive performance in porous carbon materials. However, traditional porous carbon obtained through potassium hydroxide activation is confronted with a complicated preparation process. Herein, hierarchical porous biocarbons (HPBC) were facilely prepared by using the multiscale template method and wheat flour as a precursor without any activation. A spherical SiO2 template and wheat flour can be closely combined by gelatinization so as to effectively confine and spatially orient carbon materials. Benefiting from the hierarchical porous structure achieved through the use of templates at different sizes, HPBC-3 has the best electrochemical performance of 223.6 F·g-1 at 1 A·g-1. Moreover, the assembled HPBC-3//HPBC-3 symmetrical supercapacitor demonstrates a remarkable energy density of 15.6 W h·kg-1 and exhibits exceptional cycling performance with a capacitance retention rate of 106% after 5000 cycles. The results fully demonstrate the promising application of the obtained hierarchical porous carbon in supercapacitors.

Construction of NiCo2O4/NiCoO2 co-embedded porous bio-carbon with rich heterogeneous interfaces for excellent bacteriostatic microwave radiation protection

To attain the stable protection against electromagnetic radiation pollution in complex bacterial environment, herein the NiCo2O4 and NiCoO2 co-embedded porous bio-carbon (PBC) with outstanding microwave absorption and anti-bacterial ability was successfully obtained via facile carbonization and immersion-annealing route. The component and microstructure of composites are both tightly affected by the synthetic temperature, which also influences the oxygen vacancy content and defect density within them. The strong interface polarizations from plentiful heterogeneous interfaces and dipole polarizations generated by defects and vacancies contribute greatly to the dielectric absorption, while the eddy-current loss and magnetic resonances have a certain effect as well. Under the matched impedance from magnetic-dielectric balance, the optimized absorption strength of prepared composite achieves −38.2 dB at 2.0 mm thickness with broad absorbing bandwidth of 7.01 GHz for only 2.31 mm. Moreover, the plentiful oxygen vacancies induced reactive oxygen species (ROS) together with heavy metal ions from nickel-cobalt ferrites can suppress the reproduction of Gram negative Escherichia coli (E. coli) and Gram positive Staphylococcus aureus (S. aureus) with anti-bacterial rates of 92.4 % and 93.2 %, respectively. The paper offers a novel insight to design dual-functional microwave absorber with excellent bacteriostatic performance for long-term using in complex bacterial environment.

Almond skin derived porous biocarbon nanoarchitectonics with tunable micro and mesoporosity for CO2 adsorption and supercapacitors

The careful selection of carbon precursors for chemical activation is critical in obtaining cost-effective and efficient porous activated biocarbons with multifunctional properties. Herein, we report on utilising almond skin to synthesize porous activated biocarbons via solid-state KOH activation. Through precise manipulation of the impregnation ratio of KOH to the non-porous carbon, a range of materials with intriguing properties including high surface area, large pore volume, tunable micro and mesopores, and surface functionalization with oxygen were synthesized. The optimized material ASPC5-4 displayed an extremely high surface area (3535 m2 g−1), a large pore volume (1.9 cm3 g−1), a high proportion of mesopores (96.5 %) and a notable surface oxygen content (6.93 wt %). These excellent features allowed ASPC5-4 to adsorb a record amount of CO2 at 0 °C/30 bar (39.81 mmol g−1). Another material ASPC5-2 exhibited a high content of micropores and adsorbed 5.92 mmol g−1 of CO2 at 0 °C/1 bar. ASPC5-4 also exhibited great potential as a supercapacitor electrode, displaying a high specific capacitance in both a three-electrode (354 F g−1/0.5 A g−1) and two-electrode (203 F g−1/0.5 A g−1) systems. It also demonstrated high power and energy densities of 638 W kg−1 and 47 W h kg−1, respectively.

Catalytic degradation of BPA by bamboo leaf-derived KOH-activated porous biocarbon loaded with CoFe2O4-activated peroxymonosulfate

Multiphase catalysts with wide pH, high environmental adaptability, and high activity are urgently needed for the water's contaminants to break down. In this study, the biomass waste bamboo leaves were used as the carbon source and activated by KOH to further increase the active sites (the adsorption capacity was 8.06 times that of the unactivated material) loaded with cobalt ferrite composite catalyst CoFe2O4@PBCX, which could effectively activate the PMS to realize the degradation of BPA. The CoFe2O4@PBCX + PMS system demonstrated remarkable BPA degradation across a broad starting pH range (3–11), and 100% BPA removal was achieved in 9 min at pH=11. CoFe2O4@PBCX achieved excellent BPA removal performance under high salinity conditions (200 mM). The toxicity of BPA and its oxidation intermediates was predicted by the ECOSAR model, which proved that BPA was eventually degraded into non-toxic products. In the bisphenol A degradation device, no catalyst deactivation was observed after 14 h, and 80% removal was maintained after 40 h. This study showed that the synthesized CoFe2O4@PBCX is a highly efficient PMS activation catalyst, which has the potential of low cost, high efficiency, and ecological friendliness in practical wastewater treatment.

Efficient electro-demulsification of O/W emulsions and simultaneous oil removal enabled by a multiscale porous biocarbon electrode

Emulsion wastewater contain substantial amounts of oil and various additives, which pose threats to the environment and human health. Demulsification is a crucial pretreatment stage for wastewater. This study aims to identify a novel electro-demulsification method with high oil removal efficiency and low energy consumption. Modified carbonized birch wood with a unique isotropic multiscale pore structure is used as a self-standing electrode to treat a toluene oil-in-water (O/W) emulsion. The electrode must have a highly porous structure to facilitate efficient water diffusion and oil adsorption. It must also have high electronic conductivity to expedite polarized molecular electrophoresis to realize penetration into the pores and, subsequently, demulsification. Guided by an applied electric field force, polarized O/W droplets are drawn toward the electrode, revealing electrical characteristics distinct from those of polarized organic molecules. This electric field force augments the capture and adhesion of droplets by the electric double layer at the electrode interface. Consequently, adsorbed droplets in close proximity to the electrode rupture due to the combined influence of the electric field force and the electrostatic effects stemming from the electrode's multiscale porous structure. This synergistic action enables demulsification to occur efficiently at low energy consumption levels. This study has revealed that electro-demulsification can effectively treat toluene emulsions stabilized by various surfactants and microemulsion containing toluene. Therefore, this electro-demulsification technology can be further developed for various types of water pollution.

Enhancing Lithium‐Ion Battery Performance with Ni1−xFexS‐Biocarbon Composites: Improving Cycle Stability and Rate Capability through Multilayered Biocarbon Nanosheet Formation and Fe Doping

Given the growing demand for high‐performance, stable, eco‐friendly, and cheap lithium‐ion batteries (LIBs), the development of affordable and environmentally friendly high‐performance anode materials for LIBs has garnered considerable attention. Herein, to address this need, NiS (known for its high theoretical capacity) was grown on a porous biocarbon (BC) matrix to afford a highly conductive LIB anode material capable of accommodating the charge/discharge‐induced volume changes and thus ensuring cycle stability. The cycling performance of this material (NiS–BC) was further enhanced by doping with Fe. The best‐performing (Ni0.8Fe0.2S–BC) anode demonstrated an initial discharge capacity of 1,374.4 mAh g−1 at 0.5 A g−1, which further increased to 1,796.4 mAh g−1 after 100 cycles, and the origins of this high performance were probed by instrumental analysis. The results contribute to the development of next‐generation LIBs for applications requiring high capacity, high output, and long‐term cycle stability, such as electronic devices, electric vehicles, and energy storage systems. Moreover, the use of BC aligns with a prominent trend in modern battery research, namely, the development of secondary batteries simultaneously exhibiting high performance and sustainability.

Enhancing U(VI) removal by using biomass-derived hierarchical porous carbon/α-MnO2 nano fiber composites as high hybrid capacitance electrodes for capacitive deionization

The radioactive pollution caused by uranium containing wastewater generated during the nuclear fuel cycle seriously threatens human health and environmental safety. The electrosorption (or capacitive deionization, CDI) separation of U(VI) from wastewater has the advantages of high efficiency, low energy consumption, convenient operation, and no secondary pollution, making it a promising new separation technology. By combining double layer capacitive materials with pseudo capacitive materials, the specific capacitance and ion storage capacity of the composites can be significantly improved, thereby improving the electrosorption performance. This work used natural biomass as raw material to prepare hierarchical porous biocarbon through high-temperature pyrolysis and chemical activation, and then it was incorporated with hydrothermally synthesized α-MnO2 nanofibers to obtain novel composites (BC/α-MnO2) with high hybrid capacitance for U(VI) removal in CDI. The electrochemical characteristics of the composites and their electrosorption performances for U (VI) were respectively investigated in a three electrode system and a CDI device. The results suggested that BC/α-MnO2 exhibited an ideal capacitive behavior, and theoretical calculations indicated the synergistic effect of capacitive and diffusion control processes on ion storage. Among different BC/α-MnO2 electrodes, BC/α-MnO2-2 had the highest specific capacitance (130.48 F/g) and also the highest adsorption capacity for U (VI) (280.20 mg/g at 0.9 V and pH 4.0). The isotherms and kinetics of U (VI) electrosorption were consistent with the Langmuir and PFO models, respectively. The electrosorption mechanism was mainly related to the contribution of pseudocapacitance and EDL adsorption. Overall, BC/α-MnO2-2 exhibited ideal electrochemical properties and excellent electrsorption performance for U (VI) (high electrosorption capacity, fast kinetic rate, and good cycling stability), facile fabrication and environmentally friendly, and thus it has promising application in CDI treatment of radioactive wastewater.

Highly porous biocarbon monoliths for methane storage

Pollution, resulting from the use of gasoline and diesel fuels, presents an evident concern to environmental health and safety, contributing to greenhouse gases, smog, and a plethora of other hazards to everyday life. A variety of alternative energy sources and technologies are being considered towards the reduction of pollution from the use of fossil fuels, one such being natural gas. The bottleneck of technology for natural gas implementation is the storage and distribution at ambient condition with low-cost media. Activated carbon materials, having been further popularized for their adsorbent properties, have become established as a popular choice for natural gas storage thanks to their high pore volume and surface area and the abundant availability of carbon precursors. Herein, the synthesis of activated carbon monoliths and their application for methane adsorption, as it relates to natural gas storage, is described.

Insights into electro-assisted and selective adsorption of U(VI) using hierarchical porous and activated biocarbon from lotus pods/2D-MoS2/polypyrrole composites through capacitive deionization

The current research work involves the fabrication of orderly mesoporous composite materials based on layered molybdenum disulfide, a hierarchical porous biocarbon from Lotus pods electrodeposited with polypyrrole (2D-MoS2/BCL/PPy). The polypyrrole, as a conducting polymer, was electrodeposited in different mole ratios onto Ni foam supported by 2D-MoS2/BCL. The composite materials were analytically characterized by means of FTIR, SEM-EDX, BET, and XRD techniques. The Lotus pod-driven biocarbon exhibited a high surface area. Among different composites, BCL/PPy-3 (electrodeposited with 0.3 M PPy) was found highly efficient in electro-assisted hexavalent uranium recovery via capacitive deionization because of its impressive specific capacitance (Csp) (100.40 F/g) with improved active surface area and admirable total pore volume. These characteristics made BCL/PPy-3 competitive for enhanced hexavalent uranium ion electrosorption. These features were highly conducive to fast electron transfer and better diffusion of hexavalent uranium ions during the CDI process. The exposed S atoms in BCL/PPy-3 showed good coordination and complexing power for hexavalent uranium ions. The BCL/PPy-3 exhibited an inspiring sorption capacity of 417.90 mg/g at pH = 4.5 and applied voltage (−0.9 V), which is better than many other materials used in CDI applications having similar geometry and morphology. During the electrosorption, the composite electrode BCL/PPy-3 offered a small solution resistance (Rs) (0.69 cm2), a minute charge transfer resistance of Rct (1.19 Ω cm2), and a substantial double layer constant phase element (qdl) of (0.0372 S sn/cm2). These features make this composite electrode highly effective for hexavalent uranium ions removal.

Evaluation of templated N/P co-doped hierarchical mesoporous biocarbon/2D-molybdenum disulfide/polypyrrole composite as a supercapacitor electrode for U(VI) electrosorption

In this work, a templated N/P co-doped hierarchical porous biocarbon was prepared through the carbonization of sugar at high temperature (700 °C). Then, this porous biocarbon was in-situ functionalized with molybdenum disulfide nanosheets through a hydrothermal treatment reaction to get the composite, SC/MoS2. Later, SC/MoS2 on a nickel foam substrate was electrodeposited with different concentrations of polypyrrole, a conducting polymer, at −0.9 V. The prepared composite electrodes (SC/MoS2/PPy) were characterized thoroughly using FTIR, XRD, BET, and SEM. The orderly developed mesoporosity and N, P doping inside the porous carbon network was found to be highly conducive for the U(VI) electrosorption accomplished through capacitive deionization (CDI). The composites had remarkable specific capacitance (95.4 F/g), a large specific surface area (174.4–273.6 m2/g), improved mesopore volume (0.58 cm3/g) and excellent Vm/Vt ratio (0.80). SC/MoS2/PPy-2, among other composites, revealed fast electrosorption kinetics and excellent selectivity with a maximum sorption capacity of 300.66 ± 8.02 mg/g at −0.9 V. The SC/MoS2/PPy-2 retained relatively small charge transfer resistance Rct (1.22 Ω cm2), minute electrolytic resistance Rs (0.77 cm2), and a large double layer constant phase element qdl (0.0369 S sn/cm2) which makes it suitable for U(VI) ion diffusion and fast electron transfer during CDI performance. The composite electrode materials offer novel and potent desalination applications, specifically in uranium extraction from aqueous media.

Comparative study of hydrogen storage in green synthesized porous biocarbon and N/S doped biocarbon

The present work reports the green synthesis and hydrogen storage capacities of porous biocarbon (CK-700) and, N/S doped biocarbon (ACK-1) prepared by green and sustainable carbonization methods from pistachio shells. The hydrogen uptake capacity of CK-700 and ACK-1 were investigated at −196 °C and in the pressure range of 5–50 bar. A green and sustainable route is described for the synthesis of N/S doped biocarbon (ACK-1) by using a combined hydrothermal carbonization and chemical activation process in which Na2S2O3 applied as an activating agent. The characterization of N/S doped biocarbon and raw biocarbon were investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) analyses. The hydrogen storage capacities of the green synthesized CK-700 and ACK-1 were measured by IGA dynamic gas adsorption analyzer. The hydrogen adsorption capacity of CK-700 and ACK-1 were measured and, the highest hydrogen adsorption capacity of ACK-1 was obtained to be 4.55 wt% under pressure of 50 and at 73 K, while the lowest hydrogen uptake capacity of CK-700 was obtained to be 2.24 wt% under pressure of 5 bar and at 73 K in raw biocarbon. HIGHLIGHTS Hydrogen storage capacity of the green synthesized porous biocarbon and N/S doped porous biocarbon were studied. Biocarbon nanoparticles were prepared via green and sustainable method. The addition of sodium thiosulfate as a nontoxic agents plays a synergetic catalytic role. Increase of pore sizes around 765 m2/g in porous N/S doped biocarbon essential for the enhanced hydrogen adsorption.

Biocarbon/polyaniline nanofiber electrodes with high hybrid capacitance and hierarchical porous structure for U(VI) electrosorption

The removal of U(VI) from nuclear effluents is significant for uranium resource recovery and environmental safety. Herein, polyaniline (PANI) was electrodeposited on porous biocarbon (cotton derived carbon, CC) to fabricate a high-performance composite electrode (CC/PANI) for U(VI) electrosorption. The CC/PANI electrode showed high specific capacitance and excellent cyclic stability, it also exhibited capacitive control characteristics for which the capacitance contribution has been quantified. The electrosorption results indicate that CC/PANI-2 has the highest specific capacitance among various CC/PANI electrodes, and also exhibits the highest electrosorption capacity for U(VI), reaching a maximum value of 282.2 mg/g at pH 4.0 and 0.9 V. The modeling results of electrosorption isotherms and kinetics for U(VI) indicated the good simulation by Langmuir and PFO models, respectively. The excellent electrosorption performance of CC/PANI-2 for U (VI) is attributed to its high hybrid capacitance, good conductivity, and improved hydrophilicity. The electrosorption mechanism for U(VI) removal is mainly ascribed to EDL and pseudocapacitive electrosorption, with possible contribution from U(VI) coordination by N atoms of CC/PANI. This work provides the strategy of incorporating PANI with biocarbon to fabricate a novel electrode for the efficient CDI treatment of radioactive nuclear wastewater.

A Green Solution to Energy Storage: Brewers’ Spent Grains Biocarbon–Silica Composites as High‐Performance Lithium‐Ion Batteries Anodes

The demand for more efficient energy storage devices has become increasingly important in order to face the ongoing energy transition. In this regard, it is equally important to attain the production of these devices with the lowest possible environmental impact. In light of this, the use of waste materials and low‐polluting methods has become a strategic priority. In this study, brewers’ spent grains were utilized as raw material to produce anodic electrodes for lithium‐ion batteries (LIBs). The synthesis process involves only two pyrolysis steps at low temperatures without any chemical treatment, reducing energy investment and waste generation. The result is a porous biocarbon structure—with mixed graphitic and amorphous characteristics—decorated with silica nanoparticles. The presence of silica greatly enhances storage capacity. The obtained biocarbon based electrodes exhibites a capacity of 455 mAh g−1 after 100 cycles, surpassing the standard anode material commonly used in commercial LIBs.

Porous biocarbons for ultrasensitive detection of caffeine

In this study, we report the preparation of honeycomb derived porous biocarbon by pyrolysis. Its porous structure was identified by SEM and BET analysis. The electrochemical characteristic of porous carbon modified glassy carbon electrode was studied by cyclic voltammetry and differential pulse voltammetry techniques for caffeine detection. This sensor electrode shows a detection limit of 5.7 μM and high sensitivity of 14,125 μA mΜ−1 cm−2 with a linear response range of 0.02 to 2.0 mM for caffeine detection. This sensor is utilized to detect caffeine concentration in coffee and tea samples.

Renewable Carbon Materials as Electrodes for High-Performance Supercapacitors: From Marine Biowaste to High Specific Surface Area Porous Biocarbons.

Waste, in particular, biowaste, can be a valuable source of novel carbon materials. Renewable carbon materials, such as biomass-derived carbons, have gained significant attention recently as potential electrode materials for various electrochemical devices, including batteries and supercapacitors. The importance of renewable carbon materials as electrodes can be attributed to their sustainability, low cost, high purity, high surface area, and tailored properties. Fish waste recovered from the fish processing industry can be used for energy applications and prioritizing the circular economy principles. Herein, a method is proposed to prepare a high surface area biocarbon from glycogen extracted from mussel cooking wastewater. The biocarbon materials were characterized using a Brunauer-Emmett-Teller surface area analyzer to determine the specific surface area and pore size and by scanning electron microscopy coupled with energy-dispersive X-ray analysis, Raman analysis, attenuated total reflectance Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The electrochemical characterization was performed using a three-electrode system, utilizing a choline chloride-based deep eutectic solvent (DES) as an eco-friendly and sustainable electrolyte. Optimal time and temperature allowed the preparation of glycogen-based carbon materials, with a specific surface area of 1526 m2 g-1, a pore volume of 0.38 cm3 g-1, and an associated specific capacitance of 657 F g-1 at a current density of 1 A g-1, at 30 °C. The optimal material was scaled up to a two-electrode supercapacitor using a DES-based solid-state electrolyte (SSE@DES). This prototype delivered a maximum capacitance of 703 F g-1 at a 1 A g-1 of current density, showing 75% capacitance retention over 1000 cycles, delivering the highest energy density of 0.335 W h kg-1 and power density of 1341 W kg-1. Marine waste can be a sustainable source for producing nanoporous carbon materials to be incorporated as electrode materials in energy storage devices.

CO2 Adsorption on N-Doped Porous Biocarbon Synthesized from Biomass Corncobs in Simulated Flue Gas

This study was to develop a low-cost N-doped porous biocarbon adsorbent that can directly adsorb CO2 in high-temperature flue gas from fossil fuel combustion. The porous biocarbon was prepared by nitrogen doping and nitrogen-oxygen codoping through K2CO3 activation. Results showed that these samples exhibited a high specific surface area of 1209-2307 m2/g with a pore volume of 0.492-0.868 cm3/g and a nitrogen content of 0.41-3.3 wt %. The optimized sample CNNK-1 exhibited a high adsorption capacity of 1.30 and 0.27 mmol/g in the simulated flue gas (14.4 vol % CO2 + 85.6 vol % N2) and a high CO2/N2 selectivity of 80 and 20 at 25 and 100 °C and 1 bar, respectively. Studies revealed that too many microporous pores could hinder CO2 diffusion and adsorption due to the decrease of CO2 partial pressure and thermodynamic driving force in the simulated flue gas. The CO2 adsorption of the samples was mainly chemical adsorption at 100 °C, which depended on the surface nitrogen functional groups. Nitrogen functional groups (pyridinic-N and primary and secondary amines) reacted chemically with CO2 to produce graphitic-N, pyrrolic-like structures, and carboxyl functional groups (-N-COOH). Nitrogen and oxygen codoping increased the amount of nitrogen doping content in the sample, but acidic oxygen functional groups (carboxyl groups, lactones, and phenols) were introduced, which weakened the acid-base interactions between the sample and CO2 molecules. It was demonstrated that SO2 and water vapor had inhibition effects on CO2 adsorption, while NO nearly has no effect on the complex flue gas. Cyclic regenerative adsorption showed that CNNK-1 possessed excellent regeneration and stabilization ability in complex flue gases, indicating that corncob-derived biocarbon had excellent CO2 adsorption in high-temperature flue gas.

Carbon and H2 recoveries from plastic waste by using a metal-free porous biocarbon catalyst

Carbon and H2 recoveries from plastic waste enable high value-added utilizations of plastic waste while minimizing its GHG emissions. The objective of this study is to explore the use of a metal-free biocarbon catalyst for waste plastic pyrolysis and in-line catalytic cracking to produce H2-rich gases and carbon. The results show that the biocarbon catalyst exhibits a good catalytic effect and stability for various plastic wastes. Increasing the C/P ratio from 0 to 2, induce an increase in the conversion rate of C and H in plastics to carbon and H2 from 57.1% to 68.7%, and from 22.7% to 53.5%, respectively. Furthermore, a carbon yield as high as 580.6 mg/gplastic and an H2 yield as high as 68.6 mg/gplastic can be obtained. The hierarchical porous structure with tortuous channels of biocarbon extends the residence time of pyrolysis volatiles in the high-temperature catalytic region and thereby significantly promotes cracking reactions.

The electrosorption of uranium (VI) onto the modified porous biocarbon with ammonia low-temperature plasma: Kinetics and mechanism

Constructing the excellent rich-mesoporous carbon and exploring its electrosorption process are keys to promote the electrosorption industrialization of uranium. In this work, we develop a rich-mesoporous biocarbon by using alkali-thermal-pyrolysis and ammonia low-temperature plasma, and then systematically investigate its electrosorption kinetics and mechanism of U(VI) considering a series of Faradaic side reactions. After the above treatment, the electrosorption efficiency of U(VI) onto biocarbon improves from 49.75% to 94.45%, and the ultra-high U-selectivity coefficient (SU/M) is higher than 120 from the mixed solution. The kinetic diffusion process of U(VI) into the pores is crucial, even in different water systems. Importantly, Faradaic side reactions are proved to be non-negligible factors in the electrosorption of uranium. Especially, the oxygen reduction at the cathode can convert dissolved oxygen into H2O2, which oxides the amorphous electro-reduced U(V, IV) to U(VI), and finally forms crystalline uranium peroxide species. To sum up, this work not only offers an excellent uranium-selectivity electroadsorbent, but firstly confirms the influence of Faradaic side reactions that has been ignored in the current electrosorption of uranium.

Rapid preparation of porous carbon by flame burning carbonization method for supercapacitor

Herein, the feasibility of simple and quick to fabricate porous biocarbon materials by a universal flame burning carbonization synthetic strategy is investigated. Cotton, dandelion and catkin are fluffy that contain lots of air between the tissues, which are low ignition point and flammable substances, they are easily lighted and carbonized. K2CO3-KCl not only play the role of activator and template agent, but also cover the surface of substance in the form of molten state to isolate air with biocarbon and prevent the burn out of biomass. The prepared carbon has hierarchical porous structure, large specific surface area and abundant heteroatoms doping, and can reach a high specific capacitance of 367 F g−1 in 6 M KOH. In addition, we also prepare a large voltage window of K2CO3-glycol-arginine electrolyte, and the assembled symmetric supercapacitor with the prepared electrolyte and porous carbon exhibits an energy density of 30.7 Wh kg−1 and a wide operating temperature from −25 to 100 °C. The practicable of flame burning rapid carbonization strategy, recycling K salt and large-scale production are verified. This study uncovers a new possibility for the rapid and commercial production of biomass based porous carbon materials for high performance supercapacitor.

Inspired by plants: Carbonization mechanism, micro architecture and electrochemical applications of corn stalks

Plants possess the natural organic composite frameworks and the desirable micro-architecture, which are one kind of the promising precursors of porous carbons. In this work, corn stalks are studied as carbon precursors for the efficient utilization of their sponge-like tissue. Unlike other reported works, this study focuses on the carbonization mechanism of corn stalks and the inherited process from the organic composite tissues to carbon frameworks. After three carbonization stages, the cellular-like porous biocarbons with the replicated biological structures were generated from corn stalks. It is found that the lignin-networks wrapped on cellulose and hemicellulose will become into the main composition of the carbon-skeletons. The gas-phase products derived from carbohydrates promoted the lignin carbonization into porous carbon frameworks, which inherit the cellular structure and the anisotropy of plant tissues. Based on our discovery, the ruthenium nanoparticles are prepared by using the spontaneous capillary action and the steric hindrance of plant tissues. Due to the high-dispersion active particles and the accelerated mass transfer, the in-situ prepared composite electrocatalysts exhibit high performance towards the hydrogen evolution reaction. This study provides a new idea to establish an environmentally sustainable solution of agricultural waste and the utilization of plants natural structures for high-performance applications.