1M KOH Research Articles

RuCu Nanorod Arrays Synergistically Promote Efficient Water-Splitting

In the realm of green hydrogen energy, utilizing ruthenium (Ru) as a precious metal electrocatalyst for the hydrogen evolution reaction (HER) instead of platinum (Pt/C) is an excellent choice. Unfortunately, there are not enough active sites or electronic structures on a single Ru-based catalyst to significantly improve the oxygen evolution reaction (OER). Therefore, creating bifunctional water electrolysis catalysts that are stable and highly active in a variety of media continues to be a major challenge. The study describes a new method for creating an electrocatalyst (RuCuCl/NF-2) by using Ru to regulate an inert CuCl precursor. The enhanced mass transfer performance of the distinctive coral structure and the synergistic effect of RuCu emphasize its excellent water electrolysis activity, which is based on the self-assembly of Cu nanoparticles into a conical membrane structure. Overtaking the commercial benchmark Pt/C (~38 mV to reach 10 mA cm−2), the RuCuCl/NF-2 displays HER activity (~25 mV to reach 10 mA cm−2) in 1M KOH. This sheds light on how to create more sophisticated bifunctional electrocatalysts.

Cerium oxide nanoparticles decorated on graphene oxide nanosheets as battery-type cathode material for supercapacitors.

Designing advanced materials that effectively mitigate the poor cycle life of battery-type electrodes with high specific capacities is crucial for next-generation energy storage systems. Herein, graphene oxide-ceria (GO-CeO2) nanocomposite synthesized via a facile wet chemical route is explored as cathode for high-performance supercapacitors. The morphological analysis suggests fine ceria (CeO2) nanoparticles dispersed over ultrathin graphene oxide (GO) sheets while structural studies reveal face-centered cubic phase of CeO2 in the nanocomposite. In-depth electrochemical performance investigation of the nanocomposite in 6M KOH aqueous electrolyte demonstrated its excellent battery-type behavior with least ion diffusion resistance and a superior cycle life resulting from the synergistic effect of redox-active CeO2 and 2D GO with abundant oxygen functionalities. Specifically, GO-CeO2 composite electrode delivered a maximum specific capacitance of 625.9F/g (52.2mAh/g) at 3 A/g current density, which is substantially higher than the capacitance values obtained for GO and CeO2 electrodes, and demonstrated an excellent cycling stability with∼100% capacitance retention after 10,000 CV cycles. Furthermore, a novel aqueous asymmetric supercapacitor (ASC) is explored with GO-CeO2 as positive and iron(III) oxyhydroxide (FeOOH) as negative electrode material in 6M KOH electrolyte which has also displayed good energy-power density combination along with excellent cycle stability. The study thus endorses rational design of nanocomposite materials with suitable functionalities as an excellent strategy in augmenting the performance of futuristic energy storage devices.

Rapid Synthesis of Carbon-Supported Ru-RuO₂ Heterostructures for Efficient Electrochemical Water Splitting.

Development of high-performance electrocatalysts for water splitting is crucial for a sustainable hydrogen economy. In this study, rapid heating of ruthenium(III) acetylacetonate by magnetic induction heating (MIH) leads to the one-step production of Ru-RuO₂/C nanocomposites composed of closely integrated Ru and RuO₂ nanoparticles. The formation of Mott-Schottky heterojunctions significantly enhances charge transfer across the Ru-RuO2 interface leading to remarkable electrocatalytic activities toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1m KOH. Among the series, the sample prepares at 300 A for 10 s exhibits the best performance, with an overpotential of only -31mV for HER and +240mV for OER to reach the current density of 10mA cm⁻2. Additionally, the catalyst demonstrates excellent durability, with minimal impacts of electrolyte salinity. With the sample as the bifunctional catalysts for overall water splitting, an ultralow cell voltage of 1.43V is needed to reach 10mA cm⁻2, 160mV lower than that with a commercial 20% Pt/C and RuO₂/C mixture. These results highlight the significant potential of MIH in the ultrafast synthesis of high-performance catalysts for electrochemical water splitting and sustainable hydrogen production from seawater.

Self-Reconstruction of High Entropy Alloys for Efficient Alkaline Hydrogen Evolution.

Alkaline water (H2O) electrolysis is currently a commercialized green hydrogen (H2) production technology, yet the unsatisfactory hydrogen evolution reaction (HER) performance severely limits its energy conversion efficiency and cost reduction. Herein, PtRu2.9Fe0.15Co1.5Ni1.3 high entropy alloys (HEAs) is synthesized and subsequently exploited electrochemically induced structural oxidation processes to construct self-reconfigurable HEAs, as an efficient alkaline HER catalyst. The optimized self-reconstructed PtRu2.9Fe0.15Co1.5Ni1.3 HEAs with the HEAs and cobalt rutheniate interface (HEAs-Co2RuO4) exhibits excellent alkaline HER performance, requiring just 11.8mV to obtain a current density (j) of 10 mA cm-2 in 1m KOH. And the j on HEAs-Co2RuO4 is 41.8 mA cm-2 at 0.07 VRHE, 2.0 and 6.1 times higher than PtRu2.9Fe0.15Co1.5Ni1.3 HEAs and 20% Pt/C. Mechanism studies reveal that the improved alkaline HER performance of HEAs-Co2RuO4 is due to the formation of HEAs-Co2RuO4, which significantly shrinks the Helmholtz layer, provides a new fast material transport channel, boosts H2O adsorption, and reduces hydrogen adsorption, and thus accelerates the alkaline HER. This research not only throws new light on the self-reconstruction of catalysts but also provides guidance for the rational design of efficient electrocatalysts.

Tuning Hydrogen Binding on Ru Sites by Ni Alloying on MoO2 Enables Efficient Alkaline Hydrogen Evolution for Anion Exchange Membrane Water Electrolysis.

Ruthenium (Ru)-based electrocatalysts have shown promise for anion exchange membrane water electrolysis (AEMWE) due to their ability to facilitate water dissociation in the hydrogen evolution reaction (HER). However, their performance is limited by strong hydrogen binding, which hinders hydrogen desorption and water re-adsorption. This study reports the development of RuNi nanoalloys supported on MoO2, which optimize the hydrogen binding strength at Ru sites through modulation by adjacent Ni atoms. Theoretical simulations reveal that substituting Ni atoms for adjacent Ru atoms reduces the high hydrogen adsorption Gibbs free energy on Ru while maintaining a low energy barrier for water dissociation. As a result, the RuNi/MoO₂ catalyst shows excellent HER performance with a low overpotential of 51mV at a current density of 100mAcm⁻2, outperforming commercial Pt/C. Furthermore, RuNi/MoO₂ demonstrates high turnover frequency (7.06s-1), mass activity (13.4Amg-1), and price activity (1030.77Adollar-1). In an AEMWE cell, RuNi/MoO₂ as the cathode catalyst achieves a current density of 1Acm-2 at 60°C with just 1.7V using 1m KOH. This work highlights the potential of RuNi/MoO₂ for ultra-high mass activity in efficient AEMWE applications.

Lattice Strain-Modulated Trifunctional CoMoO4 Polymorph-Based Electrodes for Asymmetric Supercapacitors and Self-Powered Water Splitting.

Developing efficient, multifunctional electrodes for energy storage and conversion devices is crucial. Herein, lattice strains are reported in the β-phase polymorph of CoMoO4 within CoMoO4@Co3O4 heterostructure via phosphorus doping (P-CoMoO4@Co3O4) and used as a high-performance trifunctional electrode for supercapacitors (SCs), hydrogen evolution reaction (HER), and oxygen evolution reaction (OER) in alkaline electrolytes. A tensile strain of +2.42% on the β-phase of CoMoO4 in P-CoMoO4@Co3O4 results in superior electrochemical performance compared to CoMoO4@Co3O4. The optimized P-CoMoO4@Co3O4 achieves a high energy density of 118Wh kg-1 in an asymmetric supercapacitor and low overpotentials of 189mV for the HER and 365mV for the OER at a current density of 500mA cm-2. This results in a low overall water splitting voltage of 1.71V at the same current density making it an effective bifunctional electrode in a 1m KOH freshwater electrolyte. Theoretical analysis shows that the excellent performance of P-CoMoO4@Co3O4 can be attributed to interfacial interactions between CoMoO4 and Co3O4, and the β-phase of CoMoO4, which lead to strong OH- adsorption and low energy barriers for reaction intermediates. Practical application is demonstrated by using P-CoMoO4@Co3O4-based ASCs to self-generate hydrogen (H2) in a P-CoMoO4@Co3O4||P-CoMoO4@Co3O4 alkaline seawater electrolyzer, showcasing its potential for future energy technologies.

Corrosion Behaviour of Cu-Plate Current Collector under Ex-situ Cyclic Stability Testing for Energy Storage Application

This study compares the corrosion behaviour of a copper plate current collector subjected to an ex-situ cyclic stability test in a 6M KOH and a 6M Na2SO4 electrolyte solution for an electrochemical supercapacitor cell. Through experimental analysis, the change in microstructures resulting from the corrosion behaviour of the copper plate current collector samples are examined by employing various analytical techniques, including microscopy, spectroscopy, and surface roughness analyzer. The corrosion behaviour was studied by employing potentiodynamic polarization and electrochemical impedance spectroscopy analyses. The copper plate current collector samples analysed in 6M KOH and 6M Na2SO4 electrolyte solution showed uniform and localized corrosion product formation, respectively. The CU-72HRS sample recorded a corrosion potential of -608.6mV, -628.87mV, and -89.5mV, -87.588mV using both Tafel and resistance polarization data fitting analysis, respectively, for both 6M KOH and 6M Na2SO4 electrolyte solution using a scan rate of 5mV/s at a voltage window of -1 to 1V. Comparing the microstructural changes under various cyclic conditions provides valuable insights into the durability and reliability of copper plates as current collectors in energy storage systems. The results of this study help improve our understanding of the supercapacitor cell performance in ex-situ cyclic stability tests, assisting in the development of more efficient and durable energy storage technologies.

Construction of core-shell NiFe LDH/Co(OH)F amorphous/crystalline heterostructure for synergistically enhanced electrocatalytic water oxidation

The development of high performance non-precious transition metal electrocatalysts for the oxygen evolution reaction (OER) is essential for the practical application of electrocatalytic water splitting. A promising strategy to prepare highly efficient and stable electrocatalysts for the OER can be achieved by constructing heterointerfaces between the amorphous and crystalline phases. Herein, a novel three-dimensional (3D) core-shell structured NiFe-LDH/Co(OH)F electrocatalyst on nickel foam (NF) with an amorphous/crystalline interface was achieved by growing 2D amorphous NiFe LDH nanosheets onto 1D crystalline Co(OH)F nanorod arrays using a simple two-step hydrothermal method. The resulting NiFe LDH/Co(OH)F/NF electrode exhibits outstanding electrochemical OER performance with an overpotential of 202 and 260mV at the current density of 10 and 100mAcm-2, a Tafel slope of 44.06mV dec-1, and an ultra-high stability over 100h at 300mAcm-2 without obvious degradation in 1M KOH. This research affords a new way to construct high-performance 3D hierarchical non-noble metal electrocatalysts for OER.

Homologous metal-organic complexes reconstructed oxy-hydroxide heterostructures as efficient oxygen evolution electrocatalysts.

It is imperative to investigate more cost-effective, long-lasting, efficient, and reliable non-noble metal electrocatalysts for the oxygen evolution reaction (OER) in hydrogen production via water splitting. Metal-organic complexes have been extensively researched and utilized for this purpose, yet their transformation in this process remains intriguing and underexplored. To enable a comprehensive comparison, we synthesized three types of metal-organic complexes with varying morphologies using the same raw material. Specifically, monocrystalline and lamella Fe-Co metal-organic frameworks (MOFs), along with Fe-Co metal-organic gels (MOGs), were created using p-Phthalic acid (PTA) as a ligand to facilitate the oxygen evolution reaction in a 1M KOH solution. The overpotential (η10) of MOF nanosheets (MOF-NSs) was 286mV at 10mAcm-2 under 1M KOH, while that of MOGs was 297mV, and MOF single crystals (MOF-SCs) exhibited an overpotential (η10) of 346mV. Density-functional theory (DFT) calculations demonstrated that the formation of FeOOH/CoOOH heterostructures reduced adsorption energy barriers and accelerated the rate-determining step, thereby improving the overall catalytic performance of OER. Hence, the structural reconstruction approach can be leveraged to develop and fabricate high-performance OER electrocatalysts in energy and related applications.

Partially Substituted La for Sm in Sm0.8Sr0.2NiO3: An Efficient Electrocatalyst Towards Alkaline Water Splitting

AbstractPerovskite‐type oxides having composition LaxSm0.8−xSr0.2NiO3 (0 ≤ x ≤ 0.6) were explored for their ability to act as facilitators for oxygen evolution reaction (OER) in alkaline media. Synthesis of the materials was conducted through a sol‐gel procedure via malic acid. The materials underwent advanced physicochemical characterization utilizing techniques, namely transmission electron microscope (TEM), scanning electron microscope/energy dispersive X‐ray spectroscopy (SEM/EDS), inductively coupled plasma – mass spectrometry (ICP‐MS) and X‐ray diffraction (XRD). These analyses provided crucial details about the material’s particle size, surface morphology/chemical composition and crystalline structure, opening up exciting possibilities for their diverse applications. From TEM analysis, the average particle size of the oxide materials has been estimated and found to be 5.9 nm for Sm0.8Sr0.2NiO3 and 4.8 nm for La0.6Sm0.2Sr0.2NiO3. The particle size of the oxide material decreases when La was partially substituted for Sm in Sm0.8Sr0.2NiO3. Cyclic voltammetry and Tafel plot were observed for the electrochemical analysis in 1 M KOH (25 °C). An investigation on the anodic polarization of oxides revealed an increased electrocatalytic activity when La was partially substituted for Sm in Sm0.8Sr0.2NiO3. La0.6Sm0.2Sr0.2NiO3 was found to be most active at 800 mV with a current density, j = 184.1 mA/cm2. The Tafel experiment was conducted in 1M KOH at varying temperatures to determine thermodynamic properties like standard electrochemical energy of activation (), standard enthalpy of activation (ΔH°#), and standard entropy of activation (ΔS°#).

EXTRACTION OF THE HUMIC-LIKE SUBSTANCES FROM COFFEE HUSK-DERIVED BIOCHAR: DETERMINE PARAMETERS OF EXTRACT PROCESS

Dissolved organic carbon (DOC) with a humic acid-like composition is a very important component of biochar in agricultural production applications. DOC extraction from biochar derived from coffee husks at different pyrolysis temperatures using a KOH solution was performed. The investigated parameters of the DOC extraction process included biochar pyrolysis temperature (300, 450, and 600℃), KOH content (0.5; 1.0 and 2.0 M), homogenization speed (4000, 6000, and 8000 rpm), extraction time (1, 2 and 3h) and biochar dosage used (50, 100 and 150 g/L). The optimal extraction process parameters were determined based on the DOC extraction efficiency and the contribution of humic acid-like substances. The results showed that the optimal extraction parameters selected were biochar pyrolyzed at 300℃, 2M KOH; homogenization speed of 6000 rpm, extraction time of 2 h, and biochar dosage of 100 g/L. The DOC extraction efficiency reached 33.7% and the main components of DOC were the humic-like substance with high molecular weight. The findings in this study not only determine the optimal parameters for the extraction of organic matter from biochar but also provide a theoretical basis for the use of biochar-based extracts as liquid organic fertilizers or soil conditioners.

Facile green synthesis of silver doped NiO nanoparticles using aloe vera latex for efficient energy storage and photocatalytic applications.

Herein, we report the biosynthesis of pure NiO and NiO nanoparticles doped with Silver (Ag@NiO NPs) 2, 4, 6, and 8mol% from aloe vera extract by solution combustion method at 400°C and calcined at 500°C for 3h. By utilizing silver-doped NiO nanoparticles synthesized with Aloe Vera latex, which not only enhances the material's properties but also promotes environmentally friendly fabrication methods. The morphological, structural elemental compositions were analysed through SEM, HRTEM, SAED, XRD and EDAX. The band gap was determined as 2.48, 2.57, 2.58, 2.60, and 2.62eV for pure NiO, 2-8% Silver doped NiO using Kubelka-Munk plot. The photocatalytic potential of the 6% Ag doped NiO has been explored by assessing their effectiveness in degrading fast blue (FB) dye, demonstrating significant activity at 605nm. Remarkably, with 120min of UV radiation, the FB dye reaches an impressive photodegradation rate of 98 %, making the dye nearly colorless. The green synthesized NPs were tested in 1M KOH to investigate their supercapacitor performance as an effective material for electrode. The Cyclic Voltammetry (CV), the Galvanostatic charge-discharge (GCD), and the Electrochemical impedance spectroscopy (EIS) studies were conducted to determine the materials' electrochemical activity. The GCD study for 6mol% Ag@NiO in a 3-electrode system shows a capacitance of 535Fg-1 at a current density of 1 Ag-1. 6mol% Ag@NiO modified electrode shows excellent long-term stability, retention of more than 92% of its initial capacitance after the operation of 2000 cycles. The important outcome of this work lies in multifunctional application of the as-synthesized materials, demonstrating their effectiveness for both efficient energy storage and improved photocatalytic performance, paving the way for sustainable and multifunctional devices.

Corrosion Behavior of Zinc/Polyaniline Composites as an Anode for Zn-air Batteries in 6M KOH

Corrosion Behavior of Zinc/Polyaniline Composites as an Anode for Zn-air Batteries in 6M KOH

Stabilizing Polyoxometalate for Enhanced OER Performance Using a Porous Manganese Oxide Support.

The oxygen evolution reaction (OER) is a critical challenge in electrocatalytic water splitting, hindered by high energy demands and slow kinetics. Polyoxometalates (POMs), recognized for their unique redox capabilities, structural archetypes, and molecular precision, are promising candidates for the oxygen evolution reaction (OER). Yet, their application is hindered by high water solubility, causing rapid degradation and efficiency loss under harsh OER conditions. This study enhances the performance and stability of polyoxometalates (POMs) for OER by anchoring keggin-type POM [TiCoW11O40]7- nanosheets onto a conductive, carbon-protected manganese oxide (C-Mn2O3) nanospheres support. The acquired porous framework enhances POM/C-Mn2O3 (PCM) contact, improving stability, reaction kinetics, and redox activity by offering nucleation sites, electronic pathways, and abundant active sites, significantly boosting OER activity. The resulting PCM nanohybrid demonstrates remarkable OER activity in 1M KOH, requiring only a 300 mV overpotential to achieve a current density of 10 mA cm-2 with a Tafel slope of 88 mV/dec. The PCM electrocatalyst also shows high mass activity (784 A/g at 1.6 V) and maintains stability over 100 hours at 100 mA cm-2 without performance fatigue. Consequently, this study offers a viable strategy for developing efficient, durable electrocatalysts using low-cost materials.

Probing Photo-Assisted Charge Storage Mechanism Using Bi-Fe Perovskite Oxide Electrode for Solar Supercapacitor.

In this study, the rhombohedral crystalline pure phase BiFeO3 (BFO) of irregularly shaped spherical particles of ≈100 nm and energy bandgap of ≈2.31 eV are synthesized by sol-gel auto-combustion method and explored as electrode material for photo-assisted supercapacitor. The electronic structure studies revealed that the coexistence of heterovalent Bi and Fe elements accelerated the electrochemical redox kinetics and photo-assisted charge storage properties. The resonant photoemission studies confirmed that near the Fermi level, the valence band spectra comprised the Fe3d and O2p hybridized states. The Fe-O hybridized state felicitates the charge transfer transitions (O2p (h+) + hυ ↔ Fe3+ + e- ↔ Fe2+), which assists the intercalation/de-intercalation process of OH- anions. Therefore, BFO has delivered 26.77% photo efficiency and the enhanced specific capacity of 21 Cg-1 at 2 Ag-1 in aq. 3m KOH under illumination, which is attributed to the accelerated photo-generated charge carrier separation and storage with surface polarization effect. BFO also delivered capacitance retention of 77.5% even after 1000 continuous GCD cycles under visible light irradiation.

PtNi nanorods catalysts prepared by magnetron sputtering for alkaline hydrogen evolution reaction

The development of cost‐effective and highly efficient catalysts for the hydrogen evolution reaction (HER), particularly in alkaline environments, is a critical challenge for hydrogen applications. One promising approach involves the alloying of noble metals with transition metals. This study presents the synthesis of PtNi nanorod catalysts, characterized by a thickness of 500 nm, which were fabricated via magnetron sputtering onto nickel foam. When evaluated in a 1M KOH electrolyte, the Pt‐Ni alloy demonstrates superior HER performance compared with both Ni and Pt, exhibiting an overpotential of 35 mV at 10 mA/cm² and a Tafel slope of 29 mV/dec. The enhanced catalytic activity is attributed to several factors, including a high electrochemically active surface area, increased mass activity, elevated turnover frequency, and reduced electrochemical impedance. Furthermore, the Pt‐Ni catalyst maintains remarkable stability at a current density of 10 mA/cm² over a duration of 100 hours. The improved HER performance is ascribed to the nanorod architecture, which features a high density of grain boundaries, as well as the synergistic interactions between Ni and Pt.

Smart Compositional Design of B-Site Ordered Double Perovskite for Advanced Oxygen Catalysis at Ultra-High Current Densities.

Perovskite oxides have been considered promising oxygen catalysts foroxygen reduction and evolution reactions (ORR and OER), owing to structural and compositional flexibility, and tailorable properties. Ingenious B-site ordered La1.5Sr0.5NiMn0.5Fe0.5O6 (LSNMF) double perovskite is strategically designed by simultaneously interposing Ni0.5Mn0.5 and Ni0.5Fe0.5 into B' and B″ sites. Controlling B-site cation systematically tailors the electronic structure of the B-site cation with a d-band center (Md) upshift close to the Fermi level, increasing the overlap of the Md center and O 2p center (OP). The strong interaction of Md and Op facilitates the adsorption of oxygen and activates the lattice oxygen to participate in the OER process, thereby enhancing the ORR and OER activity. For ORR, LSNMF exhibited an onset potential of 0.9V along with a high limiting current of -8.05mAcm-2. At the same time, for OER at 1m KOH, LSNMF effectively reached a maximum current density of 3000mAcm-2. Most importantly, the difference between EORR (at -1mAcm-2) and EOER (at 10mAcm-2), ΔE is 0.69V, which stands among the best of recently reported perovskites. The as-designed LSNMF is stable, efficient, lucrative, and a promising candidate for practical application.

Core-Shell Quantum Wires-Supported Single-Atom Fe Electrocatalysts for Efficient Overall Water Splitting.

It is of great significance for the development of hydrogen energy technology by exploring the new-type and high-efficiency electrocatalysts (such as single atom catalysts (SACs)) for water splitting. In this paper, by combining interface engineering and doping engineering, a unique single atom iron (Fe)-doped carbon-coated nickel sulfide (Ni3S2) quantum wires (Ni3S2@Fe-SACs) is prepared as a high-performance bi-functional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Theoretical calculation and experimental results show that the addition of atomic Fe species can effectively adjust the electronic structure of sulfide, the interfacial electron transfer modulates the d-band center position, optimizing the transient state of the catalytic process and adsorption energy of hydrogen/oxygen intermediates, and greatly accelerates the kinetics of HER and OER. The results show that the Ni3S2@Fe-SACs core-shell quantum wires array exhibit overpotentials of 46 and 219mV for HER and OER at 10mA cm-2 in 1m KOH, respectively. In addition, the two-electrode electrolyzer assembled by the Ni3S2@Fe-SACs requires a voltage as low as 1.465V to achieve alkaline overall water splitting of 10mA cm-2. This work holds great promise for the development of highly active and highly stable electrocatalysts for future hydrogen energy conversion applications.

Regulation of interfacial microenvironment by introducing Co atoms into MoSP compounds with enhanced catalytic activity for overall water splitting

Modulation of the interfacial microenvironment has proven to be an effective method to significantly improve the catalytic performance of electrocatalysts. Herein, a highly efficient electrocatalyst was successfully synthesized through the strategy of modulating the interfacial microenvironment by incorporating Co atoms into the MoSP composites (Co-MoSP). Particularly, the optimized Co-MoSP composites exhibited excellent electrocatalytic activities with the overpotentials of 282 and 71 mV for oxygen and hydrogen evolution reactions at 10 mA cm−2 and a small voltage of 1.51 V for overall water splitting at 10 mA cm−2 in 1 M KOH. Experimental data demonstrated that the incorporation of Co atoms into MoSP composites can greatly modulate the interfacial microenvironment and enhance the catalytic activity of the catalysts. This report showed that the use of the metal atom to regulate the interfacial microenvironment of the catalysts is a potential method to significantly boost the catalytic performance of the electrocatalysts.

Waste wood tar based porous carbon electrodes for supercapacitors with excellent performances through condensation cross-linking modification

Wood tar is an unavoidable by-product during a slow-pyrolysis process of biomass, which is usually discarded as a waste and results in environment pollution. Recently, wood tar has been used as a starting material for carbon electrodes because of its thermoplasticity and high carbon content. However, wood tar is mainly composed of various light phenolic molecules, which usually leads to a low carbonization yield after carbonization and an inferior electrochemical performance after activation. In this work, in order to improve the carbonization rate and electrochemical performance of these materials, wood tar was first condensed and crosslinked with formaldehyde and urea via a condensation reaction to produce condensed macromolecular resins, which were then carbonized at 550°C and activated with KOH at 800°C to prepare high-performance nitrogen-doped carbon electrodes for supercapacitors. The samples possess high carbonization yield, large specific surface area (3515.1 m2g-1) and moderate nitrogen content (1.11%). The high-performance carbon electrodes fabricated by this method achieves a high capacitance of 437.8Fg-1 (6M KOH electrolyte) at 1A/g-1. The assembled supercapacitor has an energy density of 13.41Whkg-1 at a power density of 124.93Wkg-1. And the capacitance retention was essentially 100% after 10000 cycles at 5Ag-1. The study presents an innovative strategy for the production of porous carbon for supercapacitors using wood tar and improves carbonization yield via condensation cross-linking modification.