Copper Stabilizer Research Articles

Deactivation of Copper Electrocatalysts During CO2 Reduction Occurs via Dissolution and Selective Redeposition Mechanism

As electrochemical CO2 reduction (ECR) nears industrialisation levels, addressing the uncontrolled stability, restructuring, and deactivation of copper (Cu) catalysts during operation becomes as crucial as achieving high activity and selectivity...

Synthesis, Crystallographic Structure, Stability, and HSA-Binding Affinity of a Novel Copper(II) Complex with Pyridoxal-Semicarbazone Ligand

Copper–semicarbazone ligands have been extensively investigated for several medicinal applications. In this contribution, a novel copper(II) complex with a pyridoxal–semicarbazone ligand, [Cu(PLSC)Cl(H2O)](NO3)(H2O), was synthesized and characterized by X-ray crystallography, elemental analysis, UV-VIS, and FTIR spectroscopies. The stabilization interactions within the structure were assessed using the Hirshfeld surface analysis. The crystallographic structure was optimized at the B3LYP/6-311++G(d,p)(H,C,N,O)/LanL2DZ(Cu) level of theory. A comparison between the experimental and theoretical bond lengths and angles was undertaken to verify the applicability of the selected level of theory. The obtained high correlation coefficients and low mean absolute errors confirmed that the optimized structure is suitable for further investigating the interactions between donor atoms and copper, along with the interactions between species in a neutral complex, using the Quantum Theory of Atoms in Molecules approach. The electrostatic potential surface map was used to reveal distinct charge distributions. The experimental and calculated FTIR spectra were compared, and the most prominent bands were assigned. The interactions with human serum albumin (HSA) were assessed by spectrofluorometric titration. The spontaneity of the process was proven, and the thermodynamic parameters of binding were calculated. Molecular docking analysis identified the most probable binding site, providing additional insight into the nature of the interactions.

Bulk Layering Effects of Ag and Cu for Tandem CO2 Electrolysis.

The electrochemical reduction of carbon dioxide (CO2) presents an opportunity to close the carbon cycle and obtain sustainably sourced carbon compounds. In recent years, copper has received widespread attention as the only catalyst capable of meaningfully producing multi-carbon (C2+) species. Notably carbon monoxide (CO) can also be reduced to C2+ compounds on copper, motivating tandem systems that combine copper and CO-producing species, like silver, to enhance overall C2+ selectivities. In this work, we examine the impact of layered-combinations of bulk Cu and Ag by varying the location and proportion of the CO-producing Ag layer. We report an effective increase in the C2+ oxygenate selectivity from 23 % with a 100 nm Cu to 38 % for a 100 : 15 nm Cu : Ag layer. Notably, however, for all co-catalyst cases there is an overproduction of CO vs Cu alone, even for 5 nm Ag layers. Lastly, due to restructuring and interlayer mobility of the copper layer it is clear that the stability of copper limits the locational advantages of such tandem solutions.

Effects of Short-Term Annealing on the Thermal Stability and Microstructural Evolution of Oxygen-Free Copper Processed by High-Pressure Torsion.

This study explores the impact of short-term annealing on the thermal stability and mechanical properties of oxygen-free copper subjected to high-pressure torsion (HPT). Copper samples were deformed through HPT with varying numbers of turns at room temperature and subsequently subjected to short-term annealing at temperatures of 398 K and 423 K. Microstructural analysis revealed that annealing led to grain growth and a reduction in dislocation density, with samples processed with fewer HPT turns exhibiting more significant grain coarsening. The microhardness measurements indicated a reduction in hardness after annealing, particularly at the edges of the discs, suggesting recrystallization. Samples processed with 10 HPT turns demonstrated higher thermal stability and less grain growth compared to 1/2-turn samples. The findings suggest that post-HPT short-term annealing can be used to tailor the balance between strength and ductility in oxygen-free copper, enhancing its suitability for industrial applications.

Oxygen Evolution Reaction Activity and Stability of Copper and/or Manganese Cobalt Spinels

Gigawatt-scale hydrogen production using proton exchange membrane water electrolyzers may be limited by the availability of iridium (oxide), the current state-of-the-art catalyst for the oxygen evolution reaction (OER) in acid [1]. And yet, iridium-free catalysts have struggled to meet both the activity and stability of iridium oxide, much in part due to the thermodynamic instability of most transition metals in acidic OER conditions. Recently, though, reports of Cu, Co, and/or Mn containing iridium-free spinels have demonstrated promising performance [2–4].Notwithstanding, the degradation mechanisms of these spinel-type catalysts are not well understood, as well as design strategies to mitigate the degradation. To explore these topics, four iridium-free, spinel-type catalysts were synthesized, characterized, and assessed for activity and stability: CuCo2O4, MnCo2O4, Cu0.5Mn0.5Co2O4, and Co3O4. The synthetic route (sacrificial support method) was built upon a previous study on CuCo2O4 for the alkaline OER by our group [5]. X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy were performed to investigate the crystal structure (see Figure 1A), surface oxidation state, and morphology of the catalysts, respectively, both before and after accelerated stress tests (ASTs). Additionally, electrolyte samples were taken before and after ASTs to quantify catalyst dissolution.From Figure 1B, linear sweep voltammetry measurements revealed that the mixed metal oxides all demonstrated enhanced mass OER activity compared to the monometallic Co3O4. From chronoamperometry measurements at 1.8 V vs. RHE in 0.1 M HClO4 , the mixed metal oxide catalysts lasted over 20 hours before reaching approx. 10% of the initial activity. Stability testing in a membrane electrode assembly (750 mA cm–2 hold, Nafion 212) demonstrated over 500 hours of operation at approx. 2.6 V. Operando X-ray photoelectron spectroscopy (XPS) and near edge X-ray adsorption fine structure (NEXAFS) experiments, along with in-situ inductively coupled plasma mass spectrometry (ICP-MS) measurements, are planned to complement the pre- and post-AST ex-situ catalyst characterization. Although these materials have yet to reach the activity and stability of iridium oxide, they nonetheless provide insights on a promising family of iridium-free catalysts and their development. Acknowledgements This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. (DGE-1839285). Any opinion, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Figure 1

Selective hydroxylation of benzene via enhanced generation and utilization of hydroxyl radicals with CuZnSbO photocatalyst

Photocatalytic selective benzene hydroxylation via activation of C(sp2)–H under visible light remains a challenging reaction. Copper-incorporated mixed metal oxide photocatalysts have shown promise in addressing this difficulty by enabling visible light harvesting, controlled reactive oxygen species (ROS) generation, effective ROS utilization, and reactant adsorption. However, copper incorporated metal oxide catalysts were suffered from poor catalytic activity and selectivity due to leaching of Cu species. To solve this problem, herein, a novel stable mixed metal oxide (CuZnSbO) was prepared for the first time by applying a facile method. Copper introduction brought about the suitable band gap energy for a wide range of visible light harvesting of the CuZnSbO catalyst. The copper species play a key role in activating H2O2 to produce hydroxyl radicals (•OH) for benzene oxidation by controlling charge recombination. The mixed metal oxide of zinc and antimony supports the included copper strongly enabling copper stability. The CuZnSbO not only generates available hydroxyl radicals but also facilitates efficient hydroxyl radical consumption to initiate C(sp2)–H activation, forming benzene radical intermediates en route to phenol. That is ever reported. CuZnSbO delivered 31.51 % benzene conversion and 100 % phenol selectivity. This work demonstrates the promise of engineered mixed metal oxide that boosts Cu species utilization for H2O2 and benzene activation. The photocatalyst showed good activity in selective oxidative hydroxylation reactions through harnessing visible light and controlled ROS generation. Importantly, Cu cations govern the photocatalytic •OH generation mechanisms as shown by XPS and active site deactivation analysis.

Low-temperature photo imageable dielectric for redistribution layers in advanced packaging application

This study investigates the low-temperature photo imageable dielectric (LT-PID) as a next-generation material for redistribution layers (RDLs) in advanced packaging applications, with a focus on high-performance computing (HPC) and Artificial Intelligence (AI). LT-PID provides several critical advantages, including exceptionally low curing shrinkage, superior adhesion to key substrates such as silicon (Si), silicon oxide (SiOx), silicon nitride (SiNx), and copper (Cu), and robust thermal stability at lower processing temperatures. These properties make LT-PID an excellent candidate for enhancing the mechanical stability and reliability of fine-pitch interposers, a crucial requirement for heterogeneous integration in advanced packaging technologies. In addition, the optimization of lithography and plasma descum processes has shown that LT-PID contributes to improved contact resistance and uniform surface morphology. The use of O2/SF6 plasma descum significantly reduces via-bottom residue, further enhancing the electrical performance of Cu interconnects.

Copper Versatility in Hydroxyapatite: Valence States, Clusters, and Optical Absorption Properties.

The solid-state reaction between a stoichiometric hydroxyapatite (HA) and CuO at temperatures above 1100 °C produces pure Cux-HA phases for x ≤ 0.7 with the general formula Ca10CuIx(PO4)6(OH)2-xOx. The Cu atoms are located at the center of the hexagonal tunnels between two hydroxyl ligands, as determined by Fourier analysis based on XRD data. During heat treatment, the reduction of Cu2+ ions into Cu+ is concomitant with the stabilization of copper in HA in the hexagonal tunnel. The incorporation of monovalent copper within the apatite, as revealed by XANES spectroscopy, explains the violet color of the samples. The incorporation of Cu+ ions, by substitution of a hydrogen atom by copper(I), results in the formation of linear O-Cu-O chains where the majority of which are isolated for x ≤ 0.3. In addition, the EXAFS investigation showed, thanks to the linear geometry of these clusters that results in multiple diffusion effects, the existence of [CuO]n chains with n ≥ 2, which only appear clearly for higher copper contents x ≥ 0.5. The strong covalency of the Cu-O bond in such a dumbbell configuration would lead to strong hybridization between the 3d and 4s orbitals of copper and the 2p orbitals of oxygen, as illustrated by ESR signals. In the case of Cu-doped HA prepared by coprecipitation and annealed at a lower temperature (T ≤ 600 °C), copper substitutes calcium according to the theoretical formula Ca10-xCux(PO4)6(OH)2, mainly at the Ca(2) site. This local environment is in line with the Jahn-Teller distortion induced by the Cu2+ ion (as evidenced by UV-vis-NIR, XPS, and XANES-EXAFS spectroscopy analyses) and also allows copper-copper interactions from one site to another, as observed by ESR spectroscopy. This versatility of copper in HA gives it optical properties that change from a violet color with near-IR absorption to a blue hue. In all cases, Cu-O-Cu interactions persist whatever the valence state, and heat treatment induces a redox phenomenon, with copper exchanging between two sites close to each other.

Effect of CTAB and NaBH4 Solutions on Ti and Cu Nanoparticles Prepared by Pulsed Laser Ablation

The effect of different media, including cetyltrimethylammonium bromide (CTAB) and sodium borohydride (NaBH4), on the size, shape, optical absorption, and stability of titanium (Ti) and copper (Cu) nanoparticles (NPs) synthesized by laser ablation in liquid, was investigated. Ti and Cu NPs were fabricated by irradiating Ti and Cu targets using a Nd:YAG pulsed laser with a wavelength of 1064 nm, an energy of 500 mJ, repetition rate of 1 Hz, and a number of pulses of 1000. Results showed the direct effect of the type of surfactant on the size and size distribution of Ti and Cu NPs under the same laser ablation parameters. Morphological properties were described by field emission scanning electron microscope (FESEM) images, which revealed the formation of semispherical particles. The EDS results confirmed the spike-induced synthesis of Ti and Cu in CTAB and NaBH4 solutions. The transmission electron microscopy (TEM) images showed the nanostructures of Ti and Cu with spherical particles. The UV-vis absorption spectra showed that the absorption peak of Ti was almost constant at 289 nm, while the peak of Cu disappeared for both solutions. Zeta potential analysis showed that NPs prepared in CTAB solution were more stable than those in NaBH4 solution.

Effect of ionic liquid on dispersion stability and antiwear behavior of CuO nanoparticles added to polyalphaolefin base oil

The experimental study assessed the impact of choline chloride cation-based ionic liquid (IL), on the dispersion stability and wear characteristics of copper (II) oxide (CuO) nanoparticles (NPs) in synthetic base oil (PAO 10). CuO NPs, averaging 50 nm in size, underwent surface modification using varying concentrations of the IL (0.25%, 0.5%, 0.75%, and 1% by weight). The formulations were subjected to sliding wear tests to evaluate their wear behavior. Analysis of the worn surfaces utilized scanning electron microscopy, energy-dispersive x-ray spectroscopy, and atomic force microscopy. The results indicated that the combination of 0.75% IL and 1% CuO NPs provided optimal dispersion and exhibited effective surface mending, enhancing wear protection by 21.1% than that of PAO 10. The formulation containing 1% IL and 1% CuO NPs demonstrated the highest load carrying capacity among all tested compositions. In terms of wear behavior, the nanolubricant formulations with 0.75% and 1% IL outperformed the lubricant formulation containing 1 wt% of the commercial antiwear additive Zinc dialkyldithiophosphates (ZDDP).

Boosting Fenton-like catalytic performance and environmental stability of nano zero-valent copper (nCu(0)) catalyst by inhibiting the formation of oxide layer: Catalytic performance and mechanistic study

Nano zero-valent copper (nCu(0)) as Fenton-like catalyst has shown great potential in the treatment of organic wastewater. However, nCu(0) is prone to be agglomerated and oxidated, causing to the reduction in catalytic ability. Herein, biochar supported highly dispersed nCu(0) (Cu/C) was synthesized by the carbonization method. And acid-modified strategy was proposed to inhibit the oxidation of nCu(0). Physicochemical properties of Cu/C catalysts modified by different acid (HCl, H2SO4 and HNO3) were analyzed by various characterizations. The results showed that only the introduction of HCl could obviously inhibit the formation of oxide layer on Cu(0), while HNO3 and H2SO4 couldn’t. Furthermore, the content of oxide layers decreased with the increase in HCl addition. Correspondingly, the catalytic performance enhanced gradually. Cu(0) was proved to be the active centers. And the presence of oxide layers was adverse to the catalytic reaction. When the adding amount of HCl reached to 1 mL, the Cu/C-HCl-1.0 catalyst showed the optimal catalytic performance. 97.1 % of p-nitrophenol (PNP) was degraded within 60 min. The reaction rate was 7.6 times that of unmodified Cu/C catalyst. Furthermore, Cu/C-HCl-1.0 catalyst possessed excellent environmental stability. After being directly exposed to air for 4 months, catalytic performance had no obvious decrease. In addition, the catalyst showed efficient degradation ability to phenols, dyes and antibiotics. And it was not sensitive to the initial pH of the organic solution (3.7 ∼ 11.2). OH was confirmed to be the main reactive species for the degradation of organic pollutants, which was formed by the decomposition of PMS by obtaining electrons from Cu(0). This work proposed a novel and efficient method to enhance the catalytic ability and environmental stability of Cu(0) by inhibiting the formation of oxide layer.

Numerical modelling and measurement of the E-I characteristics of MgB2 wire in sub-cooled water ice

This work presents a comprehensive 3D numerical model of MgB2 multi-filamentary superconducting wires using the Finite Element Method (FEM) software, COMSOL Multiphysics® 6.0. The study aims to investigate the electro-thermal behavior of MgB2 composite wires during standard transport measurements at various initial temperatures under subcooled water ice conditions. By solving a series of partial differential equations governing heat transfer and dynamic current transport, the model provides detailed insights into the wire’s performance. The simulation results are rigorously compared with experimental E-I characteristics measured for 6-filament MgB2 wires with internal copper stabilization. This comparison validates the model and highlights its capability to predict the behavior of superconducting wires under cryogenic conditions. The findings offer valuable data on the current distribution, ohmic losses, and overall thermal stability of the composite wires, contributing to the advancement of cryogen-free superconducting technologies. This study bridges the gap in the literature regarding the electrothermal dynamics of MgB2 wires cooled by subcooled water ice, providing a foundation for further research and practical applications in high-field generation devices.

Optimized Fabrication of Flexible Paper‐Based PCBs with Pencil and Copper Electroplating

AbstractThis research unveils a transformative methodology for fabricating flexible printed circuit boards (PCBs), focusing on the unique attributes of filter paper substrates. A meticulous parametric exploration scrutinizes critical aspects such as buckling resistance, charging current, plating time, and electrode configurations for copper electroplating. Key findings highlight the exceptional stability of copper electroplating on filter paper, exhibiting robust resistance against environmental variations and bending angles spanning +180° to −180°. Utilizing higher pencil grade material and maintaining a minimum 4 cm distance with a voltage range of 3 to 1.44 V ensures uniform, controlled plating without burning, optimizing the electrode area below 1 cm2for enhanced practicality. The research underscores the longevity and durability of copper‐plated filter paper, with negligible resistance changes even after 1000 folds. Over a year, the shelf‐life assessment emphasizes the excellent stability of electroplated filter paper. Practical applications, including fully functional circuits and a bio‐degradable piano, underscore the versatility and real‐world feasibility of the proposed electroplating technique.

Synthesis, crystal structure, magnetic behaviour and thermal stability of a paddle-wheel copper(II) complex bearing equatorial 3,4-diethoxybenzoate ligands.

The binuclear paddle-wheel copper(II) complex tetrakis(μ-3,4-diethoxybenzoato-κ2O:O')bis[(ethanol-κO)copper(II)], [Cu2(C11H13O4)4(C2H6O)2], has been synthesized and characterized. In each molecule, two CuII centres are bridged in a syn-syn fashion by four equatorial 3,4-diethoxybenzoate ligands, the two axial positions being occupied by ethanol molecules. The thermal stability has been studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques. The magnetic behaviour, studied by SQUID magnetometry, shows a CuII-CuII antiferromagnetic exchange interaction with 2J= -288 cm-1, a value that fits with a magnetic structure correlation established for compounds of this kind.

Effect of Trace Elements on the Thermal Stability and Electrical Conductivity of Pure Copper

Abstract: The impact of introducing trace transition elements on the thermal stability and conductivity of pure copper was examined through metallographic microscopy (OM), transmission electron microscopy (TEM), and electrical conductivity measurements; the interaction between trace transition element and trace impurity element S in the matrix was analyzed. The results show that the addition of trace Ti and trace Cr, Ni, and Ag elements significantly enhances the thermal stability of the pure copper grain size. After high-temperature treatment at 900 °C/30 min, the grain sizes of Cu, Cu-Ti-S, and Cu-Cr-Ni-Ag-S were measured and found to be 200.24 μm, 83.83 μm, and 31.08 μm, respectively, thus establishing a thermal stability ranking of Cu-Cr-Ni-Ag-S > Cu-Ti-S > Cu. Furthermore, the conductivities of pure copper remain high even after the addition of trace transition elements, with recorded values for Cu, Cu-Ti-S, and Cu-Cr-Ni-Ag-S of 100.7% IACS, 100.2% IACS, and 98.5% IACS, respectively. The enhancement of thermal stability is primarily attributed to the pinning effect of the TiS and CrS phases, as well as the solid solution dragging of Ni and Ag elements. Trace Ti and Cr elements can react with S impurities to form a hexagonal-structure TiS phase and monoclinic-structure CrS phase, which are non-coherent with the matrix. Notably, the CrS phase is smaller than the TiS phase. In addition, the precipitation of these compounds also reduces the scattering of free electrons by solute atoms, thereby minimizing their impact on the alloy’s conductivity.

Modulation of Electronic Availability in g-C3N4 Using Nickel (II), Manganese (II), and Copper (II) to Enhance the Disinfection and Photocatalytic Properties.

Carbon nitrides can form coordination compounds or metallic oxides in the presence of transition metals, depending on the reaction conditions. By adjusting the pH to basic levels for mild synthesis with metals, composites like g-C3N4-M(OH)x (where M represents metals) were obtained for nickel (II) and manganese (II), while copper (II) yielded coordination compounds such as Cu-g-C3N4. These materials underwent spectroscopic and electrochemical characterization, revealing their photocatalytic potential to generate superoxide anion radicals-a feature consistent across all metals. Notably, the copper coordination compound also produced significant hydroxyl radicals. Leveraging this catalytic advantage, with band gap energy in the visible region, all compounds were activated to disinfect E. coli bacteria, achieving total disinfection with Cu-g-C3N4. The textural properties influence the catalytic performance, with copper's stabilization as a coordination compound enabling more efficient activity compared to the other metals. Additionally, the determination of radicals generated under light in the presence of dicloxacillin supported the proposed mechanism and highlighted the potential for degrading organic molecules with this new material, alongside its disinfectant properties.

Al-doped oxide-derived copper catalyst with stable Cu+ site for efficient electrocatalytic CO2 reduction to C2H4

Electrocatalytic carbon dioxide reduction reaction (ECO2RR), a pivotal process converting CO2 into high-value products, plays a crucial role in advancing objectives of carbon neutrality. Within various catalysts, copper-based electrocatalysts hold a unique position as they demonstrate a remarkable aptitude for producing high-carbon (C2+) products. Notably, the well-established Cu+ sites exhibit robust C-C coupling capabilities, particularly in the synthesis of C2H4 products. However, the challenge lies in maintaining the stability of oxide-derived copper under the negative potential operating conditions. In light of this, we use the ion exchange principle to make Al partially replace Cu-BDC, and then get a dopant by high temperature calcination to prepare Al-doped CuO catalyst. It has been demonstrated that the introduction of oxyphilic Al atoms could induce the redistribution of electrons in the CuO matrix and stabilize the presence of Cu+ in the ECO2RR process. This configuration significantly enhances the catalytic performance of CuO for electrochemically converting CO2 into C2H4. Specifically, the optimized Al-CuO catalyst exhibits ∼50 % Faradaic Efficiency for C2H4 (FEC2H4) at −1.377 V vs. RHE, doubling the performance compared to pure CuO. The design and implementation of doping engineering presented in this work propel advancements in the field of electrocatalytic CO2 reduction for C2H4 production, offering a crucial avenue for the development of efficient catalysts.

Unusual Stability of an End-on Superoxido Copper(II) Complex under Ambient Conditions.

Superoxido copper complexes play an important role as usually short-lived intermediates in biology and chemistry. The unusual stability of an end-on superoxido copper complex observed in an oxygen-enhanced atom transfer radical polymerization (ATRP) led to a detailed mechanistic investigation of the formation of [CuII(Me6tren)(O2⋅-)]+ (Me6tren=tris(2-dimethyl-aminoethyl)amine) under ambient conditions. The persistence of the superoxido copper complex could be explained by a reaction cycle including the peroxido complex [(Me6tren)2CuII 2(O2)]2+ together with [CuI(Me6tren)(DMSO)]+ and [CuII(Me6tren)(OH)]+ in the overall reaction.

The Stabilization of Copper and Cadmium in The Hydrated CaO-CuO-SiO2 and CaO-CdO-SiO2 Composites

The stabilization of toxic metals in the stable matrices is quite well-known. Research on copper and cadmium stabilization in the CaO-CuO-SiO2 and CaO-CdO-SiO2 composites was conducted to study the characteristics of CaO-CuO-SiO2 and CaO-CdO-SiO2 composites as well as the Cu and Cd metals stabilization in the hydrated composites. The composites of CaO-CuO-SiO2 and CaO-CdO-SiO2 were synthesized by the solid-state reaction method. A stoichiometric amount of CaO, SiO2, Cu(NO3)2, and CdO were calcined at 1050°C for 4 hours. The synthesized compounds were further hydrated in a soaking time of 30, 60, and 90 days. The hydration produced calcium silicate hydrate that can stabilize metals. The Cu and Cd stability in CaO-CuO-SiO2 and CaO-CdO-SiO2, respectively, were tested using the Toxicity Leaching Procedure (TCLP) method. The hydrated and hydrated composite characterizations were performed using X-ray diffraction (XRD), Fourier Transform Infra-Red Spectrophotometer (FTIR), and Scanning Energy Mocroscopy-Energy Dispersive X-ray analyzer (SEM-EDX) and the Atomic Absorption Spectroscopy (AAS) methods. The composites mainly consist of Ca3SiO5, Ca2SiO4, Ca(OH)2, SiO2, and metal oxide of CuO, Cu2O, and CdO. The composites were able to stabilize ~100% of the heavy metals of Cu and Cd.

Temporal changes in the mobility of As, Pb, Zn, and Cu due to differences in biochar stability caused by lignin content

Understanding biochar aging is a critical factor in predicting its long-term effects when added to soil. This study explores the complex links between lignin content in biochar feedstock and biochar stability during accelerated aging, including its influence on heavy metal mobility in soil. In this study, nine types of biochar based on fir (F), pine (P), and oak (O) sawdust were produced at 400 °C, and lignin was extracted from them using ammonia after 0, 3, and 7 days (named as 0FB, 3FB, 7FB, 0PB, 3PB, 7PB, 0OB, 3OB, and 7OB). Subsequently, each biochar was subjected to 25 cycles of wet-dry (WD) and freeze–thaw (FT) aging. The aged low-lignin biochars (7FB, 7 PB, and 7OB) released more dissolved organic matter (DOM) and contained more oxygen-containing surface groups on their surfaces than the high-lignin biochars (0FB, 0PB, and 0OB). The low-lignin biochars with high DOM leaching released 37–85 % more anionic arsenic (As) from biochar-amended soil after 25 cycles of aging than the high-lignin biochars. The stabilities of lead (Pb), zinc (Zn), and copper (Cu) were increased due to strong binding to surface functional groups on the low-lignin biochar. The acid-soluble fractions of Pb, Zn, and Cu were converted to organic-bound fractions as biochar aging progressed, with the degree of transformation being inversely proportional to the lignin content of biochar. This research highlights the crucial role of lignin in shaping biochar stability, and reveals how biochar stability impacts soil heavy metals speciation, opening new avenues for effective biochar-based environmental solutions and the promotion of soil health.