Carbon Cloth Research Articles

Multiphase lattice engineering of bimetallic phosphide-embedded tungsten-based phosphide/oxide nanorods on carbon cloth: A synergistic and stable electrocatalyst for overall water splitting

The hierarchical design of the three-dimensional (3D) nanoarchitecture, comprising multiple phases within an interconnected network on a conductive substrate, offers a high specific surface area, abundant exposed active sites, and rapid electron transport. In our study, we synthesized a hybrid catalyst by integrating (Fe,CO)-P nanoparticles into uniformly grown W-(O,P) nanorods on carbon cloth (CC) using a straightforward method, demonstrating notable electrocatalytic performance. The as-synthesized (Fe,CO)-P/W-(O,P)@CC exhibited remarkable performance in both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) for overall water splitting. It achieves overpotentials of 210 and 61.3 mV for the OER and HER, respectively, at a current density of 10 mA cm−2 in a 1 M KOH solution. As a bifunctional electrocatalyst in overall water splitting, (Fe,CO)-P/W-(O,P)@CC needs only 1.50 V to attain a current density of 10 mA cm−2, surpassing traditional Pt/C@CC and IrO2@CC counterparts (1.53 V @ 10 mA cm−2). The synergistic effects between (Fe,Co)-P and the W-(O,P)@CC nanohybrid heterostructure enhance the charge transfer, further promoting the activity of this hybrid electrocatalyst. This study reveals a promising avenue for advanced water electrolysis applications.

Superior cycle stability and enhanced pseudocapacitive performance of NiAl-LDH decorated carbon cloth for supercapacitor application

Pseudocapacitors, particularly using layered double hydroxides as cathode material, offers high-power capability and increased energy density, making them popular choices for energy storage devices. This study presents a unique porous structure featuring nickel aluminium layered double hydroxide (NiAl-LDH) deposited onto activated carbon cloth (CC) via a single-step electrochemical process. The NiAl-LDH@CC composite demonstrates exceptional pseudocapacitive capabilities with a specific capacitance of 5893.8 mF cm−2 at a current density of 0.7 mA cm−2 calculated from galvanostatic charge–discharge (GCD) responses. An asymmetric supercapacitor (ASC) is constructed using activated carbon cloth (CC) as anode and NiAl-LDH@CC as cathode. The as-built ASC device, with an operational voltage of 1.6 V, achieves a substantial specific capacitance of 310 mF cm−2 at a current density of 0.2 mA cm−2, along with a high energy density ∼51.67 μWh cm−2 and a power density ∼913.84 μW cm−2. An outstanding cycle stability is also observed with a retention rate of 90 % after 10000 continuous GCD cycles.

Oxygen atom activated ZIF-67/carbon cloth in plasma system for CO2 reduction

ZIF-67 was grown in situ on carbon cloth (CC) using a simple one-step method. The prepared ZIF-67/CC electrodes exhibited excellent CO2 reduction reaction (CO2RR) performance in a dielectric barrier discharge plasma reactor. The highest concentrations of produced formic acid and formaldehyde were 9.16 and 0.068 mmol L−1 at a reaction time of 1 h, respectively. The high performance is related to the unique high aspect ratio structure and pad-like cavity of ZIF-67, which results not only in an increase in the specific surface area for CO2 adsorption but also in the hydrophobicity of the electrode. Unexpectedly, the superoxide radical (·O2−) greatly affects the reduction performance of the electrode. In addition, the ZIF-67/CC electrode maintained good CO2RR performance in the presence of different pollutants, and the production of formic acid and formaldehyde increased to 10.81 and 0.11 mmol L−1 at 1 h with the addition of 10 mg L−1 phenol. This research provides new directions in the field of plasma catalysis.

Unveiling electron transfer and radical transformation pathways in coupled electrocatalysis and persulfate oxidation reactions for complex pollutant removal

The degradation of multiple organic pollutants in wastewater via advanced oxidation processes might involve different radicals, of which the types and concentrations vary upon interacting with different pollutants. In this study, electrochemical activation of peroxymonosulfate (E/PMS) using advanced activated carbon cloth (ACC) as electrode was applied for simultaneous degradation of mixed pollutants, e.g., metronidazole (MNZ) and p-chloroaniline (PCA). 92.5 % of MNZ and 91.4 % of PCA can be degraded at the cathode and anode at a low current density and PMS concentration, respectively. The rate constants for the simultaneous removal of MNZ and PCA in the E/PMS/MNZ(PCA) system were 118 times and 6 times higher than those in the sole PMS system, and 2.5 times and 1.6 times higher than those in the E/Na2SO4/MNZ(PCA) system, respectively. Different electrochemical characteristics, EPR spectra and radical quenching tests verified that the degradation of MNZ and PCA in the optimal system proceeded primarily through non-radical-dominated oxidation, involving electron transfer and 1O2 effect. The system also exhibited low energy consumption (0.215 kWh/m−3·order−1), broad operational pH range, excellent removal efficiency for water matrix, and low by-products toxicity, indicating its strong potential for practical applications. The ACC, with its super stable, low cost, and electrochemical activity, make it as a promising materials applicable in the E/PMS system for degradation of multiple pollutants. The study further elucidated the mechanism of pollutant interaction with electrode materials in terms of radical and non-radical transformation, providing fundamental insight into the application of this system for treatment of complex wastewater.

Electrophoresis study on carbon cloth loaded with LiFePO4 for integrated flexible cathodes in lithium-ion batteries

Electrophoresis study on carbon cloth loaded with LiFePO4 for integrated flexible cathodes in lithium-ion batteries

Flexible Ag2Se/Ag2S nanocomposite on carbon fabric optimized via interfaced engineered energy filtering effect for a textile based wearable thermoelectric generator

Wearable devices have become increasingly attractive in wearable electronics due to their advantages of environmental friendliness and foldability. The state-of-the-art thermoelectric system depends on inorganic semiconductors that show high electron mobility but lack mechanical stability and thermoelectric performance. Here, We have proposed a solvothermal method to grow Ag2Se/Ag2S nanocomposite on carbon fabric with outstanding properties, demonstrating excellent flexibility. The crystallographic analysis was performed for all samples through XRD and confirmed the orthorhombic Ag2Se and mono-clinic Ag2S. Further, the morphological analysis revealed the enhanced growth on the carbon fabric. We investigated the thermoelectric properties of Ag2Se/Ag2S nanocomposite and achieved a high power factor of 8.1 μW/mK2 which is twice as high as the percentage of the pure Ag2Se. Additionally, thermoelectric legs were fabricated using Ag2Se/Ag2S nanocomposite in a 2-pair module. They produced an output voltage of 0.1 mV to 7.4 mV at a temperature gradient (ΔT) of 3–8 K. This work is a promising approach for obtaining high-performance wearable thermoelectric device.

Plasmonic Au-NPs photodecorated on NiCoLDH nanosheets as a flexible SERS sensor for the real-time detection of fipronil

Rapid extraction and detection of probe molecules from curved surfaces is critical for on-site and real-time detection. In this study, a flexible platform was developed using carbon cloth (CC) to create honeycomb-like nickel cobalt layered double hydroxides (NiCoLDH) nanosheets via a simple electrodeposition technique, which were then decorated with gold nanoparticles (Au-NPs) via photodeposition process. The Au-NPs/NiCoLDH/CC was designed as a surface-enhanced Raman scattering (SERS) substrate for detecting the broad-spectrum insecticide, Fipronil (FP). The fabricated sensor achieves a superior SERS activity due to the electrodeposited NiCoLDH, which provides the charge-transfer effect, and the photodeposited Au-NPs, which generate efficient SERS hotspots through the electromagnetic effect. The Density Functional Theory (DFT) calculation was used to estimate the optimal geometry and frontier molecular orbital diagrams of the FP molecules. The influence of electrodeposition time on NiCoLDH production and Au-NPs decorating quantity was investigated in detail. Furthermore, the flexible SERS sensor has excellent sensitivity, homogeneity, a low limit of detection (LOD), and high reproducibility for FP detection. Even after 40 cycles of bending and torsion, the SERS substrate maintained excellent mechanical endurance. Through a direct-sampling approach, FP molecules on the surfaces and mesocarp region of grapes and tomatoes were successfully detected with lower LOD. These findings highlight the outstanding potential of the produced flexible SERS sensor for real-time and on-site insecticide detection, making it valuable for food security analysis and monitoring.

Deliberate Amorphization of Co-MOF for Constructing Crystalline-Amorphous Heterostructures Toward High-Performance Water Electrolysis.

The endowment of metal organic frameworks (MOF) with superior electrocatalytic performance without compromising their structural/compositional superiorities is of great significance for the development of renewable energy devices, yet remains a grand challenge. Herein, a deliberate partial amorphization strategy is developed to construct a heterostructured electrocatalyst consisting of crystalline Co-MOF and amorphous Co-S nanoflake arrays aligned on the carbon cloth (CC) substrate (abbreviated as Co-MOF/Co-S@CC hereafter) through a rapid sulfuration method. The simultaneous implement of crystalline-amorphous (c-a) heterostructure and nanoflake arrayed architecture on CC substrate renders the Co-MOF/Co-S@CC with abundant and tight active sites, accelerated charge transfer rate, regulated electronic structures, and reinforced structural stability. As such, the obtained Co-MOF/Co-S@CC electrode demonstrates outstanding electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances with the overpotentials of 64 and 217mV at 10mA cm-2, respectively. Moreover, a two-electrode electrolyzer assembled by Co-MOF/Co-S@CC electrodes exhibits the lower cell voltages and larger current densities than those of Pt/C and RuO2 counterparts, excellent reversibility and prominent long-term stability, representing a great prospect for feasible H2 production. This adopted concept of c-a heterostructure for electronic regulation may bring about insightful inspiration for designing high-performance electrocatalysts for sustainable energy systems.

Synergistic interface engineering of ZnCo2O4/NiMnCo-layered double hydroxides for boosted reactivity in advanced supercapacitor electrodes

NiMn layered double hydroxide (LDH) exhibits high redox activity as a cathode material for hybrid supercapacitors, but it has the disadvantages of low conductivity and poor stability. In this work, the electrochemical properties of NiMnCo-LDH with different Co contents prepared by electrodeposition were tested. The results showed that the addition of an appropriate amount Co increased the adsorption of OH− on NiMn-LDH and improved the reactivity of the material. ZnCo-MOF grown on carbon cloth was transformed into flake ZnCo2O4 by calcination, and NiMnCo-LDH was electrodeposited on it to prepare ZnCo2O4/NiMnCo-LDH composite electrode. The core-shell structure increases the reaction area between the LDH material and the electrolyte. Physical characterization and density functional theory (DFT) calculations show that the structure and electronic distribution of ZnCo2O4/NiMnCo-LDH at the heterogeneous interface are reconstructed, which increases the valence state of Co and Mn elements, and finally exhibits enhanced electrochemical performance. Due to the existence of this synergistic effect, the specific capacity of the electrode is as high as 231.5 mAh g−1, with excellent stability demonstrated after 5000 cycles compared to the NiMnCo-LDH. The assembled hybrid supercapacitor exhibits a high energy density of 39.4 Wh kg−1, and has high cycle stability (90 % after 5000 cycles).

Fabrication of abundant oxygen vacancies in MOF-derived (Fe,Co)3O4 for oxygen evolution reaction and as an air cathode for zinc-air batteries

Metal-organic frameworks (MOFs) find wide-ranging applications owing to their adjustable structures, diverse compositions, and large specific surface area. In this work, MOFs materials were grown in situ on carbon cloth, yielding self-supported electrodes VO-(Fe,Co)3O4@CC rich in oxygen vacancies through a simple high-temperature annealing treatment utilizing NaBH4 as an etchant. Thus the resulting self-supported electrode VO-(Fe,Co)3O4@CC exhibited excellent oxygen evolution reaction (OER) performance, achieving an overpotential of merely 288 mV at 10 mA cm−2, along with a low Tafel slope of 31.39 mV dec-1, and demonstrating robust long-term activity and stability. In addition, a liquid zinc-air battery was assembled utilizing the prepared VO-(Fe,Co)3O4@CC as an air cathode, achieving a high open-circuit voltage of 1.46 V and a high peak power density of 89.06 mW cm−2, and it maintained excellent cycling stability during cyclic charging and discharging (with a current density of 2 mA cm−2) over a 32 h period. Meanwhile, the self-supported electrode VO-(Fe,Co)3O4@CC served as an air cathode for assembling an all-solid-state flexible zinc-air battery (ZAB), demonstrating a high peak power density (38.21 mW cm−2) and exhibiting favorable cycling stability. This experiment offers insights into the potential application of MOF-derived electrocatalysts in water decomposition and zinc-air batteries.

Synergistic effects of various membrane and cathode electrode types in dual chamber microbial fuel cells for wastewater treatment: Investigation of the start-up phase, modeling using artificial neural networks, and cost analysis

Although various membrane and cathode electrode types have been investigated in dual chamber microbial fuel cells (DCMDCs), there is no agreement on which combination of electrodes and separator materials works best. The main objective of this study is to investigate the synergistic effects of cathode electrodes and membranes on the performance of DCMFCs during the start-up phase, to model the DCMFCs through artificial neural networks (ANN), and to determine the most cost-effective choice. Principal component analysis was used to analyze the interrelationships among various factors that influence DCMFCs. Two types of ion exchange membranes (cation exchange membrane and anion exchange membrane) and two types of cathode electrodes (carbon cloth covered with 20% Pt as catalyst and plain carbon cloth) were studied. Electrodes and membranes were analyzed using AFM, TEM, SEM, XRF, and FTIR to investigate changes in morphology and the potential of fouling. The results showed that DCMFC with cation exchange membrane (CEM) and plain carbon cloth (CC) generated the maximum power among the investigated configurations. The average voltage values and COD removal efficiency reached 748 ± 13 mV and 57.8 ± 2.5%, respectively. The maximum power density achieved was obtained when the external resistance was set at 1000 Ω and was 180 mA/m2. ANN was successful in predicting the output voltage for the examined DCMFCs. The use of DCMFC with CC and CEM can be considered optimal in terms of performance and cost.

A mild, configurable, flexible CoNi-LDH(v)/Zn battery based on H-vacancy-induced reversible Zn2+ intercalation

Flexible Zn-based batteries have attracted increasing research interest as essential components of wearable energy storage devices. However, the advancement of flexible aqueous Zn-based batteries based on Co-Ni layered double hydroxide (CoNi-LDH) as the cathode material is hampered by their poor cycling stability and the corrosiveness of alkaline electrolytes. Herein, CoNi-LDH nanosheets enriched with H vacancies (CoNi-LDH(v)) were constructed on a flexible carbon cloth (CC) substrate via electrochemical deposition and activation. The Zn-based battery comprising CoNi-LDH(v)@CC as the cathode exhibited highly reversible conversion reactions and stable operation in 3 M ZnSO4 electrolyte (pH = 4). The battery delivered an excellent specific capacity (225 mA h g−1, 0.26 mA h cm−2), acceptable cycling stability (53.9%, 900 cycles), and high discharging voltage. The abundant H vacancies served as active sites for the reversible intercalation of Zn2+ and the extravasation of NO3− generated channels and space for Zn2+ transport and storage, together enabling an excellent Zn2+ storage capacity. Furthermore, a sandwich-structured solid-state CoNi-LDH(v)@CC//Zn@CC battery was fabricated and was found to exhibit a noteworthy electrochemical performance and mechanical durability. As a proof of concept, the unencapsulated battery powered a digital watch under various deformation conditions and operated stably for 80 h. Additionally, the flexible battery displayed outstanding customizability, maintaining an open-circuit voltage of 1.42 V even after being cut twice. The proposed engineering strategy contributes to the realization of textiles with truly wearable energy-storage devices.

An ultrafast, stable and highly reversible nickel magnesium vanadate cathode for magnesium ion batteries

Rechargeable magnesium batteries are one among the strongest candidates over lithium ion batteries with abundance, cost effective and less environmental hazard. However, limitations including slow Mg2+ ion kinetics in the electrode-electrolyte interface and formation of passivating layers on the surface of magnesium metal anode affecting the rechargeable behavior of a cathode. Herein, hydrothermally synthesized NiMg2(VO4)2 nanomaterial used as cathode. The oxidation and reduction properties of Mg and V facilitates the diffusion pathway for Mg2+ and Li+ ions. Additionally, the employment of activated carbon cloth as anode diminishes the strong ionic interactions between Mg2+ ions and crystal lattice, enabling the faster diffusion of Mg2+ ions. All the electrochemical investigations are carried out at room temperature in the potential window of 1.23 V to 3.83 V against Mg/Mg2+. At a lower current density of 100 mA g−1, the specific discharge capacity have been 220 mAh g−1 for the 2nd cycle and retention of 97.1 % over 25 cycles. The specific capacity increases with more Mg2+ involvement in the reaction. At the highest current rate of 5000 mA g−1 the capacity retention is 96.8 % after 1000 cycles. Calculated energy density for a low current density is 556 Wh kg−1. The presence of multivalent V ions in the cathode reduces volume expansion, assisting charge redistribution to maintain electroneutrality. The dynamic valence property of. Vanadium ions (V2+/V5+) assist the intercalation of Mg2+ ions into the crystal lattice of cathode and possibly contribute to the highly stable and reversible discharge capacity over cycles. These findings provide a new perspective on NiMg2(VO4)2 as cathode material for magnesium ion batteries.

Nickel aluminum selenide wrapped by NiCoAl-layered double hydroxide enables a robust structure for supercapacitors

To explore a simple and convenient strategy for the construction of hybrid composites as advanced electrode materials for supercapacitors (SCs), this research realized the construction of nickel − aluminium selenide (NiAlSe)@NiCoAl-layered double hydroxide (NiCoAl-LDH) heterostructure. In-situ hybridization of NiCoAl-LDH nanosheets onto NiAlSe nanoparticles anchored on carbon cloth generates a special core–shell heterostructure, which enhances the exposure of active centers and increases the surface area. The formation of heterogeneous interfaces between NiAlSe and NiCoAl-LDH alters the electronic architecture and accelerates the electron/ion migration. By making full use of the structural benefits and the cooperative effect, the NiAlSe@NiCoAl-LDH composite electrode delivered a large capacitance (Cs) of 1789.2F/g at 1 A/g along with a high retention rate of 94.7 % over 5,000 cycles, which outperforms the bare NiAlSe and NiCoAl-LDH. Meanwhile, the assembled NiAlSe@NiCoAl-LDH hybrid supercapacitor (HSC) attained maximum specific energy (Es) of 71.5 Wh kg−1. This HSC device exhibits superior cyclic durability of 92.1 % after 30,000 cycles. Thereby, this research offers valuable insights into the construction of robust electrode materials for advanced HSC devices.

Achieving highly interfacial evaporation rate and continuous salt resistance simultaneously via multi-dimensional composite biomimetic evaporator

In response to the global freshwater crisis, various measures have been proposed. Solar-driven interfacial photoevaporation is gaining attention because its environmentally friendly and energy-efficient. However, challenges such as low solar-thermal conversion efficiency and low evaporation rates continue to hinder the advancement of solar photoevaporation technology. Inspired by Tamarisk, we proposed a multistage reflective structure using a hydrothermal method, increasing the carbon cloth (CC) surface area. Numerical simulations indicate that the plasmon resonance effect of the composites could effectively enhance the light absorption properties of the structures. Subsequently, a polyvinyl alcohol-phytic acid (PVA-PA) hydrogel was integrated with the composites to achieve effective separation of the evaporation layer from the water transport layer, thereby minimizing the interfacial light evaporation material. The PVA-PA/MnO2@CC evaporation system demonstrates excellent thermal management performance. Both experimental and simulation results confirm that the system can localize the heat obtained from photothermal conversion at the water–air interface. Additionally, the Marangoni effect, induced by the temperature gradient in the evaporation system, facilitates the transport of water in the PVA-PA hydrogel to the interface through microscopic holes. The evaporator exhibited an evaporation rate of 3.190 kg m-2h−1 in deionized water, with an evaporation efficiency of 94.1 %. Even under high-concentration brine conditions, the evaporation rate remained high, and during continuous evaporation in high-concentration brine, the surface showed no significant salt accumulation. In summary, this work combines two-dimensional carbon cloth with three-dimensional hydrogel, and incorporates metal oxides onto the carbon cloth surface to further enhance its light-trapping ability. By synthesizing the advantages of both materials, the performance of the evaporator is significantly improved.

Low-tech innovation: biomimetic solid-contact potentiometric sensor for nanomolar-level atrazine detection.

Despite the fact that there are already a number of solid-contact-based ion-selective electrodes designed for atrazine detection, our ground-breaking contribution lies in introducing the first-ever atrazine potentioselectrode, enabling the ultra-sensitive detection of atrazine at nanomolar levels. Solid-contact ion-selective electrodes can offer advantages, such as improved stability, reproducibility, sensitivity, and selectivity compared to their liquid-contact counterparts. Here, a biomimetic potentiometric sensor for Atrazine was developed using economic, light weight, and flexible carbon cloth as solid-contact material. Our methodology entails the synthesis of a molecularly imprinted polymer (MIP) through straightforward precipitation polymerization, showcasing a streamlined and efficient method for creating highly specific molecular recognition elements. The validation of template removal is confirmed via meticulous analysis employing EDX and FTIR techniques, ensuring the efficacy of our methodology. The resulting sensing membrane are casted by dispersing the MIP in 2-nitrophenyl octyl ether plasticizer and embedding it within a PVC matrix containing sodium tetraphenyl borate as a lipophilic additive. The developed sensor responds to atrazine in the pH range of 2.8-3.3 over a wide concentration range of 1 × 10-8M to 1 × 10-5M & 1 × 10-5M to 1 × 10-1M with respective slopes of 29.2 mv & 58.7mV and a limit of detection of 1 × 10-9M. An impressive feature of this sensor lies in its swift response time, registering a rapid reaction within a mere 10s. Emphasize the sensor's commendable attributes of reproducibility, selectivity, and sensitivity underscoring its successful application in field monitoring.

Deciphering the energy storage mechanism of CoS2 nanowire arrays for High-Energy aqueous copper-ion batteries

Transition metal sulfide (TMs) offers ultra-high specific capacity through multi-electron transfer, showing promise for aqueous batteries. However, the poor cycling performance and the uncleared energy storage mechanism are restricted from further development. Herein, CoS2 nanowire arrays grown on carbon cloth (CoS2/CC) are proposed as binder-free and self-supporting electrodes for aqueous copper-ion batteries. The energy storage mechanism is clarified by a series of ex-situ tests: a multi-electron electrode reaction through a three-step reaction of CoS2 → CuS → Cu7S4 → Cu2S. Electrochemical results suggest that the CoS2/CC cathode exhibits excellent long cycle stability (capacity retention of 99.7 % after 1000 cycles at 10 A/g) along with high specific capacity (762.3 mAh g−1 at 1 A/g). The carbon cloth with stable three-dimensional (3D) conductive structure can not only offer high-speed pathways to promote the transfer of electrons but also inhibit the volume change. Meanwhile, CoS2 nanowire arrays with high surface-to-volume ratios can improve wettability of electrolyte and promote redox reactions. Furthermore, an advanced Zn-CoS2/CC hybrid ion aqueous battery reveals an energy density of 724 Wh kg−1 and an output voltage of 1.24 V, providing a promising strategy for the establishment of transition metal sulfide cathode in high-energy aqueous batteries.

Boosting Electrochemical Nitrate Reduction to Ammonia by Fe Doped CuO/Co3O4 Nanosheet/Nanowire Heterostructures.

The electrochemical nitrate reduction reaction (NO3-RR) is a novel green method for ammonia synthesis. The development of outstanding NO3-RR performance is based on reasonable catalyst. Metal oxides have garnered significant attention due to their exceptional electrical conductivity and catalytic properties. Doping serves as an effective strategy for enhancing catalyst performance due to its ability to change the electron cloud distribution and energy levels. In this study, we develop a heterojunction catalyst Fe doped copper oxide nanosheet and cobalt tetroxide nanowire growing on carbon cloth simultaneously (Fe-CuO@Co3O4/CC) via hydrothermal method. The well-designed Fe-CuO@Co3O4/CC has excellent NH3 yield (470.9 μmol h-1 cm-2) and Faraday efficiency (FE: 84.4%) at -1.2 V versus reversible hydrogen electrode (vs. RHE). The heterostructure increases the specific surface area of the catalyst, and the possibility of contact between the catalyst and NO3- ions, enhances the catalytic efficiency. In addition, the catalyst has excellent stability and can stably carry out the electrocatalytic nitrate reduction reaction (NO3-RR), which provides a way for further research on the high-efficiency reduction of nitrate.

The Positional Effect of an Immobilized Re Tricarbonyl Catalyst for CO2 Reduction.

The storage of renewable energy through the conversion of CO2 to CO provides a viable solution for the intermittent nature of these energy sources. The immobilization of rhenium(I) tricarbonyl molecular complexes is presented through the reductive coupling of bis(diazonium) aryl substituents. The heterogenized complex was characterized through ultra-visible, attenuated total reflectance, infrared reflection absorption spectroscopy, and X-ray photoelectron spectroscopy to probe the electronic structure of the immobilized complex. In addition, studies of cyclic voltammetry, controlled potential electrolysis, and electrochemical impedance spectroscopy were conducted to examine the CO2 reduction activity. The structure and CO2 reduction performance were compared with a previously reported immobilized rhenium(I) tricarbonyl molecular complex to probe the effect of varying the tethering of the aryl substituent from the 5,5'-position to the 4,4'-position of the 2,2'-bipyridine backbone. The immobilized complex on carbon cloth at the 4,4'-position provided excellent selectivity (FECO > 99%) and maximum TONCO and TOFCO values of 3359 and 0.9 s-1, respectively, without the addition of a Bro̷nsted acid source. A nonaqueous flow cell demonstrated the stability of this complex during a 5 h electrolysis. Tethering at the 4,4'-position, compared to the 5,5'-position, yielded lower overall activity for CO2 reduction and was attributed to the difference in growth morphology and formation of aggregations, due to Re-Re dimer formation and π-π stacking interactions within the metallopolymer matrix. For carbon cloth substrates, an optimized catalyst loading was determined to be 44.6 ± 11 nmol/cm2.

Oxygen vacancies enhancing hierarchical NiCo2S4@MnO2 electrode for flexible asymmetric supercapacitors

The limited energy density of supercapacitors hampers their widespread application in electronic devices. Metal oxides, employed as electrode materials, suffer from low conductivity and stability, prompting extensive research in recent years to enhance their electrochemical properties. Among these efforts, the construction of core–shell heterostructures and the utilization of oxygen vacancy (VO) engineering have emerged as pivotal strategies for improving material stability and ion diffusion rates. Herein, core–shell composites comprising NiCo2S4 nanospheres and MnO2 nanosheets are grown in situ on carbon cloth (CC), forming nanoflower clusters while introducing VO defects through a chemical reduction method. Density functional theory (DFT) results proves that the existence of VO effectively enhances electronic and structural properties of MnO2, thereby enhancing capacitive properties. The electrochemical test results show that NiCo2S4@MnO2-V3 exhibits excellent 1376 F g−1 mass capacitance and 2.06 F cm−2 area capacitance at 1 A g−1. Moreover, NiCo2S4@MnO2-V3//activated carbon (AC) asymmetric supercapacitor (ASC) can achieve an energy density of 39.7 Wh kg−1 at a power density of 775 W kg−1, and maintains 15.5 Wh kg−1 even at 7749.77 W kg−1. Capacitance retention is 73.1 % after 10,000 cycles at 5 A g−1, and coulombic efficiency reaches 100 %, demonstrating satisfactory cycle stability. In addition, the device’s excellent flexibility offers broad application prospects in wearable electronic applications.