Specific Area Research Articles

Ultra-Large Two-Dimensional Metal Nanowire Networks by Microfluidic Laminar Flow Synthesis for Formic Acid Electrooxidation.

Despite the great research interest in two-dimensional metal nanowire networks (2D MNWNs) due to their large specific surface area and abundance of unsaturated coordination atoms, their controllable synthesis still remains a significant challenge. Herein, a microfluidics laminar flow-based approach is developed, enabling the facile preparation of large-scale 2D structures with diverse alloy compositions, such as PtBi, AuBi, PdBi, PtPdBi, and PtAuCu alloys. Remarkably, these 2D MNWNs can reach sizes up to submillimeter scale (~220 μm), which is significantly larger than the evolution from the 1D or 3D counterparts that typically measure only tens of nanometers. The PdBi 2D MNWNs affords the highest specific activity for formic acid (2669.1 mA mg-1) among current unsupported catalysts, which is 103.5 times higher than Pt-black, respectively. Furthermore, in situ Fourier transform infrared (FTIR) experiments provide comprehensive evidence that PdBi 2D MNWNs catalysts can effectively prevent CO* poisoning, resulting in exceptional activity and stability for the oxidation of formic acid.

Ultra‐Large Two‐Dimensional Metal Nanowire Networks by Microfluidic Laminar Flow Synthesis for Formic Acid Electrooxidation

Despite the great research interest in two‐dimensional metal nanowire networks (2D MNWNs) due to their large specific surface area and abundance of unsaturated coordination atoms, their controllable synthesis still remains a significant challenge. Herein, a microfluidics laminar flow‐based approach is developed, enabling the facile preparation of large‐scale 2D structures with diverse alloy compositions, such as PtBi, AuBi, PdBi, PtPdBi, and PtAuCu alloys. Remarkably, these 2D MNWNs can reach sizes up to submillimeter scale (~220 μm), which is significantly larger than the evolution from the 1D or 3D counterparts that typically measure only tens of nanometers. The PdBi 2D MNWNs affords the highest specific activity for formic acid (2669.1 mA mg‐1) among current unsupported catalysts, which is 103.5 times higher than Pt‐black, respectively. Furthermore, in situ Fourier transform infrared (FTIR) experiments provide comprehensive evidence that PdBi 2D MNWNs catalysts can effectively prevent CO* poisoning, resulting in exceptional activity and stability for the oxidation of formic acid.

Efficient removal of cadmium from aqueous solution by chitosan grafted pillared bentonite

Developing an environmentally friendly adsorbent with high adsorption capacity and economic advantages is crucial for the treatment of cadmium (Cd)-contaminated wastewater. In this study, Bentonite (Bt), which is widely distributed in nature, was used to prepare a new type of chitosan (CS)-grafted polymerized aluminum-pillared bentonite (i.e., Al@Bt): CS@Al@Bt. This new material effectively addresses the issues of chitosan’s poor mechanical strength, limited load capacity, and the weak adsorption properties of raw bentonite for Cd. The effects of synthesis conditions on Cd adsorption by modified bentonite were investigated through batch experiments. The adsorption mechanism was revealed by characterization tests such as X-ray diffraction (XRD), N2 adsorption-desorption experiments, Scanning and Transmission electron microscopy (SEM-TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results showed that compared to raw Bt, when the ratio of Al in polymerized aluminum to the cation exchange capacity (CEC) of Bt was increased to 5 (i.e., Al/CEC=5), the specific surface area (SSA) of Bt increased from 78.46 m²/g to 195.99 m²/g. Additionally, the interlayer spacing and total pore volume increased by 1.22 and 1.13 times, respectively. After grafting chitosan onto Al@Bt, CS@Al@Bt reached adsorption equilibrium rapidly within 15 min, achieving a removal rate of up to 99.82% (initial concentration of Cd(II) was 20 mg/L, and the solid-liquid ratio was 1 g/L). Additionally, CS@Al@Bt showed good adsorption performance over a wide pH range. The rich pore structure of CS@Al@Bt and the complexation between amino (-NH2) and hydroxyl (-OH) groups with Cd(II) were the main mechanisms for the removal of Cd(II) from the solution. The application showed that CS@Al@Bt effectively reduced Cd-containing mining wastewater from class V to class II quality, underscoring its significant potential for treating Cd(II)-contaminated wastewater.

Electrospun Membranes Based on Quaternized Polysulfones: Rheological Properties–Electrospinning Mechanisms Relationship

Composite membranes based on a polymer mixture solution of quaternized polysulfone (PSFQ), cellulose acetate phthalate (CAP), and polyvinylidene fluoride (PVDF) for biomedical applications were successfully obtained through the electrospinning technique. To ensure the polysulfone membranes’ functionality in targeted applications, the selection of electrospinning conditions was essential. Moreover, understanding the geometric characteristics and morphology of fibrous membranes is crucial in designing them to meet the performance standards necessary for future biomedical applications. Thus, the viscosity of the solutions used in the electrospinning process was determined, and the morphology of the electrospun membranes was examined using scanning electron microscopy (SEM). Investigations on the surfaces of electrospun membranes based on water vapor sorption data have demonstrated that their surface properties dictate their biological ability more than their specific surfaces. Furthermore, in order to understand the different macromolecular rearrangements of membrane structures caused by physical interactions between the polymeric chains as well as by the orientation of functional groups during the electrospinning process, Fourier transform infrared (FTIR) spectroscopy was used. The applicability of composite membranes in the biomedical field was established by bacterial adhesion testing on the surface of electrospun membranes using Escherichia coli and Staphylococcus aureus microorganisms. The biological experiments conducted establish a foundation for future applications of these membranes and validate their effectiveness in specific fields.

Significantly enhanced photo response of hydrazine hydrate reduced graphene oxide films modified with swift heavy ion irradiation of silver (Ag8+) ions

In this paper, a multistep reduction process of graphene oxide (GO) is discussed. It is basically a two-step reduction process. In the first step, the GO sample is reduced by hydrazine hydrate. In the second step, it is further reduced by a swift heavy ion irradiation beam of silver (Ag8+) ions of 100 MeV energies. Ion beam irradiation causes defects in the hydrazine hydrate reduced graphene oxide (rGO) samples. FTIR study confirms the removal of oxygen containing functional groups. The pore volume and pore density of the samples seem to increase with increase in the ion irradiation doses. It is also seen that the electrical conductivity and specific surface area increases with dose of ion irradiation. The prepared samples were tested for photo response measurement and among all the sample, R5 had the highest photo response of 6.25 % at 30 mW/cm2. The photodetection response seems to increase with increase in intensity of light.

Activity in the Field of Blood Coagulation Processes of Poly(Lactide)-Zinc Fiber Composite Material Obtained by Magnetron Sputtering

This article presents the biochemical properties of poly(lactide)-zinc (PLA-Zn) composites obtained by DC magnetron sputtering of zinc onto melt-blown nonwoven fabrics. The biochemical properties were determined by the evaluation of the activated partial thromboplastin time (aPTT) and prothrombin time (PT). The antimicrobial activity of the PLA-Zn samples was additionally tested against representative Gram-positive and Gram-negative bacteria strains. A structural study of the PLA-Zn has been carried out using specific surface area and total pore volume (BET) analysis, as well as atomic absorption spectrometry with flame excitation (FAAS). PLA-Zn composites exhibited an antibacterial effect against the analyzed strains and produced inhibition zones against E. coli and S. aureus. Biochemical investigations revealed that the untreated PLA fibers caused the acceleration of the clotting of human blood plasma in the intrinsic pathway. However, the PLA-Zn composites demonstrated significantly different properties in this regard, the aPTT was prolonged while the PT was not altered.

Dual Stimulus Responsive GO-Modified Tb-MOF toward a Smart Coating for Corrosion Detection.

Smart-sensing coatings that exhibit multistimulus response, rapid indication, and reusability are in urgent need to effectively enhance the practicability of coatings while accurately detecting metal corrosion. In this work, a reusable corrosion self-reporting coating with multiple pH and Fe3+ stimulus responses was first constructed by the integration of a composite fluorescent probe into the resin matrix. This composite sensor was constructed by combining a lanthanide metal-organic framework (Ln-MOF) based on terbium and trimeric acid (H3BTC) with graphene oxide (GO) nanosheets (GO@Tb-BTC). The incorporation of GO formed a sea-urchin-like structure, thereby increasing the specific surface area and active sites of the probe. The coatings were characterized by using electrochemical impedance spectroscopy (EIS), visual observation, and fluorescence spectrophotometry. The surface morphology, wettability, and adhesion of the coating samples were analyzed using SEM, XPS, hydrostatic contact angle test, and an adhesion test. EIS measurements in 3.5 wt % NaCl solution for 72 h demonstrated the superior corrosion protection performance of the 0.3 wt %/GO@Tb-BTC/WEP coating compared to blank coating, with the charge-transfer resistance reaching 4.33 × 107 Ω·cm2, which was 9.5 times higher than that of the pure coating. The bright green fluorescence of GO@Tb-BTC/WEP coating exhibited a turn-off response when there was an excess of OH-/H+, but it demonstrated a reversible turn-on fluorescence when the ambient pH returned to neutral. Furthermore, such Fe3+-triggered fluorescence quenching responded to concentrations as low as 1 × 10-6 M. The fluorescence quenching rate of both intact and damaged coatings surpassed that of visual and EIS detection methods. Significantly, the fluorescence in scratches was effectively quenched within 25 min using 0.3 wt %/GO@Tb-BTC/WPU coating for visual observation. GO@Tb-BTC demonstrated exceptional corrosion self-reporting capabilities in both epoxy and polyurethane systems, making it a versatile option beyond single-coating applications.

Hydrogen peroxide electrosynthesis using commercial carbon blacks as catalysts: the influence of surface properties and adsorption performance

AbstractBACKGROUNDSurface properties and adsorption performance of carbon materials play a crucial role in the electrochemical two‐electron oxygen reduction to produce H2O2. However, there is still a lack of in‐depth research on commercial carbon blacks in this area. Herein, four typical commercial carbon blacks (Acetylene black (AB), Ketjen black EC 600JD, Vulcan XC 72 and Black Pearls 2000) were used as cathode catalysts to generate H2O2. Surface chemistry and pore structure of electrodes of the four carbon blacks were systematically characterized, and their effects on H2O2 adsorption, electrochemical generation and degradation were investigated.RESULTSAmong the four carbon blacks, AB has the highest content of C–O–C/COOH and CO, which are active groups catalyzing the two‐electron oxygen reduction reaction to generate H2O2. AB has the lowest level of defects and highest degree of graphitization, and AB‐modified graphite felt electrode (AB‐Ele) has the largest average pore diameter, smallest specific surface area and smaller charge transfer resistance. H2O2 production using AB‐Ele is the largest and reaches 567.7 mg L−1 at 180 min under a current density of 5 mA cm−2, and only decreases by 17.6% after 10 repeated uses.CONCLUSIONOverall, rich oxygen‐containing functional groups such as C–O–C, COOH and CO, high degree of graphitization, suitable surface area and porosity as well as weak H2O2 adsorption performance are beneficial for the two‐electron oxygen reduction reaction to generate H2O2. AB‐modified graphite felt electrode exhibits good catalytic activity and reusability in H2O2 electrosynthesis, demonstrating promising application prospects. © 2024 Society of Chemical Industry (SCI).

Effect of solid acid catalyst coupled decolorization process on the physicochemical properties and bioactive and volatile compounds of sesame oil

SummaryIn this study, the effects of citric acid‐loaded Hβ zeolite (F), activated clay and their modified decolorizers on the nutrients, volatile compounds and harmful substances of sesame oil in the decolorization process were evaluated. The results showed that the decolorization effect of F was second only to that of activated clay, the yield of F‐treated sesame oil sample was not significantly different from that of other decolorizers. The formation of asarinin was detected only in the sesame oil samples treated with F and H (zinc chloride‐activated clay). Compared with the activated clay‐treated sesame oil samples, the retention of tocopherols in the F‐treated sesame oil sample was significantly increased by 23.11%, and the retention of phytosterols was increased by 4.85%. The removal rate of the harmful substances Norharman and Harman in the F‐treated sesame oil sample was 96.79%, which was second only to that of the activated clay. Additionally, the removal rate of the total volatile compounds was the highest at 69.47%. The effects of different decolorizers on the sesame oil samples were closely related to the specific surface area, pore size and surface acidic sites of these decolorizers. This study could provide ideas for the industrial application of leached sesame oil, such as cosmetics and base oils.

Influence of Surface Basic Sites and Oxygen Vacancies on the Performance of Metal-Modified Rod-Like Ceria Catalysts for Low-Temperature Hydrolysis of Carbonyl Sulfide.

This study utilized a hydrothermal method to synthesize various metal-modified rod-like ceria catalysts (Fe, Co, Cu, Ni, La), achieving efficient COS removal at low temperatures. The research identified surface oxygen vacancies and basic sites as critical factors that influence the catalytic performance of COS hydrolysis. The addition of different metals to pristine ceria rods increased the specific surface area, oxygen vacancy content (Ov), and basicity, which enhanced the catalysts' sulfur resistance and stability. Among all the catalysts tested, 10La-CeO2 demonstrated the highest COS removal rate. This is because La doping significantly augmented Ov, providing more H2O adsorption and activation sites. Furthermore, 10La-CeO2 showed enhanced Lewis basicity, making it easier for COS to adsorb and promote hydrolysis. The in situ DRIFTS results confirmed that appropriate oxygen vacancies and basic sites favored the formation of intermediates such as HCO3 - and HSCO2 -, promoting the decomposition of COS into H2S and CO2.

Edge-Rich 3D Structuring of Metal Chalcogenide/Graphene with Vertical Nanosheets for Efficient Photocatalytic Hydrogen Production.

Constructing pertinent nanoarchitecture with abundant exposed active sites is a valid strategy for boosting photocatalytic hydrogen generation. However, the controllable approach of an ideal architecture comprising vertically standing transition metal chalcogenides (TMDs) nanosheets on a 3D graphene network remains challenging despite the potential for efficient photocatalytic hydrogen production. In this study, we fabricated edge-rich 3D structuring photocatalysts involving vertically grown TMDs nanosheets on a 3D porous graphene framework (referred to as 3D Gr). 2D TMDs (MoS2 and WS2)/3D Gr heterostructures were produced by location-specific photon-pen writing and metal-organic chemical vapor deposition for maximum edge site exposure enabling efficient photocatalytic reactivity. Vertically aligned 2D Mo(W)S2/3D Gr heterostructures exhibited distinctly boosted hydrogen production because of the 3D Gr caused by synergetic impacts associated with the large specific surface area and improved density of exposed active sites in vertically standing Mo(W)S2. The heterostructure involving graphene and TMDs corroborates an optimum charge transport pathway to rapidly separate the photogenerated electron-hole pairs, allowing more electrons to contribute to the photocatalytic hydrogen generation reaction. Consequently, the size-tailored heterostructure showed a superior hydrogen generation rate of 6.51 mmol g-1 h-1 for MoS2/3D graphene and 7.26 mmol g-1 h-1 for WS2/3D graphene, respectively, which were 3.59 and 3.76 times greater than that of MoS2 and WS2 samples. This study offers a promising path for the potential of 3D structuring of vertical TMDs/graphene heterostructure with edge-rich nanosheets for photocatalytic applications.

Preparation and Characterization of Lignin‐Based Activated Carbon by Rubidium Chloride Chemical Method

AbstractIn order to prepare carbon adsorbent materials, lignin was used as raw material and rubidium chloride as activator, activated carbon materials were prepared by chemical activation method, and its structure was characterized and its adsorption performance on methylene blue solution was investigated; the adsorption of crystalline violet dye was carried out at different temperatures, and the adsorption thermodynamics was studied. The results showed that: the specific surface area of the activated carbon was 433.32 m2/g, the pore volume was 0.2191 cm3/g, and the average pore size was 2.0222 nm; the adsorption value of methylene blue could reach 172.0 mg/g, and it could quickly and efficiently adsorb methylene blue solution; the adsorption effect on crystal violet solution was good, and the saturated adsorption amount at 40 °C was up to 279 mg/g, and the removal rate reached 93 %, belonging to the spontaneous adsorption thermodynamic reaction. The experiment proved that rubidium chloride can be used as an activator to activate lignin raw materials to prepare activated carbon samples, and can effectively adsorb dyes.

Enhanced Photocatalytic Activity of V2C MXene-Coupled ZnO Porous Nanosheets with Increased Surface Area and Effective Charge Transfer

Photocatalysis performs excellently when degrading organic pollutants, but the photocatalytic degradation rate is not high for most photocatalysts due to their narrow sunlight adsorption range and high recombination rate of electron hole pairs. Herein, we use V2C-MXene with a wide sunlight adsorption range to couple ZnO porous nanosheets and form ZnO/MXene hybrids using a facile electrostatic self-assembly method. The ZnO/MXene hybrids acquired demonstrated improved photochemical efficiency in breaking down methylene blue (MB) when contrasted with porous ZnO nanosheets. The degradation rate of MB reached 99.8% under UV irradiation for 120 min after the ZnO/MXene hybrid formation, while 38.6% was attained by the ZnO porous nanosheets. Moreover, photodegradation rate constants (k) were calculated as 3.05 × 10−3 and 5.42 × 10−2 min−1 for ZnO porous nanosheets and ZnO/MXene hybrids, respectively, indicating that the photodegradation performance was enhanced by 17.8 times after the modification of V2C. This was probably because the modification of V2C can increase the specific surface area to provide more sites for MB adsorption, widen the sunlight adsorption range to produce good photothermal effect, and facilitate the transfer of photogenerated carriers in ZnO to promote the reaction of more photogenerated carriers with MB. Hence, this work offers a simple approach to creating effective photocatalysts for breaking down organic contaminants.

Surface Modification of Polyimide Aerogel by Thermoplastic Polyurethane for Enhanced Mechanical Strength and Thermal Insulation Performance.

Polyimide (PI) aerogel is a good thermal insulation material with the highest temperature resistance in practical application. But the mechanical strength of PI aerogels prepared by freeze-drying or thermoimide methods is weak. In this research, TPU was selected as an aging solution to solve the problem of the low mechanical strength of PI aerogel prepared by the freeze-drying method. Previous work has certified that the coupling of PI and thermoplastic polyurethane (TPU) can enhance the mechanical strength of PI aerogel to a certain extent due to the flexibility of TPU. But excessive TPU will change the PI structure in the cross-linking process and decrease the mechanical strength of the aerogel. Thus, a new kind of PI gel modification method was provided by using TPU as an aging solution, and the mechanical strength of PI aerogel is improved to 3.06 MPa. Furthermore, the shrinkage, specific surface area, waterproof angle, and thermal conductivity all show good performance, thus enabling PI aerogel to be used in many aspects. Specially, the method is simple and can be used to prepare some other high-strength aerogels.

Rational design of nitrogen-doping Ti3C2Tx microspheres with enhanced polysulfide catalytic activity for lithium-sulfur batteries

The primary challenges that impede the practical applications of lithium-sulfur batteries are the significant shuttle effect of polysulfides, huge volume expansion, and slow redox kinetics. In this work, three-dimensional nitrogen doping Ti3C2Tx MXenes (3D N-Ti3C2Tx ) were successfully synthesized by spray drying and subsequent annealing, and hydrochloric acid-treated melamine effectively reduces the oxidation of MXenes in these processes. The formation of a unique nanoflower-shaped microsphere endows 3D N-Ti3C2Tx with a significant specific surface area and pore volume. The combination of nitrogen doping and the large specific surface area increased adsorption capacity and catalytic conversion ability for polysulfide intermediates. Consequently, the obtained 3D N-Ti3C2Tx /S cathode exhibited high-capacity retention (578.5 mAh g-1 after 500 cycles at 0.5 C and 462.5 mAh g-1 after 1,000 cycles at 1 C), superior rate performance (651.2 mAh g-1 at 3 C), and excellent long-term cycling performance (capacity fading rate of 0.076% per cycle at 0.5 C and 0.046% per cycle at 1 C). This work expands the potential applications of MXenes for lithium-sulfur batteries.

Stable and improved voltage plate of Li/SOCl2 battery using carbon electrodes with active carbon

Active carbon (AC) is synthesized using pitch coke as a precursor with a KOH activation approach followed. AC with different specific surface areas can be obtained by controlling the activation time of KOH. The activation time of AC1, AC2 and AC3 is 1 h, 1.5 h and 2 h, with the surface areas of 1233, 1484 and 1639 m2 g−1, respectively. The phase, surface chemical structure, morphology as well as the microstructure of the AC are investigated by XRD, Raman, IR, XPS, BET, SEM and TEM. The obtained ACs displayed a size around 300 μm with lots of nanoholes and functional group involving –OH, –COOH. When employed as the catalytic active materials in the carbon cathodes for Li/SOCl2 batteries, the discharged voltage was improved to around 0.15 V with an enhanced stable platform. Whereas the energy of the batteries containing the ACs is similar as that the conventional batteries, as well as the morphology of the carbon cathode with ACs exhibited a dense LiCl on the surface, suggesting that the ACs can enhance the reduction reaction of SOCl2, but could not act as the nucleation sites for the synthesis of nanoscale LiCl to form a loose film for a long discharge life.

Effect of Thermal Activation on the Structure and Electrochemical Properties of Carbon Material Obtained from Walnut Shells

A simple activation method has been used to obtain porous carbon material from walnut shells. The effect of the activation duration at 400 °C in an atmosphere with limited air access on the structural, morphological, and electrochemical properties of the porous carbon material obtained from walnut shells has been studied. Moreover, the structure and morphology of the original and activated carbon samples have been characterized by SAXS, low-temperature adsorption porosimetry, SEM, and Raman spectroscopy. Therefore, the results indicate that increasing the duration of activation at a constant temperature results in a reduction in the thickness values of interplanar spacing (d002) in a range of 0.38–0.36 nm and lateral dimensions of the graphite crystallite from 3.79 to 2.52 nm. It has been demonstrated that thermal activation allows for an approximate doubling of the specific SBET surface area of the original carbon material and contributes to the development of its mesoporous structure, with a relative mesopore content of approximately 75–78% and an average pore diameter of about 5 nm. The fractal dimension of the obtained carbon materials was calculated using the Frenkel–Halsey–Hill method; it shows that its values for thermally activated samples (2.52, 2.69) are significantly higher than for the original sample (2.17). Thus, the porous carbon materials obtained were used to fabricate electrodes for electrochemical capacitors. Electrochemical investigations of these cells in a 6 M KOH aqueous electrolyte were conducted by cyclic voltammetry, galvanostatic charge/discharge, and impedance spectroscopy. Consequently, it was established that the carbon material activated at 400 °C for 2 h exhibits a specific capacity of approximately 110–130 F/g at a discharge current density ranging from 4 to 100 mA/g.

An innovative label-free electrochemical aptamer sensor: utilizing Ti3C2Tx/MoS2/Au NPs for accurate interleukin-6 detection

In the medical field, changes in interleukin-6 (IL-6) concentration serve as essential biomarkers for monitoring and diagnosing various conditions, including acute inflammatory responses such as those seen in trauma and burns, and chronic illnesses like cancer. This paper detailed a label-free electrochemical aptamer sensor designed for IL-6 quantification. A composite material consisting of Ti3C2Tx and MoS2 was successfully synthesized to fabricate this sensor. The synergistic effect of MoS2's catalytic action on hydrogen peroxide (H2O2), used as a signalling marker, when combined with the exceptional conductivity and large specific surface area of Ti3C2Tx, not only enables an increased loading of MoS2 but also significantly boosts the electrochemical response. The in situ-reduced Au NPs provided stable immobilization sites for DNA aptamers (DNAapt) and facilitated electron transfer, ensuring accurate IL-6 recognition. Under optimal conditions, the aptamer sensor exhibited a wide linear range (5 pg/mL to 100 ng/mL) and a low limit of detection (LOD) of 2.9 pg/mL. Its sensing performance in human serum samples highlights its potential as a promising clinical analysis tool.

Enhanced reactivity over Ce2(SO4)3/MgO with NiO modification for chemical looping partial oxidation of methane

Chemical looping partial oxidation of methane to syngas is a promising process. Thermodynamic and kinetic analysis both forecast the NiO/Ce2(SO4)3–MgO is a prospective oxygen carrier (OC) to this process, which enables with 100% syngas selectivity, 2.15H2/CO ratio, excellent methane conversion and stable cycling characteristic. Compared with Ce2(SO4)3, the methane conversion rate rise by 73.19% because of the excellent lattice oxygen availability, less carbon deposit, and large specific surface area. The distinctive pore structure also provides a favorable reaction environment. Through the density functional theory, Ni doping can lower the energy barrier (Eb), promote lattice oxygen activation and diffusion, and the oxygen vacancy (Ov) can further promote these processes. CH3 → CH2 + H (TS2) is the rate-limiting step. Compared with Ce2(SO4)3, the Ni doping can reduce Eb by 16.8%, and the Ov can further reduce it by 43.0%. It does not change when the Ov concentration is more than 1.96%.

A novel layered cobalt oxide Ba2Co9O14 as an efficient and durable bifunctional oxygen electrocatalyst for rechargeable zinc-air batteries

In this work, a layered cobalt oxide Ba2Co9O14 (BCO), belongs to a Ban+1ConO3n+3(Co8O8) family composed by alternating CdI2 based layers (Co8O8) with n (111) perovskite blocks (Ban+1ConO3n+3), has been developed as a potential bifunctional oxygen electrocatalyst candidate for efficient and durable rechargeable zinc-air battery (ZAB) application. Because of the greatly increased the specific surface area caused by ball-milling, the as-milled BCO material exhibits strongly enhanced bifunctional electrocatalytic activity towards oxygen reduction and oxygen evolution reaction in alkaline medium. Moreover, the assembled BCO-based ZAB yields an effectively improved maximum output power density of 166 mW cm−2, a considerable specific capacity of 789 mAh g−1, and excellent charge-discharge cycle stability of over 250 h at 10 mA cm−2 with over 1500 cycles.