Graphitic carbon @ silver nanoparticle @ porous silicon Bragg mirror composite SERS substrate for gallic acid detection.

Graphite carbon (G) @ silver (Ag) @ porous silicon Bragg mirror (PSB) composite SERS substrate was successfully synthesized using electrochemical etching (ec) and hydrothermal carbonization (HTC) techniques with silver nitrate as the source of silver and glucose as the source of carbon. The PSB was used as a functional scaffold for the synthesis of graphite-carbon and silver composite nanoparticles (G@AgNPs) on its surface, thereby combining SERS activity and antioxidant properties. To our knowledge, this is the first time that G@AgNPs has been synthesized on the PSB using glucose as a carbon source. The synthesized G@Ag@PSB was utilized as a SERS platform for the detection of gallic acid (GA). Test results demonstrated that the substrate exhibited a remarkable SERS enhancement capability for GA, with the enhancement factor (EF) reaching 2 × 105. The reproducibility of the SERS spectral signal was excellent, with a relative standard deviation (RSD) of 7.5 %. The sensitivity test results showed that the linear range of GA detection based on G@Ag@PSB composite SERS substrate was 2 × 10-3-2 × 10-12M. The relationship between GA concentration and SERS signal intensity exhibited a strong linear correlation, with a linear correlation coefficient (R2) of 0.97634. Moreover, even with an extended storage period, only a marginal decline in the signal intensity of GA on the substrate was observed. The results of this study demonstrate that the prepared G@Ag@PSB composite SERS substrate had good potential application performance as a low-cost SERS detection platform suitable for commercial use. In addition, this advance facilitates the further exploration of more nanomaterials with ultra-high sensitivity in SERS technology.

The Formation Mechanism of Carbonized Polymer Dots: Crosslinking-Induced Nucleation and Carbonization.

Carbon dots (CDs), as a kind of zero-dimensional nanomaterials, have been widely synthesized by bottom-up methods from various precursors. However, the formation mechanism is still unclear and controversial, which also brings difficulty to the regulation of structures and properties. Only some tentative formation processes were postulated by analyzing the products obtained at different reaction times and temperatures. Here, the effect of crosslinking on the formation of carbonized polymer dots (CPDs) is explored. Crosslinking-induced nucleation and carbonization (CINC) is proposed as the driving force for the formation of CPDs. Under hydrothermal synthesis, the precursors are initiated to polymerize and crosslink. The crosslinking brings higher hydrophobicity to generate the hydrophilic/hydrophobic microphase separation, which promotes dehydration and carbonization resulting in the formation of CPDs. Based on the principle of CINC, the influence factors of size are also revealed. Moreover, the dissipative particle dynamics (DPD) simulation is employed to support this formation mechanism. This concept of CINC will bring light to the formation process of CPDs, as well as facilitate the regulation of CPDs' size and photoluminescence.

Artificial humic acid produced from wet distillers grains in a microwave-assisted hydrothermal process: Physicochemical characteristics and stimulation to plant growth.

Wet distillers grains, as a waste biomass with a large annual output, pose a threat to the environment and food industry. Herein, artificial humic acid (AHA) was first produced from wet distillers grains in a dual-stage microwave-assisted hydrothermal process. The influence of temperature on AHA's characteristics was investigated and compared with natural humic acid (NHA) and standard humic acid (SHA). A high yield of AHA at 20.6% was obtained at 200 °C with a total reaction time of 1 h, which is 1.8-3.1 times that obtained in traditional single-stage hydrothermal process. Increasing the reaction temperature induced the formation of phenolic hydroxyl in AHA. AHA was rich in aromaticity and carboxylic acid structure, showing similar spectral characteristics to NHA. The distribution of molecular weight of AHA was mostly 5797 Da, which decreased by 15% compared to SHA. The optimal concentration of AHA to promote seedling growth was 0.2 g/L, and the root length was 2.0 times that of the control. The microwave hydrothermal process is a facile and efficient approach to preparing AHA from waste biomass with high moisture content.

Efficient selective adsorption of Cr(VI) by S-doped porous carbon prepared from industrial lignin: Waste increment and wastewater treatment.

Industrial lignin is a waste product of the paper industry, which contains a large amount of oxygen group structure, and can be used to treat industrial wastewater containing Cr(VI). However, lignin has very low reactivity, so how to enhance its adsorption performance is a major challenge at present. In this study, a two-stage hydrothermal and activation strategy was used to activate the lignin activity and doping S element to prepare high-performance S-doped lignin-based polyporous carbon (S-LPC). The results show that the surface of S-LPC is rich in S and O groups and has a well-developed pore structure, which is very beneficial to Cr(VI) uptake -reduction and mass transfer on the material. In the wastewater, the utmost adsorption potential of Cr(VI) by S-LPC achieved 882.83 mg/g. After 7 cycles of regeneration, the adsorption of S-LPC decreased by only approximately 18 %. Ion competition experiments showed that S-LPC has excellent specificity for Cr(VI) adsorption. In factory wastewater, the adsorption performance of S-LPC for Cr(VI) remained above 95 %, which shows the excellent performance of S-LPC in practical applications. The results are of great significance for green chemical utilization of waste lignin, treatment of industrial wastewater and sustainable development.

Evaluation of South Korean marine waste resources for hydrochar production: Effect of process variables.

This study assessed the hydrochar production potential of fish and crustacean waste from 8 marine species (Scomber japonicus, Trichiurus lepturus, Larimichthys polyactis, Trachurus trachurus, Paralichthys olivaceus Litopenaeus vannamei, Portunus trituberculatus, and Penaeus monodon) through hydrothermal carbonization (HTC) of their waste fractions. The impact of reaction temperature (200 - 240°C), fixed residence time (5 h), and water-to-biomass ratio (7) on HTC was analyzed. The results showed that hydrochar yields varied between fish (15.1 - 21.5 %) and crustaceans (36.9 - 69.3 %). The elemental composition and surface properties of the hydrochar were influenced by reaction temperature, as indicated by the pH point of zero charge. The adsorption capacity of hydrochar was tested for methylene blue (MB, 2.7 - 10.8 mg/g) and methyl orange (MO, 5.9 - 9.2 mg/g), with MO showing higher adsorption, except for Scomber japonicus, Larimichthys polyactis, and Trachurus trachurus. These findings highlight the significant potential for converting marine waste into valuable hydrochar, contributing to waste management and sustainable resource utilization.

Microalgal-based carbon encapsulated iron nanoparticles for the removal of pharmaceutical compounds from wastewater.

This study evaluates the effectiveness of microalgal-based carbon-encapsulated iron nanoparticles (ME-nFe) in the removal of pharmaceutical compounds (PhACs) from water solutions and real municipal effluent at a laboratory scale. The investigated PhACs were chosen to represent different classes of synthetic drugs: antibiotics, anti-inflammatory drugs, antihypertensives, antiepileptics, neuroprotectors, and antidepressants. The adsorbent material was produced through hydrothermal carbonization (225 °C for 3 h), using microalgae grown on wastewater as the carbon source. ME-nFe showed heterogeneity in terms of porosity (with both abundance of macro and mesopores), a total pore volume of 0.65 mL g-1, a specific surface area of 117 m2 g-1 and a total iron content of 40%. Laboratory scale adsorption tests (1 g L-1 of nanoparticles with 2 min contact time) showed high removal for the most hydrophobic compounds. Removal efficiencies were high (over 98%) for Irbesartan, Ofloxacin and Diclofenac, promising (over 65-80%) for Clarithromycin, Fluoxetine, Lamotrigine and Metoprolol, but low for Gabapentin-Lactam and Propyphenazone (<20%). Electrostatic interactions between the drugs and the surface of the nanoparticles may account for the observed data, although additional removal mechanisms cannot be ruled out.

Synthesis of hydrochar from date palm seeds using microwave-enhanced hydrothermal carbonization and its application in dyes removal.

This work reports new findings on the preparation of hydrochar from date palm (Phoenix dactylifera) seeds through the application of the microwave hydrothermal carbonization (HTC) method. Optimization investigations involving temperatures and reaction times were conducted to establish the highest yield, achieving a maximum yield of 60.87%. The prepared material was then impregnated in phosphoric acid and carbonized in the tube furnace at 550 °C for 1.5 h with a nitrogen flow of 50 CCM. The samples were characterized via scanning electron microscopy (SEM), Brunauer-Emmet-Teller (BET) and Fourier transform infrared (FTIR). The samples showed remarkable BET surface areas following activation, reaching up to 992 m2·g-1. The substance was subsequently used to absorb methylene blue with good fitting to the Freundlich and Redlich-Peterson isotherm and achieved a peak adsorption capacity of 196.6 ± 3.9 mg·g-1.

This study involves the preparation of hydrochar through microwave-assisted hydrothermal carbonization (HTC) of date palm seeds. It explores the impact of different process parameters, such as power, reaction temperatures, and timing on the mass yield and BET surface area of the hydrochars. Additionally, the prepared material undergoes chemical activation with phosphoric acid, and its efficacy in extracting methylene blue (MB) from an aqueous solution is assessed. This research is particularly novel as it represents the first comprehensive investigation into the use of microwave-derived and phosphoric acid-activated hydrochar for MB extraction.

Hydrochar from Pine Needles as a Green Alternative for Catalytic Electrodes in Energy Applications.

Hydrothermal carbonization (HTC) serves as a sustainable method to transform pine needle waste into nitrogen-doped (N-doped) hydrochars. The primary focus is on evaluating these hydrochars as catalytic electrodes for the oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO2RR), which are pivotal processes with significant environmental implications. Hydrochars were synthesized by varying the parameters such as nitrogen loading, temperature, and residence time. These materials were then thoroughly characterized using diverse analytical techniques, including elemental analysis, density measurements, BET surface area analysis, and spectroscopies like Raman, FTIR, and XPS, along with optical and scanning electron microscopies. The subsequent electrochemical assessment involved preparing electrocatalytic inks by combining hydrochars with an anion exchange ionomer (AEI) to leverage their synergistic effects. To the best of our knowledge, there are no previous reports on catalytic electrodes that simultaneously incorporate both a hydrochar and AEI. Evaluation metrics such as current densities, onset and half-wave potentials, and Koutecky-Levich and Tafel plots provided insights into their electrocatalytic performances. Notably, hydrochars synthesized at 230 °C exhibited an onset potential of 0.92 V vs. RHE, marking the highest reported value for a hydrochar. They also facilitated the exchange of four electrons at 0.26 V vs. RHE in the ORR. Additionally, the CO2RR yielded valuable C2 products like acetaldehyde and acetate. These findings highlight the remarkable electrocatalytic activity of the optimized hydrochars, which could be attributed, at least in part, to their optimal porosity.

Unveiling drastic influence of cross-interactions in hydrothermal carbonization of spirulina with cellulose, lignin or poplar on nature of hydrochar and activated carbon.

Spirulina platensis contains abundant nitrogen-containing organics, which might react with derivatives of cellulose/lignin during hydrothermal carbonization (HTC), probably affecting yield, property of hydrochar, and pore development in activation of hydrochar. This was investigated herein by conducting co-HTC of spirulina platensis with cellulose, lignin, and sawdust at 260 °C and subsequent activation of the resulting hydrochars with K2C2O4 at 800 °C. The results showed that cross-condensation of spirulina platensis-derived proteins with cellulose/lignin-derived ketones and phenolics did take place in the co-HTC, forming more π-conjugated heavier organics, retaining more nitrogen species in hydrochar, reducing yields of hydrochar, making the hydrochar more aromatic and increasing the thermal stability and resistivity towards activation. This enhanced the yield of activated carbon (AC) by 7 %-20 % and significantly increased specific surface area of the AC from activation of hydrochar of spirulina platensis + lignin to 2074.5 m2/g (859.3 m2/g from spirulina platensis only and 1170.1 m2/g from lignin only). Furthermore, more mesopores from activation of hydrochar of spirulina platensis + cellulose (47 %) and more micropores from activation of hydrochar of spirulina + sawdust (93 %) was generated. The AC from spirulina platensis + lignin with the developed pore structures generated sufficient sites for adsorption of tetracycline from aqueous phase and minimized steric hindrance for mass transfer with the abundant mesopores (43 %).

Preparation of cellulose derived carbon/reduced graphene oxide composite aerogels for broadband and efficient microwave dissipation.

The development of cellulose derived carbon-based composite aerogels with light weight, broad bandwidth and strong absorption remains a challenging task. In this work, the cellulose derived carbon/reduced graphene oxide composite aerogels were prepared by a two-stage process of chemical crosslinking and high-temperature carbonization. The results revealed that the as-fabricated binary composite aerogels had a unique lightweight characteristic and three-dimensional porous network structure, which was chemically crosslinked by epichlorohydrin. Furthermore, the weight concentration of graphene oxide (GO) had a notable influence on the electromagnetic parameters and microwave absorption properties of the composite aerogels. The obtained binary composite aerogel possessed the optimal microwave dissipation capability when the concentration of GO was 1.5 mg/mL. Remarkably, the minimum reflection loss reached -50.42 dB at a thickness of 2.47 mm and a filling ratio of 17.5 wt%. Concurrently, the composite aerogel with a comparable thickness of 2.73 mm showed a wide effective absorption bandwidth of 7.28 GHz, spanning the total Ku-band and extending into a portion of the X-band. The radar cross section contribution of binary composite aerogels in the far-field was also simulated by computer simulation technique. In addition, the potential microwave attenuation mechanism was proposed. It was believed that the results of this paper would offer a reference for the preparation of cellulose derived carbon-based composite aerogels as efficient and broadband microwave absorbers.

Bio-Skin-Inspired Flexible Pressure Sensor Based on Carbonized Cotton Fabric for Human Activity Monitoring.

With the development of technology, people's demand for pressure sensors with high sensitivity and a wide working range is increasing. An effective way to achieve this goal is simulating human skin. Herein, we propose a facile, low-cost, and reproducible method for preparing a skin-like multi-layer flexible pressure sensor (MFPS) device with high sensitivity (5.51 kPa-1 from 0 to 30 kPa) and wide working pressure range (0-200 kPa) by assembling carbonized fabrics and micro-wrinkle-structured Ag@rGO electrodes layer by layer. In addition, the highly imitated skin structure also provides the device with an extremely short response time (60/90 ms) and stable durability (over 3000 cycles). Importantly, we integrated multiple sensor devices into gloves to monitor finger movements and behaviors. In summary, the skin-like MFPS device has significant potential for real-time monitoring of human activities in the field of flexible wearable electronics and human-machine interaction.

Synthesis of Carbon Dots via Microwave-Assisted Process: Specific Sensing of Fe(III) and Antibacterial Activity.

Carbon dots synthesized from a renewable and sustainable source of biomass have greater attention in the nanomaterial research field. In the present study, we adopted a facile and green synthesis of carbon dots from bio waste of pumpkin seeds using a one-pot microwave-assisted carbonization method. The synthesized carbon dots exhibit excellent photoluminescence properties with a bright blue emission peak at 399 nm and fluorescence quantum yield was about 9.5%. The optical properties and structure of carbon dots were examined using various spectroscopy techniques and the synthesized carbon practical size was about 4.37 nm and possessed good solubility in water. Carbon dots were used for the detection of Ferric ions in the water bodies and the interaction between Fe3+ ions and carbon dots was evaluated by fluorescence spectroscopy techniques. This method is a simple and selective detection of Fe3+ in the aqueous medium. Interestingly carbon dots also show good antibacterial activity at a very low concentration (1 mg/L) for effective control of E. coli 93% and Pseudomonas aeruginosa (81%), within 12 h.

The effect of an acidic environment during the hydrothermal carbonization of sewage sludge on solid and liquid products: The fate of heavy metals, phosphorus and other compounds.

The pH of sewage sludge is a crucial factor during the hydrothermal carbonization process that influences the characteristics of the resulting products and migration of certain compounds from the solid to liquid phase. Accordingly, this work is focused on examining the pH impact during the HTC process, in particular, pH equals 2, 3, 4, 5 and 6 on the individual hydrothermally carbonized products generated at 200 °C and 2 h residence time. For this reason, the chemical and physical indicators describing the post-processing liquid and hydrochar were determined. For instance, it was observed that the phosphorus content detected in the liquid, derived at pH2, rose significantly by 80%. Furthermore, decreasing the pH of sewage sludge had a significant impact on the ash content and the calorific value of the hydrochar. Additionally, changes in the specific surface area of hydrochar were noticed: pH = 5 and pH = 6 showed an increase of 20-30%, while for lower pH values a decrease of c.a. 26% was achieved. The distribution of heavy metals between the obtained fractions in the HTC process (solid and liquid) indicated that 92 to almost 100% of the tested heavy metals were transferred to the hydrochar. A significant effect of pH on the distribution between these fractions was observed only for Zn and Ni. For instance, for pH = 2, Zn and Ni in post-processing liquid were 34% and 29%, respectively. In addition, the sequential extraction of heavy metals from hydrochar was also performed in order to identify mobile and non-mobile phases. It was noticed that the acidic environment favours a higher amount of mobile heavy metals in hydrochar. The largest effect was observed for Cd, Pb, Cr and Cu, for which, at pH = 2, their respective amounts in the mobile fraction were 2.7; 3.6; 1.8; 6.2 times higher, compared to the hydrochar without pH correction.

Onion husk-derived high surface area graphene-like carbon for supercapacitor electrode material application.

In this study, we report the synthesis of graphene-like carbon derived from onion husk, with potential application as an electrode material in energy storage devices. Graphene-like carbon (GLC) was synthesized from onion husk (OH) by preliminary carbonization at 550 °C, followed by thermochemical activation at various temperatures to determine the optimal activation parameters. The surface morphology of graphene-like carbon from onion husk (GLC-OH) samples after carbonization shows distinct thermal exfoliation of the material. This layering upon activation in KOH promotes the formation of highly porous graphene-like carbon flakes. According to the Brunauer-Emmett-Teller (BET) method, the specific surface area at 850 °C was 1924 m2/g. The X-ray diffraction (XRD) and Raman spectroscopy results reveal the emergence of few-layer graphene with a significant amount of structural defects at 850 °C. As the temperature increases, the formation shifts towards multilayer graphene, which leads to a decrease in the specific surface area of the carbon material. The electrochemical characterization of the assembled GLC-OH-based supercapacitor synthesized at 850 °C revealed a markedly higher specific capacitance value of 131 F/g, along with a Coulombic efficiency of 98 % at a gravimetric current density of 1 A/g. Additionally, it exhibited a low charge transfer resistance (RCT) of approximately 1.4 Ω. Our study investigates the influence of structural changes on the electrochemical performance of biomass-derived activated carbon, highlighting the potential of graphene-like carbon from onion husk as a promising and low-cost material for future energy storage devices.

A solid acid derived from fishbone catalyzes the hydrolysis of cellulose into nanocellulose.

The necessity to look into waste biomass resource regeneration has increased due to growing environmental and energy-related problems. This study successfully developed an innovative fishbone-derived carbon-based solid acid catalyst using the carbonation-sulfonation method, which was subsequently applied to catalyze the hydrolysis of cellulose to produce nanocellulose. The data analysis reveals that the sulfonation treatment affects the microstructure of the catalyst, resulting in a decline in its specific surface area (134.48 m2/g decreased to 9.66 m2/g). However, this treatment doesn't hinder the introduction of acidic functional groups. In particular, the solid acid catalyst derived from fishbone exhibited a total acid content of 3.76 mmol/g, with a concentration of -SO3H groups at 0.48 mmol/g. Furthermore, the solid acids originating from fishbones manifested remarkable thermal stability, exhibiting a mass loss of <15 % at temperatures up to 600 °C. Moreover, the catalyst displayed exceptional catalytic performance during the cellulose hydrolysis reaction, achieving an optimum nanocellulose yield of 45.7 % at an optimized reaction condition. An additional noteworthy feature is the solid acid catalyst's impressive recyclability, maintaining a nanocellulose yield of 44.87 % even after undergoing five consecutive usage cycles. This research outcome underscores an innovative approach to for the sustainable utilization of waste biomass resources.

Rational design of Fe, N co-doped porous carbon derived from conjugated microporous polymer as an electrocatalytic platform for oxygen reduction reaction.

Porous iron-nitrogen-doped carbons (FeNC) offer a great platform for construction of cathodic oxygen reduction reaction (ORR) catalysts in fuel cells. However, challenges still remain regarding with the collapse of carbon-skeleton during pyrolysis, uneven distribution of active sites and aggregation of metal atoms. In this work, we synthesized Fe, N co-doped conjugated microporous polymer (FeN-CMP) through a facile bottom-up strategy using 1,3,5-triethynylbenzene and iron-chelated 3,8-dibromo-1,10-phenanthroline as monomers, ensuring the uniform coordination of N with Fe element in network. Then, the resulting FeN-CMP was treated by pyrolysis without structural collapse to obtain porous FeNC electrocatalyst for ORR. The most active catalyst was fabricated under 900 °C, which exhibits remarkable ORR activity in alkaline medium with half-wave potential of 0.796 V (18 mV and 105 mV positive deviation from the commercial Pt/C catalyst and post-doping catalyst), high selectivity with nearly 4e- transfer process and excellent methanol tolerance. Our study first developed porous FeNC electrocatalysts derived from Fe, N-anchoring CMPs based on pre-functionalization of monomers, which exhibits great potential as an alternative to commercial Pt/C catalyst for ORR, and provides a feasible strategy of developing multi-atoms doping catalysts for energy storage and conversion as well as heterogeneous catalysis.

Enhancing sustainable waste management: Hydrothermal carbonization of polyethylene terephthalate and polystyrene plastics for energy recovery.

Hydrothermal carbonization (HTC) of single plastic polymers such as polyethylene terephthalate (PET) and polystyrene (PS) has not yet been explored on a large scale, particularly their thermal behavior, chemical transformations under subcritical conditions, and the energy properties of the resultant hydrochar. This study investigated these aspects by employing techniques, such as thermogravimetric analysis (TGA), Fourier transformed infrared spectroscopy (FTIR), elemental and calorific analysis. The results show that PET hydrochar has a superior energy densification (1.37) and energy yield (89 %) compared to PS hydrochar (1.13, 54 %). Hydrothermal carbonization modifies the chemical structure of the polymers by increasing the number of carbonyl groups (CO) in PET and forming new ones in PS, and by enhancing hydroxyl groups (OH) in PET while retaining them in PS. Both materials preserve their aromatic and aliphatic structures, with the introduction of alkenes groups (CC) in the PET hydrochar. PET hydrochar begins to decompose at lower temperatures (150-270 °C) than PS hydrochar (242-283 °C) but reaches higher peak temperatures (420-585 °C vs. 390-470 °C), with both types achieving similar burnout temperatures (650-800 °C). PET hydrochar recorded a higher activation energy (121-126 kJ/mol) than PS hydrochar (67-74 kJ/mol) with the Mampel first-order reaction model as the best fit.

Treatment of swine manure by hydrothermal carbonization: The influential effect and preliminary mechanism of surfactants.

Treatment of swine manure by hydrothermal carbonization (HTC) with the aid of different surfactants was first explored in this study. PEG 400 (polyethylene glycol 400) and Tween 80 facilitated the formation of bio-oil. SLS (sodium lignosulfonate) and SDS (sodium dodecyl sulfate) promoted the formation of water-soluble matters/gases. Span 80 enhanced the formation of hydrochar, which resulted in a 50.19 % mass yield, 92.39 % energy yield, and a caloric value of 28.68 MJ/kg. The hydrochar obtained with Span 80 presented a similar combustion performance to raw swine manure and the best pyrolysis performance. The use of Span 80 promoted the transfer of degradation products to hydrochar, especially hydrophobic ester and ketone compounds. Notedly, Span 80 suppressed the synthesis of PAHs during the HTC process, which was reduced to 0.92 mg/kg. Furthermore, the hydrochar produced with Span 80 contained lower contents of heavy metals. On the whole, Span 80 has shown great potential in enhancing the HTC of swine manure. The acting mechanisms of surfactants in the HTC of swine manure included adsorption, dispersion, and electrostatics repulsion.

Catalyst-Enhancing Hydrothermal Carbonization of Biomass for Hydrochar and Liquid Fuel Production-A Review.

The research impact of catalysts on the hydrothermal carbonization (HTC) process remains an ongoing debate, especially regarding the quest to enhance biomass conversion into fuels and chemicals, which requires diverse catalysts to optimize bio-oil utilization. Comprehensive insights and standardized analytical methodologies are crucial for understanding HTC's potential benefits in terms of biomass conversion stages. This review seeks to understand how catalysts enhance the HTC of biomass for liquid fuel and hydrochar production, drawing from the following key sections: (a) catalyst types applied in HTC processes; (b) biochar functionality as a potential catalyst; (c) catalysts increasing the success of HTC process; and (d) catalyst's effect on the morphological and textural character of hydrochar. The performance of activated carbon would greatly increase via catalyst action, which would progress the degree of carbonization and surface modification, alongside key heteroatoms. As catalytic HTC technology advances, producing carbon materials for thermochemical activities will become more cost-effective, considering the ever-growing demands for high-performance thermochemical technologies.

KHCO3 Chemical-Activated Hydrothermal Porous Carbon Derived from Sugarcane bagasse for Supercapacitor Applications.

The reuse of waste biomass resources had become a hot topic in the sustainable development of human society. Biomass was an ideal precursor for preparing porous carbon. However, due to the complexity of biomass composition and microstructure, the quality reproducibility of biomass porous carbon was poor. Therefore, it was of great significance to develop a reliable method for preparing porous carbon from biomass. In this paper, The activated hydrothermal porous carbon was prepared by a combination of hydrothermal carbonization treatment and KHCO3 mild activation. The hydrothermal carbonization treatment could complete the morphology adjustment and iron doping of the carbon in one step, and the mild activation of KHCO3 could activate the porous carbon while maintaining the spherical morphology. Fe-modified porous carbon with carbon ball/nanosheet structure which facilitated ion/electrolyte diffusion and increased accessibility between surface area and electrolyte ions. Therefore, bagasse derived activated porous carbon had good specific capacitance (315.2 F/g at 1 A/g) and good cycle stability, with a capacitance loss of only 5.8% after 5000 charge-discharge cycles. This study showed that the combination of hydrothermal treatment and mild activation provided an effective way for the conversion of waste biomass into high-performance electrode materials.