Carbon Felt Substrate Research Articles

Research on the impact of polydopamine hydrogel electrodes with various doping methods on the performance of microbial fuel cells.

Microbial fuel cells (MFCs) have attracted considerable interest as a promising bioelectrochemical technology for directly converting chemical energy into electrical energy. However, their performance remains limited by the properties of anode materials and their interactions with microbial communities. In this study, PPy-MXene/PDA and PDA-PPy-MXene composite hydrogel electrodes (PMP and PPM) were fabricated on a conductive carbon felt substrate to systematically evaluate the influence of different PDA doping strategies on electrode performance. The PMP electrode exhibited a maximum power density of 3.62W/m2, which represented a 34.6% increase compared to the PPM electrode (2.69W/m2). Moreover, the protein content on the PMP electrode reached 38.05 ± 4.88mg/cm2, 3.79 times higher than that on the PPM electrode (10.05 ± 3.05mg/cm2). High-throughput sequencing of the 16S rRNA gene revealed that the relative abundance of Geobacter on the PMP electrode surface reached 73.66%, significantly higher than the 51.17% observed on the PPM electrode. These results are attributed to the PDA doping method involving secondary deposition on the electrode surface. This method optimizes the electron transfer pathways and significantly enhances the electrode's conductivity and electrochemical activity by altering the surface roughness of the electrode and increasing the content of hydrophilic functional groups. Consequently, it significantly promotes the enrichment of electroactive microorganisms and improves the efficiency of extracellular electron transfer. This study optimized PDA doping strategies to significantly enhance the electrochemical performance of MFCs, providing new insights and approaches for the rational design of high-performance bioelectrochemical electrodes.

Enhanced electricity generation and energy storage in a microbial fuel cell with a bimetallic-modified capacitive anode

Enhanced electricity generation and energy storage in a microbial fuel cell with a bimetallic-modified capacitive anode

In Situ Vertically Aligned MoS2 Arrays Electrodes for Complexing Agent‐Free Bromine‐Based Flow Batteries with High Power Density and Long Lifespan

AbstractBromine‐based flow batteries (Br‐FBs) are highly competitive for stationary energy storage due to their high energy density and cost‐effectiveness. However, adding bromine complexing agents (BCAs) to electrolytes slows down Br2/Br− reaction kinetics, causing higher polarization and lower power density of Br‐FBs. Herein, in situ vertically aligned MoS2 nanosheet arrays on traditional carbon felt substrates as electrodes to construct high power–density BCA‐free Br‐FBs are proposed. MoS2 arrays exhibit strong adsorption capacity to bromine, which helps the electrodes capture and retain bromine species. Even without BCAs, the battery self‐discharge caused by bromine diffusion is also inhibited. Moreover, the rate‐determining step of Br2/Br− reactions is boosted and the vertically aligned array structure provides sufficient sites, motivating Br2/Br− reaction kinetics and decreasing the battery polarization. The capacity retention rate of the BCA‐free Br‐FB based on MoS2 arrays‐based electrodes reaches 46.34% after the 24‐h standing test at 80 mA cm−2, meeting the requirements of practical applications. Most importantly, this BCA‐free Br‐FB exhibits a high Coulombic efficiency of 97.00% and an ultralong cycle life of 1000 cycles at a high current density of 200 mA cm−2. This work provides an available approach to developing advanced electrode materials for high power–density and long‐lifespan Br‐FBs.

High-kinetic and stable antimony anode enabled by tuning coordination environment for ultrafast aqueous energy storage

High-kinetic and stable antimony anode enabled by tuning coordination environment for ultrafast aqueous energy storage

Concentrated solar-thermal methane pyrolysis in a porous substrate: Yield analysis via infrared laser absorption

Concentrated solar-thermal methane pyrolysis in a porous substrate: Yield analysis via infrared laser absorption

Three-Dimensional PbO2-Modified Carbon Felt Electrode for Efficient Electrocatalytic Oxidation of Phenol Characterized with In Situ ATR-FTIR

A three-dimensional (3D) electrode was successfully fabricated by coating carbon felt substrate with PbO2 using an electrodeposition method. Compared with the conventional planar Ti/SnO2–Sb/PbO2 electrode, the CF/PbO2 electrode displayed superior electrocatalytic performance for the degradation of phenol, with an 11.2 times higher rate constant. The improved performance was due to its larger active surface area, enrichment of phenol on the surface due to adsorption, and enhanced mass transfer with the porous 3D structure. It also exhibited an 11.4 times higher current efficiency and a 9.1 times lower energy consumption due to the superior electrocatalytic activity and a higher oxidation potential to hinder oxygen evolution. Moreover, the generation rate of •OH from CF/PbO2 was 1.3 times higher than that of the Ti/SnO2–Sb/PbO2 electrode. The surface chemistry on the CF/PbO2 electrode during phenol degradation was explored by in situ attenuated total reflection–Fourier transform infrared (ATR-FTIR) characterization, with aromatic intermediates and carboxylic acids identified as key reaction intermediates. This composite electrode also presented excellent long-term stability and durability and negligible leaching of Pb cation, demonstrating as a promising electrode for the electrocatalytic degradation of refractory pollution in wastewater treatment.

A high-capacity 1,2:3,4-dibenzophenazine anode integrated into carbon felt for an aqueous organic flow battery in alkaline media

A novel organic anode with high mass loading is prepared by integrating 1,2:3,4-dibenzophenazine into a carbon felt substrate via a DES-assisted preparation approach for a high-capacity and long-life alkaline aqueous organic flow battery.

Introducing an Electrochemically Driven Proton Concentration Process for CO2 Capture

An electrochemically driven proton concentration process was developed for the capture of carbon dioxide (CO2) that was based on modulation of the proton concentration in an electrochemical cell by a proton intercalating MnO2 electrode. The pH sensitivity of CO2 hydration was leveraged such that CO2 was absorbed as bicarbonate and carbonate ions at high pH values and desorbed as gas at low pH values. A comprehensive thermodynamic model developed to determine the speciation, electrochemical performance, and energetics required to desorb CO2 captured from a flue gas was validated by chemical and electrochemical measurements, with very good agreement between simulated and experimental results. The electrochemical work requirement for the proposed proton concentration process to desorb CO2 captured from a flue gas stream was estimated to be 33.2 kJe/molCO2, suggesting that this process is competitive with other electrochemical-based approaches (with energetics ranging from 31.3 to 49 kJe/molCO2). The MnO2 electrode was successfully synthesized using a coprecipitation method followed by casting on either carbon cloth or carbon felt substrate. The fabricated electrodes were characterized using X-ray photoelectron spectroscopy to assess their chemical state, and the formation of MnO2 was confirmed. The capacitance behavior of the electrodes, which is proportional to their electrochemical performance, was evaluated using cyclic voltammetry (CV). The fabricated electrodes were also tested in a symmetrical electrochemical cell with a constant potential applied across the cell. The generated current was effectively translated into proton intercalation/deintercalation reactions through reversible cycles, resulting in modulated proton concentrations in the anode and cathode chambers. The demonstrated model and experimental data suggest that this proton concentration process could be an attractive electrochemical-based route for CO2 capture.

High performance yeast-based microbial fuel cells by surfactant-mediated gold nanoparticles grown atop a carbon felt anode

High performance yeast-based microbial fuel cells by surfactant-mediated gold nanoparticles grown atop a carbon felt anode

PEDOT:PSS-based Multilayer Bacterial-Composite Films for Bioelectronics

Microbial electrochemical systems provide an environmentally-friendly means of energy conversion between chemical and electrical forms, with applications in wastewater treatment, bioelectronics, and biosensing. However, a major challenge to further development, miniaturization, and deployment of bioelectronics and biosensors is the limited thickness of biofilms, necessitating large anodes to achieve sufficient signal-to-noise ratios. Here we demonstrate a method for embedding an electroactive bacterium, Shewanella oneidensis MR-1, inside a conductive three-dimensional poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) matrix electropolymerized on a carbon felt substrate, which we call a multilayer conductive bacterial-composite film (MCBF). By mixing the bacteria with the PEDOT:PSS precursor in a flow-through method, we maintain over 90% viability of S. oneidensis during encapsulation. Microscopic analysis of the MCBFs reveal a tightly interleaved structure of bacteria and conductive PEDOT:PSS up to 80 µm thick. Electrochemical experiments indicate S. oneidensis in MCBFs can perform both direct and riboflavin-mediated electron transfer to PEDOT:PSS. When used in bioelectrochemical reactors, the MCBFs produce 20 times more steady-state current than native biofilms grown on unmodified carbon felt. This versatile approach to control the thickness of bacterial composite films and increase their current output has immediate applications in microbial electrochemical systems, including field-deployable environmental sensing and direct integration of microorganisms into miniaturized organic electronics.

A novel flexible electrode of Fe3O4-embedded in carbon felt as binder-free anode for lithium-ion batteries

The paper reports a novel flexible electrode based on Fe3O4-embedded in carbon felt via a facile hydrothermal method. As a binder-free anode for Lithium ion batteries, it exhibits a stable reversible capacity of 590 mA h g−1 after 100 cycles at a current density of 200 mA g−1, together with modified rate capability. The improved lithium storage properties can be attributed to the synergistic effect between nano-sized embedded Fe3O4 and carbon felt substrate. The elastic carbon fibers are beneficial for alleviating the volume expansion of Fe3O4 during continuous discharge/charge cycling. Besides, the designed structure leads to shorter ion transport path and better diffusion of electrolyte, resulting in the enhanced rate capacity and reversible capacity. The structure, morphology and the electrochemical performances of Fe3O4/carbon felt electrode for flexible Lithium ion batteries are analyzed in details.

Composite, multilayer and three-dimensional substrate supported tin-based electrodeposits from methanesulphonic acid

Tin and tin–alloy deposits enjoy many applications in the electronics, tribology and engineering industries with potential applications as electrodes for lithium batteries and as electrocatalyst coatings. Methanesulphonic acid (MSA) has become a favoured electrolyte due to its environmental benefits and ability to offer a vehicle for many metal alloy, conductive polymer and composite coatings. A number of emergent uses require less common compositions or structures of alloy, polymer or composite deposits. This paper concisely provides diverse examples of modern tin-containing deposits from aqueous MSA, including Sn–Cu alloys having a very wide composition together with a wide range of colours (golden-yellow–dark-brown) and surface finishes, a Sn–Cu composite deposit containing ceramic, protonated titanium oxide nanotubes for batteries, a tin–copper–bismuth ternary alloy and tin deposits supported on an inert reticulated vitreous carbon or carbon felt substrate to provide a porous, three-dimensional tin surface for electrocatalysis and batteries. The importance of controlled current distribution and electrode/electrolyte movement is illustrated by the use of the rotating disc electrode, rotating cylinder electrode and rotating cylinder Hull cell.

Electrophoretic Deposition of Nanoparticles into Three-Dimensional Felt As an Electrocataylst for the Solar Sulfur Ammonia Thermochemical Cycle

The penetration and coating of nanoparticles by electrophoretic deposition (EPD) into three-dimensional substrates was studied. Specifically, EPD of cobalt ferrite nanoparticles (20 nm) was investigated as a possible electrocatalyst to improve the kinetically slow anodic reaction of the oxidation of ammonium sulfite to ammonium sulfate in the hydrogen production sub-cycle of the solar sulfur-ammonia thermochemical water-splitting process. The primary goals were to uniformly penetrate and coat nanoparticles into 3D substrates by electrophoretic deposition and then to test their electrocatalytic activity by linear sweep voltammetry in 2 M ammonium sulfite. Electrophoretic deposition of cobalt ferrite nanoparticles from five bath compositions was performed on the following substrates: aluminum foil, graphite paper, 3 mm carbon felt, and 6 mm graphite felt. The bath compositions were 2 g/L of cobalt ferrite nanoparticles in 90/10 vol. % water/isopropanol with 1 mM (CHigh) or 0.05 mM (CLow) of hexadecyltrimethlyammonium bromide (CTAB), in 100% ethanol (E), in 100% acetylacetone (AA), and 100% acetylacetone with 0.2 wt. % polyethylenimine (AA-PEI). For electrophoretic deposition, a constant voltage was applied from 20 V to 128 V for a deposition time from 1 to 13 minutes. The zeta potential was measured to be 23 1 mV at pH of 6 for CHigh bath and 13 2 mV at pH 5 for E bath. Dry and wet adhesion of EPD deposits on aluminum was performed to determine adherence of nanoparticles to the substrate both after deposition and during the electrochemical process. Nanoparticles had good adherence to the substrate. To determine if nanoparticles could penetrate into 3D felt substrates by EPD, the ratio of Peclet number to Damköhler number (ratio of electrophoretic velocity to local deposition rate) was calculated to be greater than 1000, which indicated full penetration. Scanning electron microscopy (SEM) of the top and middle of the EPD deposits was used to examine the nanoparticle penetration and deposit morphology. It was confirmed by SEM images that there was full penetration and coating of nanoparticles into the 3 mm carbon felt and the 6 mm graphite felt from the 100% ethanol bath. The electrocatalytic activity of the EPD deposits on aluminum foil, graphite paper, 3 mm carbon felt, and 6 mm graphite felt substrates were analyzed by linear sweep voltammetry at 50 mV/s for the oxidation of 2 M ammonium sulfite. For the 3 mm carbon felt substrates, the highest electrochemical activity occurred on EPD deposits from the AA-PEI bath and then E bath. The highest electrochemical activity of the EPD deposits on 6 mm graphite felt occurred from the bath chemistries in decreasing order: CLow, AA-PEI, and E. The EPD deposit on 6 mm graphite felt from CLow bath obtained the highest electrochemical activity of all the deposits. For the 3 mm carbon felt, the ratio of current density of deposit compared to blank substrate ranged from 4 to 8 from E bath. The ratio of current density of EPD deposit on graphite paper and 6 mm graphite felt from E bath compared to blank substrate was about 1.6. The 3 mm carbon felt EPD deposits from AA-PEI bath ranged from 9 to 14, for the ratio of current density of the deposit compared to the blank substrate. EPD deposits from AA-PEI bath had a ratio of current density of deposit to blank substrate of 1.9 for deposits on aluminum foil, graphite paper, and 6 mm graphite felt. Overall, EPD was successful as a method to penetrate and coat cobalt ferrite nanoparticles up to 6 mm thick 3D felt. EPD deposits from AA-PEI bath improved the electrochemical activity compared to the blank substrate more than EPD deposits from E bath. But the EPD deposits from E bath were thin and uniform as well as deposited at much lower voltages compared to deposits from AA-PEI bath. EPD deposits from 3 mm carbon felt resulted in the largest improvement in electrochemical activity compared to the blank substrate from both E and AA-PEI bath. However, EPD deposits into 6 mm graphite felt had the highest electrochemical activity from all of the deposits. The EPD deposits with the highest electrochemical activity into 6 mm graphite felt in decreasing order were CLow, AA-PEI and E. The EPD conditions for these deposits were 40 V for 1 min from CLow resulting in current density of 75 mA/cm2, 127 V for 4 min from AA-PEI resulting in current density of 60 mA/cm2, and 40 V for 1 min from E resulting in current density of 38 mA/cm2.

SEM Analysis of Electrophoretically-Deposited Cobalt Ferrite Films

Cobalt ferrite nanoparticles (20 nm) were synthesized and electrophoretically deposited onto aluminum foil, graphite paper, and carbon felt (3 mm thickness) from a 100% ethanol bath. Linear sweep voltammetry was used to test the electrocatalytic activity of the deposits relative to blank substrates for the oxidation of ammonium sulfite to ammonium sulfate in a proposed sulfur ammonia (SA) water-splitting solar thermochemical cycle. Subsequently, scanning electron microscopy (SEM) was used to study the morphology of the cobalt ferrite films. The effects of electrophoretic deposition conditions on deposit morphology and the effects of deposit morphology on electrochemical activity in 2 M ammonium sulfite were investigated. EPD on aluminum and graphite paper was performed such that particles were deposited on only one side of the substrate. For the 3 mm thick carbon felt, particles were deposited on both sides of the substrate to improve deposit uniformity throughout the sample. Both deposition time (0-10 minutes) and deposition current (0-16 mA) were varied to analyze their effects on the resulting deposit films for all substrates. For the EPD conditions studied, a critical deposit thickness was found for graphite paper and carbon felt for maximum electrochemical current density, where additional deposited particles reduced the electrocatalytic activity of the deposits. This thickness was estimated to be 3 particle layers for the graphite paper substrate. At this thickness, the deposit had a 5.5 fold increase in activity relative to a blank graphite paper substrate. SEM micrographs showed that the deposit uniformly covered the substrate and had noticeable cracking. For the carbon felt, the critical deposit thickness was observed to be approximately 1-2 particle layers via SEM analysis. Moreover, SEM images showed that the deposit was a uniform film with no cracking. At this thickness, the deposit had a 4.3 fold increase in activity compared to a blank carbon felt substrate.

Polypyrrole-coated hierarchical porous composites nanoarchitectures for advanced solid-state flexible hybrid devices

Polypyrrole-coated hierarchical porous composites nanoarchitectures for advanced solid-state flexible hybrid devices

Fe-catalyzed growth of one-dimensional α-Si3N4 nanostructures and their cathodoluminescence properties

Preparation of nanomaterials with various morphologies and exploiting their novel physical properties are of vital importance in nanoscientific field. Similarly to the III-N compound semiconductors, Si3N4 nanostructures also could be potentially used for making optoelectronic devices. In this paper, we report on an improved Fe-catalyzed chemical vapour deposition method for synthesizing ultra-long α-Si3N4 nanobelts along with a few nanowires and nanobranches on a carbon felt substrate. The ultra-long α-Si3N4 nanobelts grew via a combined VLS-base and nanobranches via a combined double-stage VLS-base and VS-tip mechanism, as well as nanowires via VLS-tip mechanism. The three individual nanostructures showed variant optical properties as revealed by a cathodoluminescence spectroscopy. A single α-Si3N4 nanobelt or nanobranch gave a strong UV-blue emission band as well as a broad red emission, whereas a single α-Si3N4 nanowire exhibited only a broad UV-blue emission. The results reported would be useful in developing new photoelectric nanodevices with tailorable or tunable properties.

Synthesis, Characterization and Evaluation of Pb Electroplated Carbon felts for Achieving Maximum Efficiency of Fe-Cr Redox Flow Cell

To catalyze Cr(III)/Cr(II) redox couple, Pb was used as candidate catalysts. Pb has a remarkable behavior on reduction and oxidation of chromium couple to enhance the performance of Fe-Cr redox flow cell. In the present investigation catalyzed carbon felt substrates were used as electrodes on negative side which were electrochemically plated/ loaded with Pb from 0.05g to 1.2g. The cell comprising 0.8 g Pb loaded felt has shown 100% Chromium reduction efficiency, 98% coulombic efficiency and zero hydrogen gassing at 32oC for 15 cycles of charge and discharge. 5liters of 1.3N FeCl2 in 2N HCl as catholyte, 1.3N CrCl3 in 2N HCl as anolyte containing 0.05N BiCl3 as additive were used as electrolytes. The cell operated with Nafion-117 PFSA membrane. 100 cm2 GFA grade carbon felts with 3mm thickness were utilized as electrodes at a current density of 50 mA/ cm2.

Thermal Annealing and Electrochemical Purification of Multi-Walled Carbon Nanotubes Produced by Camphor/Ferrocene Mixtures

Multi-walled carbon nanotubes (MWCNT) were obtained by pyrolysis of camphor/ferrocene mixtures, at different concentrations of ferrocene, on quartz, polished silicon and carbon felt substrates. A detailed study by electron microscopy, Raman spectroscopy, X-ray diffraction and thermogravimetric analysis was carried out to determine the purity degree of MWCNTs. Thermal annealing under vacuum and electrochemical purification were used for iron removal. The thermal annealing brings improvement on crystalline structure of MWCNTs, besides iron elimination from internal structure of the tubes, while the electrochemical treatments remove efficiently the iron from MWCNT surface.

Electrochemical insertion of lithium into a doped diamond film grown on carbon felt substrates

Electrochemical insertion of lithium into a doped diamond film grown on carbon felt substrates

Fabrication of Composite Films Containing Zirconia and Cationic Polyelectrolytes

Composite films were prepared by electrophoretic deposition of poly(ethylenimine) or poly(allylamine hydrochloride) combined with cathodic precipitation of zirconia. Films of up to several micrometers thick were obtained on Ni, Pt, stainless-steel, graphite, and carbon-felt substrates. When the concentration of polyelectrolytes in solutions and the deposition time were varied, the amount of the deposited material and its composition can be varied. The electrochemical intercalation of yttria-stabilized zirconia particles into the composite films has been demonstrated. Obtained results pave the way for the electrodeposition of other polymer-ceramic composites. The deposits were studied by thermogravimetric analysis, X-ray diffraction analysis, scanning electron microscopy, and atomic force microscopy. The mechanisms of deposition are discussed.