Nitrogen-doped Porous Carbon Research Articles

Encapsulating Selenium into Biomass-Derived Nitrogen-Doped Porous Carbon As the Cathode for Sodium–Selenium and Potassium–Selenium Batteries

Encapsulating Selenium into Biomass-Derived Nitrogen-Doped Porous Carbon As the Cathode for Sodium–Selenium and Potassium–Selenium Batteries

High-Entropy Metal Nitride Embedded in Concave Porous Carbon Enabling Polysulfide Conversion in Lithium-Sulfur Batteries.

The practical implementation of lithium-sulfur batteries is severely hindered by the rapid capacity fading due to the solubility of the intermediate lithium polysulfides (LiPSs) and the sluggish redox kinetics. Herein, high-entropy metal nitride nanocrystals (HEMN) embedded within nitrogen-doped concave porous carbon (N-CPC) polyhedra are rationally designed as a sulfur host via a facile zeolitic imidazolate framework (ZIF)-driven adsorption-nitridation process toward this challenge. The configuration of high-entropy with incorporated metal manganese (Mn) and chromium (Cr)will optimize the d-band center of active sites with more electrons occupied in antibonding orbitals, thus promoting the adsorption and catalytic conversion of LiPSs. While the concave porous carbon not only accommodates the volume change upon the cycling processes but also physically confines and exposes active sites for accelerated sulfur redox reactions. As a result, the resultant HEMN/N-CPC composites-based sulfur cathode can deliver a high specific capacity of 1274 mAh g-1 at 0.2C and a low capacity decay rate of 0.044% after 1000 cycles at 1C. Moreover, upon sulfur loading of 5.0mg cm-2, the areal capacity of 5.0mAhcm-2 can still be achieved. The present work may provide a new avenue for the design of high-performance cathodes in Li-S batteries.

Nitrogen-Doped Porous Carbon with Staged Nanopore Formation for Capacitors

Nitrogen-Doped Porous Carbon with Staged Nanopore Formation for Capacitors

A novel 3D nitrogen-doped porous carbon supported Fe-Cu bimetallic nanoparticles composite derived from lignin: an efficient peroxymonosulfate activator for naphthalene degradation.

A novel 3D nitrogen-doped porous carbon supported Fe-Cu bimetallic nanoparticles composite (Fe-Cu-N-PC) was prepared via direct pyrolysis by employing black liquor lignin as a main precursor, and it was utilized as a novel catalyst for PMS activation in degrading naphthalene. Under the optimum experimental conditions, the naphthalene degradation rate was up to 93.2% within 60 min in the Fe-Cu-N-PC/PMS system. The porous carbon framework of Fe-Cu-N-PC could facilitate the quick molecule diffusion of reactants towards the inner bimetallic nanoparticles and enriched naphthalene molecules from the solution by a specific adsorption, which increased the odds of contact between naphthalene and reactive oxygen species and improved the reaction efficiency. The quenching reaction proved that the non-free radical pathway dominated by 1O2 was the main way in naphthalene degradation, while the free radical pathway involving SO4·- and ·OH only played a secondary role. Moreover, owing to its high magnetization performance, Fe-Cu-N-PC could be magnetically recovered and maintained excellent naphthalene degradation rate after four degradation cycles. This research will offer a theoretical basis for the construction of facile, efficient, and green technologies to remediate persistent organic pollutants in the environment.

FeCu bimetallic clusters for efficient urea production via coupling reduction of carbon dioxide and nitrate

Urea electrosynthesis has appeared to meet the nitrogen cycle and carbon neutrality with energy-saving features. Copper can co-electrocatalyze among CO2 and nitrogen species to generate urea, however developing effective electrocatalysts is still an obstacle. Here, we developed a nitrogen-doped porous carbon loaded with FeCu clusters that convert CO2 and NO3− into urea, with the highest Faradaic efficiency of 39.8 % and yield rate of 1024.6 μg h−1 mgcat.−1, under optimized ambient conditions, exceeding that at the Fe or Cu homogeneous sites. Furthermore, a favorable CN coupling pathway originates from *NHCO and *NHCONO two intermediates with lower free energy barriers on FeCu dual active sites are verified through in-situ Fourier transform infrared spectroscopy and theoretical calculations. This research might provide deep insights into coupling mechanisms and investigation of efficient catalysts for green urea production.

High nitrogen-doped porous carbon material from porous aromatic framework; an approach to bi-functional Metal-free electrocatalyst

This study successfully synthesized nitrogen-doped porous carbon materials through pyrolysis of the azo-bridged calix[4]resorcinarene porous aromatic framework. This was the first time that N was introduced into porous carbon materials by using the azo group (N = N) as a nitrogen source. Nitrogen-doped porous carbon materials (N-C-x) were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and nitrogen adsorption–desorption isotherms. The efficiency of the fabricated electrocatalysts was assessed toward oxygen reduction reaction (ORR) in whole-range pH and oxygen evolution reaction (OER) in the base media. N-C-900 displayed outstanding activity among the prepared samples. In the ORR, the onset potential for N-C-900 was 0.99 V, 0.925 V, and 0.98 V vs. RHE in base, natural, and acidic electrolytes, respectively, which were close to commercial Pt/C in the same electrolyte. In OER, the optimal catalyst N-C-900 had an overpotential of 220 mV and a Tafel slope of 212 mV.dec-1, similar to RuO2.

Concave single-atom Co nanozymes with densely edge-hosted active sites for highly sensitive immunoassay

Regulating the geometric and electronic structures of single-atom catalysts could promote the potential to improve their enzyme-like catalytic performance. Herein, we demonstrate that concave single-atom Co catalysts with edge-hosted and dense active Co-N4 sites incorporated in nitrogen-doped hierarchical porous carbon (H-Co SACs) can act as highly efficient oxidase mimics. In particular, the engineered H-Co SACs with dense active Co-N4 moieties in the edge sites were found to display 3.1 times higher catalytic activity than that of traditional intact Co single-atom catalysts (L-Co SACs). Combined experimental and theoretical simulations reveal that the geometric structure and the interactions between adjacent edge-hosted CoN4 sites synergistically affect the electronic structure of the Co single-atom nanozymes, resulting in strong oxygen adsorption/activation and low energy barrier of the rate-determining step (RDS) in the reaction process, which are demonstrated be more beneficial for the oxidase-like catalytic performance. As a proof-of-concept application, the H-Co SACs were applied to the colorimetric enzyme-linked immunosorbent assay (ELISA) of neuron specific enolase (NSE) with a detection limit of 5.19 pg/ mL, outperforming both the intact Co single-atom catalysts and standard commercial ELISA kits. The present study could not only highlight the significance of geometric structure and active sites density effect on their enzyme-like catalytic efficiency, but also broaden their practical clinical application range of nanozymes at the atomic level.

Preparation of grape branch-derived porous carbon by one-step blending and its multifunctional applications

In this study, an innovative methodology is presented for the rapid one-step synthesis of carbon materials with high specific surface area through doping and activation processes, utilizing ball milling techniques to reduce the particle size of the materials effectively and to achieve activation and doping. Nitrogen-doped grape branch carbon (NGBC) was characterized by abundant micro- and mesoporous structures with specific surface areas up to 1364 m2/g and high nitrogen content (atomic fraction of 4.89 %). At pH 8 and room temperature, NGBC showed excellent adsorption performance for malachite green (MG, a cationic dye) and reactive blue 19 (an anionic dye) with adsorption capacities of 409.91 mg/g and 213.36 mg/g, respectively, and the material can be reused several times. The analysis of adsorption kinetics revealed that multiple factors controlled the adsorption process of NGBC on MG, and the analysis of adsorption isotherms showed that the adsorption process was mainly monomolecular layer adsorption. Compared with the common carbon-based adsorbents for biomass currently available on the market, NGBC showed better adsorption efficacy, indicating its great potential for practical application. Further, when NGBC was applied to electrochemical performance tests as supercapacitor electrodes, the introduction of nitrogen significantly improved the specific capacitance and ion transport properties of the porous carbon material, effectively reducing the electrical resistance. At a current density of 0.5 A/g, the nitrogen-doped porous carbon showed a specific capacitance of 258.4 F/g, much higher than that of the undoped 136.8 F/g, as well as a high specific capacitance retention of 90.43 % after 5000 cycles. The sensitivity analysis points out that nitrogen source and labor expenditure are the key factors in the cost components. This research not only provides a simple method for industrialized recovery and reuse of grape branches, but also lays an experimental and theoretical foundation for promoting further applications of biomass waste in the fields of water purification and supercapacitor electrode materials.

Coupling of Fe-Nx sites and Fe nanoparticles on nitrogen-doped porous carbon for boosting oxygen electroreduction in Zn-air batteries

Fe and nitrogen co-doped carbon (Fe-N-C) catalysts have emerged as attractive materials to substitute Pt-based catalysts for the oxygen reduction reaction (ORR) in Zn-air batteries (ZABs). However, the Fe-N-C catalysts with monotypic active component usually endow suboptimal catalytic performance and stability under both acid and alkaline medium. Herein, a nano ZnO template and two-step pyrolysis co-assisted strategy is proposed to achieve the coupling of Fe-Nx sites and metallic Fe nanoparticles in hierarchically porous N-doped carbon for ORR. The nano ZnO template contributes to the formation of meso/macropores structure, while the secondary pyrolysis is beneficial to the creation of more micropores. Besides the advanced hierarchical porosity, the combination of dispersed Fe-Nx sites and dominated metallic Fe nanoparticles is also conducive to boost ORR activity in both acid and alkaline solution. Impressively, the prepared Fe@FeHPNC-P2 electrocatalyst exhibits an excellent half-wave potentials (E1/2) of 0.88 V and 0.79 V in alkaline and acidic electrolyte, respectively. Meanwhile, the assembled liquid Zn-air battery using Fe@FeHPNC-P2 delivers a peak power density of 149.3 mW cm−2 and a maximum energy density of 957.1 Wh kgZn−1 along with long-term stability for 1000 cycles.

Monitoring Poly(methyl methacrylate) and Polyvinyl Dichloride Micro/Nanoplastics in Water by Direct Solid-Phase Microextraction Coupled to Gas Chromatography-Mass Spectrometry.

A simple, sustainable, and sensitive monitoring approach of micro/nanoplastics (MNPs) in aqueous samples is crucial since it helps in assessing the extent of contamination and understanding the potential risks associated with their presence without causing additional stress to the environment. In this study, a novel strategy for qualitative and quantitative determination of MNPs in water by direct solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was proposed for the first time. Spherical poly(methyl methacrylate) (PMMA) and irregularly shaped polyvinyl dichloride (PVDC) were used to evaluate the feasibility and performance of the proposed method. The results demonstrated that both PMMA and PVDC MNPs were efficiently extracted by the homemade SPME coating of nitrogen-doped porous carbons (N-SPCs) and exhibited sufficient thermal decomposition in the GC-MS injection port. Excellent extraction performances of N-SPCs coating for MNPs are attributed to hydrophobic cross-linking, electrostatic forcing, hydrogen bonding, and pore trapping. Methyl methacrylate was identified as the marker for PMMA, while 1,3-dichlorobenzene and 1,3,5-trichlorobenzene were the indicators for PVDC. Under the optimal extraction and decomposition conditions, the proposed method exhibited ultrahigh sensitivity, with a limit of detection of 0.0041 μg/L for PMMA and 0.0054 μg/L for PVDC. Notably, a programmed temperature strategy for the GC-MS injector was developed to discriminate and eliminate the potential interferences of intrinsic indicator compounds. Owing to the integration of sampling, extraction, injection, and decomposition into one step by SPME, the proposed method demonstrates exceptional sensitivity, eliminating the necessity for complex sample pretreatment procedures and the use of organic solvents. Finally, the proposed method was successfully applied in the determination of PMMA and PVDC MNPs in real aqueous samples.

Adjustable nanoarchitectonics of N-doping Yolk-Shell carbon spheres via “Pyrolysis-Capture” method for High-Performance supercapacitor

The energy storage capacity of porous carbon materials is closely tied to their surface structure and chemical properties. However, developing an innovative and straightforward approach to synthesize yolk-shell carbon spheres (YCs) remains a great challenge till date. Herein, we prepared a series of porous nitrogen-doped yolk-shell carbon spheres (NYCs) via a “pyrolysis-capture” method. This method involves coating the resorcinol–formaldehyde (RF) resin sphere with a layer of compact silica shell induced by 2-methylimidazole (ME) catalysis to produce a confined nano-space. Based on the confined effect of compact silica shell, volatile gases emitted from the RF resin and ME during pyrolysis can not only diffuse into the pores of the RF resin but can also be captured to form an outer carbon shell. This results in the tunable structures of NYCs materials. As the pyrolysis temperature rises, the shell thickness of NYCs reduces, the pore size expands, the roughness increases, and the N/O content of surface elements is enhanced. Notably, as an electrode material used forsupercapacitors,the optimized NYCs-800 exhibits excellent performance with a capacitance of 301.2F g−1 at the current density of 1 A/g and outstanding cycling life stability of 96.1% after 10,000 cycles. These results signify that controlling the surface structure and chemical properties of NYCs materials is an effective approach for constructing advanced energy storage materials.

A Sustainable and Cost-Effective Nitrogen-Doped Three-Dimensional Porous Carbon for High-Performance Lithium-Sulfur Batteries.

Affordable clean energy is one of the major sustainable development goals that can transform our world. At present, researchers are working to develop cheap electrode materials to develop energy storage devices, the Lithium-sulfur (Li-S) battery is considered a promising energy storage device owing to its excellent theoretical specific capacity and energy density. Herein, utilizing the ramie degumming waste liquid as raw materials, after freeze-drying and high-temperature calcination, a sustainable and cost-effective three-dimensional (3D) porous nitrogen-doped ramie carbon (N-RC) was synthesized. The N-RC calcined at 800 °C (N-RC-800) shows a superior high specific surface area of 1491.85 m2 ⋅ g-1 and a notable high pore volume of 0.90 cm3 ⋅ g-1. When employed as a sulfur host, the S@N-RC-800 cathode illustrates excellent initial discharge capacity (1120.6 mAh ⋅ g-1) and maintains a reversible capacity of 625.4 mAh ⋅ g-1 after 500 cycles at 1 C. Simultaneously, the S@N-RC-800 cathode also shows excellent coulombic efficiency and ideal rate performance. Such exceptional electrochemical performance of S@N-RC-800 can be primarily attributable to N-RC's high specific surface area, high porosity, and abundant polar functional groups. This green and low-cost synthesis strategy offers a new avenue for harnessing the potential of waste biomass in the context of clean energy storage.

Empowering green sustainable technologies: Frontier synthesis of oxygen vacancy-modified cobalt oxide

The electrocatalytic hydrogen production and supercapacitor technologies have positive impacts on the environment, promoting the production and utilization of clean and renewable energy sources, thus facilitating the reduction of greenhouse gas emissions. Among them, cobalt oxide (Co3O4) has emerged as an ideal choice for electrode materials in these technologies due to its low toxicity, affordability, and significant theoretical capacity. Nevertheless, practical applications are restricted by its low conductivity and sluggish reaction kinetics. Addressing these challenges, this study introduces a pioneering approach: the synthesis of oxygen vacancy-modified Co3O4/Co/NC small-sized nanoflower composite, which combines the advantages of abundant oxygen vacancies, small size effects, and nitrogen-doped porous carbon. The optimized Co3O4/Co/NC small-sized nanoflower exhibits high porosity and excellent conductivity, providing numerous active sites and effectively enhancing the ion and electron transport rates. As a consequence, optimized Co3O4/Co/NC shows a low Tafel slope and overpotential, highlighting its potential for catalytic application. Moreover, as an electrode for supercapacitors, optimized Co3O4/Co/NC demonstrates excellent long-term stability, maintaining 94.7% of its capacitance even after 5000 charge-discharge cycles. Additionally, it showed a significant specific capacity of 251.4 mAh g−1 when tested at 1 A g−1. In addition to addressing the pressing challenges associated with traditional Co3O4 electrodes, this work opens up exciting avenues for designing and fabricating transition metal oxide-based materials with unprecedented electrochemical performance.

Repairable body-centered cubic Fe0 anchoring on porous hollow nitrogen-doped carbon spheres with adjusting electron distribution for efficient electrocatalytic ammonia synthesis

Electrocatalytic nitrogen reduction reaction (ENRR) is a promising and efficient method for ammonia production. However, ENRR is restricted by the adsorption and activation of N2. Herein, an efficient nitrogen reduction reaction (NRR) electrocatalyst loaded with zero valent iron (ZVI) particles onto porous nitrogen-doped carbon (NC) hollow spheres is reported. The optimal Fe@10N3C-950 exhibits excellent performance with high ammonia (NH3) yield (152.28 µg h−1 mgcat−1) and Faradaic efficiency (FE, 54.55 %) at − 0.3 V (versus reversible hydrogen electrode, vs. RHE). Bader charge shows that the adsorbed N2 acquires more electrons from Fe sites with body-centered cubic (BCC) structure to better activate N2. Moreover, i-t experiments are performed before electrocatalytic NH3 production to effectively eliminate the effect of oxidation on ZVI and thus, maintain high ENRR activity for Fe@10N3C-950. Theoretical calculations indicate that nitrogen doping not only reduces the Gibbs free energy of rate determining step (RDS), but the BCC-structured Fe can also decrease the energy barriers of N2 activation and RDS.

Preparation of nitrogen-doped porous carbon from pyrolysis of light bio-oil pretreated poplar powder and its electrochemical performance

Biomass are widely used for the preparation of porous carbon materials (PCM). Therefore, there is considerable interest in how to obtain PCM with excellent electrochemical performance from biomass. Effective pretreatment methods can significantly improve the electrochemical performance of PCM. However, the low nitrogen content in most biomass limits its further application as electrode materials. Thus, this paper proposes a new method for preparing nitrogen-doped PCM. Nitrogen-doped PCM with outstanding performance were synthesized from poplar powder pretreated by light bio-oil in a ZnCl2/urea system. The findings indicate that adding urea notably enhanced nitrogen content in PCM surface, improving its electrochemical performance. When the mass ratio of ZnCl2, pretreated poplar powder and urea is 2:1:1 (PZN1-500), the nitrogen content of prepared PCM is 9.46 %. The maximum specific capacitance reaches 382.7 F/g at 0.5 A/g. Furthermore, the assembled symmetrical PZN1-500 supercapacitor possessed the energy density of 9.16 Wh kg−1 at 125 W kg−1 with the capacitance retention of 92.65 % after 10,000 cycles. The preparation strategy of nitrogen-doped PCM proposed in this study is helpful for the further development of supercapacitors and the high-value utilization of biomass.

Iron-Cobalt Nanoparticles Embedded in B,N-Doped Chitosan-Derived Porous Carbon Aerogel for Overall Water Splitting.

Given their intriguing properties, porous carbons have surfaced as promising electrocatalysts for various energy conversion reactions. This study presents a unique approach where iron-cobalt (FeCo) is confined in a boron, nitrogen-doped chitosan-derived porous carbon aerogel (BNPC-FeCo) to serve as an electrocatalyst for the hydrogen evolution and oxygen evolution reactions (HER and OER). The BNPC-FeCo-900 electrocatalyst demonstrates excellent catalyst activity, with very low overpotentials of 186 and 320 mV at 10 mA cm-2, low Tafel slopes of 82 and 55 mV dec-1, and low charge transfer resistance of 2.68 and 9.25 Ω for HER and OER, respectively. Density functional theory (DFT) calculations further reveal that the cooperation between the boron, nitrogen codoped porous carbon, and the FeCo nanoparticles reduces intermediates' energy barriers, significantly enhancing the HER and OER performance. In conclusion, this work offers significant and informative perspectives into the potential of porous carbon materials as dual-purpose electrocatalysts for water splitting.

Accelerated Conversion of Polysulfides for Ultra Long-Cycleof Li-S Batteryat High-Rateover Cooperative Cathode Electrocatalystof Ni0.261Co0.739S2/N-Doped CNTs.

Despite the very high theoretical energy density, Li-S batteries still need to fundamentally overcome the sluggish redox kinetics of lithium polysulfides (LiPSs) and low sulfur utilization that limit the practical applications. Here, highly active and stable cathode, nitrogen-doped porous carbon nanotubes (NPCTs) decorated with NixCo1-xS2 nanocrystals are systematically synthesized as multi-functional electrocatalytic materials. The nitrogen-doped carbon matrix can contribute to the adsorption of LiPSs on heteroatom active sites with buffering space. Also, both experimental and computation-based theoretical analyses validate the electrocatalytic principles of co-operational facilitated redox reaction dominated by covalent-site-dependent mechanism; the favorable adsorption-interaction and electrocatalytic conversion of LiPSs take place subsequently by weakening sulfur-bond strength on the catalytic NiOh 2+-S-CoOh 2+ backbones via octahedral TM-S (TM = Ni, Co) covalency-relationship, demonstrating that fine tuning of CoOh 2+ sites by NiOh 2+ substitution effectively modulates the binding energies of LiPSs on the NixCo1-xS2@NPCTs surface. Noteworthy, the Ni0.261Co0.739S2@NPCTs catalyst shows great cyclic stability with a capacity of up to 511 mAh g-1 and only 0.055% decay per cycle at 5.0 C during 1000 cycles together with a high areal capacity of 2.20 mAh cm-2 under 4.61mg cm-2 sulfur loading even after 200 cycles at 0.2 C. This strategy highlights a new perspective for achieving high-energy-density Li-S batteries.

Encapsulation of ruthenium oxide nanoparticles in nitrogen-doped porous carbon polyhedral for pH-universal hydrogen evolution electrocatalysis

The development of pH-universal HER electrocatalyst with Pt-like activity remains challenged yet critical for hydrogen energy systems. Herein, we have successfully immobilized RuOx nanoparticles on the surface of C–N derived from zeolitic imidazolate frameworks (RuOx@C–N). The obtained RuOx@C–N exhibits Pt-like HER performance with overpotential of as low as 14 and 93 mV to drive the current density of −10 and −100 mA cm−2 in 1.0 M KOH, respectively. Furthermore, RuOx@C–N exhibits an unexpected mass activity of 0.81 A cm−2 mgRuOx−1, which is even superior to benchmark Pt/C. Such an improvement is attributed to RuOx@C–N heterostructure, which will facilitate the electron transfer due to the Mott-Schottky effect. Additionally, the nitrogen-doped carbon framework will efficiently adjust the electronic structure of metallic catalytic sites and optimize the kinetics of catalytic reaction. Benefiting from the Mott-Schottky effect, the RuOx@C–N electrocatalysts exhibit pH-universal catalytic performance toward hydrogen evolution in various electrolytes, corroborating its university and facility in industrial hydrogen production. This approach offers a facile and versatile strategy for the development of Ru-based electrocatalysts with high performance and robust stability.

Atomically dispersed copper-zinc dual sites anchored on nitrogen-doped porous carbon toward peroxymonosulfate activation for degradation of various organic contaminants

Single-atom catalysts (SACs) have been widely studied in Fenton-like reactions, wherein their catalytic performance could be further enhanced by adjusting electronic structure and regulating coordination environment, although relevant research is rarely reported. This text elucidates fabrication of dual atom catalyst systems aimed at augmenting their catalytic efficiency. Herein, atomically dispersed copper-zinc (Cu-Zn) dual sites anchored on nitrogen (N)-doped porous carbon (NC), referred to as CuZn-NC, were synthesized using cage-encapsulated pyrolysis and host–guest strategies. The CuZn-NC catalyst exhibited high activity in activation of peroxymonosulfate (PMS) for degradation of organic pollutants. Based on synergistic effects of adjacent Cu and Zn atom pairs, CuZn-NC (PMS) system achieved 94.44 % bisphenol A (BPA) degradation in 24 min. The radical pathway predominated, and coexistence of non-radical species was demonstrated for BPA degradation in CuZn-NC/PMS system. More importantly, CuZn-NC/PMS system showed generality for degradation of various refractory contaminants. Our experiments indicate that CuZn-N sites on CuZn-NC act as active sites for bonding PMS molecules with optimal binding energy, while pyrrolic N sites are considered as adsorption sites for organic molecules. Overall, this research designs diatomic site catalysts (DACs), with promising implications for wastewater treatment.

Eco-friendly preparation of nitrogen-doped porous carbon materials for enhanced solid-state supercapacitor device

In the last years, researchers all over the world have been looking for biomass-derived porous carbon materials, due to the possibilities for large-scale synthesis, easy to control the pore structure, and high specific surface area. Activated heteroatom doped porous carbon (AHPC) with a high porosity was made by treating inexpensive waste Ficus elastica leaves with a base. The electrochemical performance of the produced activated carbon has been evaluated in various electrolytes, including basic, neutral, and acidic electrolytes. At a current density of 1 A/g in the acidic electrolyte, the specific capacitance of the activated carbon AHPC electrode is higher, 456 F/g, compared to other electrolytes. The symmetric supercapacitor device is built using PVA-H2SO4 gel electrolyte, and its electrochemical performance is evaluated. In addition, the energy density of the built symmetric supercapacitor device is higher than the existing commercial supercapacitors, achieving 62 Wh/kg at a power density of 15.2 kW/kg. This is because the porous carbon has a hierarchical pore distribution and a heteroatom-enriched structure, which allows for rapid charge/mass diffusion channels, and a vast ion-accessible network.