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[Display omitted] • Free-standing composite papers of SFCP@PANI were prepared. • The free-standing SFCP@PANI-2 paper was directly utilized as supercapacitive electrodes. • The SFCP@PANI-2 demonstrated an enhanced electrochemcial capacitive performance. Free-standing composite papers of SFCP@PANI were prepared by in situ polymerization of aniline on the surface of sisal fiber carbon paper (SFCP). The SFCP@PANI papers can be directly built into electrodes without the need for any binders or conductive agents. SFCP@PANI-2 exhibits excellent electrochemical performance in the three-electrode system and the coin-type symmetric supercapacitor (SSC), which indicates that it may be a promising electrode material for supercapacitor. [ABSTRACT FROM AUTHOR]

The combination of electrochemistry and mass spectrometry is a powerful analytical tool for studying redox reaction mechanisms and identifying products or intermediates. However, the previously reported devices all require bespoke fabrication and are too complicated to be assembled and used by others. Crucially, the long ion transport distance and small spray volumes make it difficult to capture the short-lived intermediates. We present a practical mass spectrometric method in which surface-modified carbon fiber paper is innovatively applied to detect electrogenerated intermediates. Treating carbon fiber paper with dilute nitric acid removes its surface impurities, enhancing the capability of electro-redox. Electrospray ionization and redox reaction occur simultaneously on the tip of the paper. Transient electro-redox species generate and transfer into gas phase as soon as the appearance of spray. Rapid transport of quantities of electrogenerated ions to the mass spectrometer inlet makes it possible for mass spectrometric identification on the millisecond scale. The short-lived radical cations and iminium ions were successfully captured, reflecting the starting step of the cross-dehydrogenation coupling reaction. The real-time oxidation and online functionalization reactions of tertiary amines were achieved using this device without additional oxidants and electrolytes. In this way we could achieve in-depth mechanistic understanding and rapid screening of serial reactions. [Display omitted] • Treating carbon fiber paper with dilute nitric acid enhances the capability of detecting electrogenerated intermediates. • A-CFPSI permits the real-time monitoring of electrochemical reaction intermediates on the millisecond scale. • No additional electrolytes and oxidants are required, avoiding interference with the mass spectrum. • A-CFPRSI can be used for rapid screening of electrochemical reactions and mechanism researches. [ABSTRACT FROM AUTHOR]

[Display omitted] • It is easier and cheaper to produce sisal fiber carbon paper supercapacitor electrodes in various shapes. • The free-standing SFCPs were directly utilized as supercapacitive electrodes. • SFCP-900 exhibited relatively good electrochemical properties in supercapacitor. Sisal Fiber Carbon Papers (SFCPs) with high specific surface area was obtained using a simple hydrothermal, pressing and carbonization method. The effects of calcination temperature on morphology, structure, pore structure and electrochemical properties of SFCPs were systematically studied. The free-standing SFCPs were directly utilized as supercapacitive electrodes, and the results revealed that the SFCPs calcinated at 900 °C (SFCP-900) exhibit a better specific capacity than SFCP-800 and SFCP-1000. These results suggested that the SFCP-900 has potential applications in supercapacitors. [ABSTRACT FROM AUTHOR]

A simple synthetic chemical process to produce metal oxide loaded carbon papers was developed using bacterial cellulose gel, which consisted of nanometer-sized fibrous cellulose and water. Metal ions were successfully impregnated into the gel via aqueous solution media before drying and carbonization methods resulting in metal oxide contents that were easy to control through variations in the concentration of aqueous solutions. The papers loaded by molybdenum oxides were characterized as pseudocapacitor electrodes preliminary, and the large redox capacitance of the oxides was followed by a conductive fibrous carbon substrate, suggesting that a binder and carbon black additive-free electrode consisting of metal oxides and carbon paper was formed. [ABSTRACT FROM AUTHOR]

This study analyzed theoretically the effects of a carbon paper (CP)-based electrode on the performance of a vanadium redox flow battery (VRFB). Compared to conventional carbon felt-based electrode materials, the CP-based electrode showed superior characteristics in facilitating the redox reactions of VO 2+ / VO 2 + and V 2+ / V 3+ couples, such as better electrochemical activity and higher electronic conductivity. A three-dimensional, non-isothermal VRFB model developed in a previous study was applied to a range of single cell structures equipped with CP-based electrodes and flow channels in the current collectors. The model was then validated using the experimental data measured under the CP- and channel-based VRFB geometries. The model successfully captured the experimental trend that showed a higher discharging performance with increasing number of CP layers used for each electrode. The simulation results clearly showed that the activation overpotentials in the electrodes were reduced significantly using more CP layers, which dominated over the effects of increased mass transport limitation of vanadium ions due to the thicker electrode. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nanowall films were synthesized by plasma enhanced hot filament chemical vapour deposition on carbon paper, a three dimensionally structured material. The micro-structured nature of the carbon paper, which is composed of an irregular and open mesh of carbon fibres, allowed one to determine the microstructure of the carbon nanowalls both at the tip and at the fibre–nanowall base interface. The number of graphenes which pile up to form the structure of a single nanowall ranges from 1 to 2 at the tip up to several 10s at the base, making this material suitable to study and eventually exploit the electronic properties of graphenes on a macroscopic scale. Such material is promising for electrochemical applications. [Copyright &y& Elsevier]

Abstract: In situ grown carbon nanotubes (CNTs) on carbon paper as an integrated gas diffusion layer (GDL) and catalyst layer (CL) were developed for proton exchange membrane fuel cell (PEMFC) applications. The effect of their structure and morphology on cell performance was investigated under real PEMFC conditions. The in situ grown CNT layers on carbon paper showed a tunable structure under different growth processes. Scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) demonstrated that the CNT layers are able to provide extremely high surface area and porosity to serve as both the GDL and the CL simultaneously. This in situ grown CNT support layer can provide enhanced Pt utilization compared with the carbon black and free-standing CNT support layers. An optimum maximum power density of 670mWcm−2 was obtained from the CNT layer grown under 20cm3 min−1 C2H4 flow with 0.04mgcm−2 Pt sputter-deposited at the cathode. Furthermore, electrochemical impedance spectroscopy (EIS) results confirmed that the in situ grown CNT layer can provide both enhanced charge transfer and mass transport properties for the Pt/CNT-based electrode as an integrated GDL and CL, in comparison with previously reported Pt/CNT-based electrodes with a VXC72R-based GDL and a Pt/CNT-based CL. Therefore, this in situ grown CNT layer shows a great potential for the improvement of electrode structure and configuration for PEMFC applications. [Copyright &y& Elsevier]

Abstract: The reductive removal of haloacetic acids (HAAs) in a three-dimensional electrochemical continuous reactor with Pd-granular activated carbon (Pd-GAC) particles as fixed filler and Pd-modified carbon paper (Pd-C) as cathode was studied in this research. Pd-C electrode was prepared from PdCl2 via electrodeposition onto carbon paper. Pd-GAC particles were prepared by the impregnation of Pd2+ ions onto GAC. Efficient electrocatalytic reduction of HAAs in this reactor was exhibited. Effects of current density, initial HHAs concentration, and hydraulic retention time on the HHAs removal were investigated. Under the current density of 0.3 mA/cm2, HAAs with initial concentration of 120 μg/L were reduced to be less than 60 μg/L with hydraulic retention time of 20 min. Electron transfer and HAAs diffusion both played an important role in controlling the electro-reduction process under the conditions of current density less than 0.6 mA/cm2 with an initial HAAs concentration ranging from 120 to 600 μg/L. However, the HAAs diffusion became the primary rate-limiting step when the current density was higher than 0.6 mA/cm2. The Pd0 and Pd2+ species were detected by X-ray photoelectron spectroscopy. The stability of the electrochemical reactor in the reduction removal of HAAs was also exhibited. [Copyright &y& Elsevier]

Abstract: Although mitochondria have been used for bio-electrochemistry for over 5 years, little is known about their direct electrochemistry mechanism. This paper focuses on developing a better understanding of the electron transfer mechanism of mitochondria from three different organisms at carbon electrodes. Yeast, potato and bovine mitochondria have been successfully isolated and immobilized onto Toray paper electrodes via vapor deposited silica. Organelle-modified electrodes were first characterized using cyclic voltammetry. Similar electrochemical signals were obtained for all organisms. Direct electron transfer was observed when a metabolite of the Krebs cycle was present in the buffer solution. Control experiments based on the immobilization of two electron carriers contained in mitochondria, cytochrome c and a quinone (coenzyme Q 10), tend to show the electron transfer mechanism to the carbon material comes from the quinone pool of the organelles. As quinones are known to be pH-dependent, we further investigated the response of the electrochemical signal of the three isolated mitochondria and the two electron carriers separately. The half wave potentials obtained from the organelles appeared to be pH-dependent and their variations are comparable to coenzyme Q 10 rather than cytochrome c. Finally, extraction of both the cytochrome c and the quinone pool from intact mitochondria was performed to validate our hypothesis that direct electrochemistry of mitochondria happens via the quinone pool. Electrochemistry of immobilized quinone-depleted mitochondria validated the hypothesis that the mitochondria are communicating with the electrodes through the quinone pool. [Copyright &y& Elsevier]

Abstract: This article reports a facile microwave-assisted approach to synthesize Pt catalysts on carbon nanotube (CNT)/carbon paper (CP) composite through catalytic chemical vapor deposition. The Pt deposits, with an average size of 3–5 nm were uniformly coated over the surface of oxidized CNTs. The electrochemical activity and stability of the Pt–CNT/CP electrode were investigated in 1 M H2SO4 using cyclic voltammetry (CV) and ac electrochemical impedance spectroscopy. The Pt catalysts showed not only fairly good electrochemical activity (electrochemically active surface area) but also durability after a potential cycling of >1000 cycles. The analysis of ac impedance spectra associated with equivalent circuit revealed that the presence of CNTs significantly reduced both connect and charge transfer resistances, leading to a low equivalent series resistance ˜0.22 Ω. With the aid of CNTs, well-dispersed Pt catalysts enable the reversibly rapid redox kinetic since electron transport efficiently passes through a one-dimensional pathway. Thus, the CNTs do not only serve as carbon support, they also charge transfer media between the Pt catalysts and the gas diffusion layer. The results shed some light on the use of CNT/CP composite, offering a promising tool for evaluating high-performance gas diffusion electrodes. [ABSTRACT FROM AUTHOR]

A microporous PTFE/carbon sublayer between the carbon paper and the catalyst layer played a crucial role in PEM fuel cells. Such a layer reduced the difference among different carbon paper types made by different manufacturers or by the same manufacturer at different times. When such a sublayer was present, the carbon paper seemed to function merely as a support that provided the mechanical strength for the sublayer. A sublayer was extremely useful if the carbon paper was prone to flooding. Sublayers of different thickness containing 24, 35 and 45% PTFE were tested. A four-cell stack could operate stably at a current density of 145 mA/cm2 using unhumidified air and hydrogen when sublayered carbon paper was employed. [Copyright &y& Elsevier]

Abstract: PEM fuel cells are increasingly designed to operate at high current densities. At these densities, mass transport limitations become very significant, but they are not well understood, with many modeling studies but few experimental observations. The use of accurate transport coefficients to simulate the mass transport at high current densities is crucial. In this study, experimental measurements have been carried out to determine the effective diffusion coefficient in the carbon paper gas diffusion layer that is commonly used in PEM fuel cells. It was found that almost all the existing theoretical models significantly overpredict the effective diffusion coefficient by as much as 4–5 times; thus, underestimating the transport limitations considerably. Further, the effects of temperature, Teflon treatment for hydrophobicity and porosity on the effective diffusion coefficient were investigated. It was found that temperature does not affect the overall diffusibility of the gas. The diffusibility is decreased with the increase of Teflon treatment and decrease in porosity. Further work on better understanding the diffusion process in the gas diffusion layer is under way. [Copyright &y& Elsevier]

The first rechargeable aqueous Na–air battery has been fabricated, and its electrochemical properties and reversibility are reported herein. The charge–discharge properties of the battery were tested using both Vulcan XC72R- and Pt/C-coated carbon paper as the air electrode. Pt/C-coated carbon paper exhibited a voltage efficiency of 84.3%, whereas, for Vulcan XC72R-coated carbon paper and uncoated carbon paper, the observed efficiencies were 78.0% and 72.4%, respectively. Use of Pt/C-coated carbon paper led to a high and stable discharging voltage of 2.85 V. The reported rechargeable aqueous Na–air battery is a potential candidate for high energy density batteries in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel nanomaterial toward (CuCo/CP) electrochemical water splitting. • Facile method for Copper-Cobalt (CuCo) supported on carbon paper (CuCo/CP) composition. • The electrochemical activation of electrode led to improvement of OER and HER kinetics. • Tafel slopes has been calculated for CoCu/CP is 97.7 mV dec−1. • CuCo/CP an emerging material for different energy applications. Electrochemical water splitting is one of the most appealing approaches to produce Hydrogen as a sustainable energy resource. The efficiency of Hydrogen evolution reaction (HER) and Oxygen evolution reaction (OER) largely depends on the activity and stability of any elctrocatalyst. Herein, we have employed a facile and reproducible electrodeposition coating method to synthesize bi-metallic Copper-Cobalt (CuCo) containing electrocatalyst supported on carbon paper (CuCo/CP) for electrochemical splitting of water in neutral medium. We have accomplished superior and improved HER and OER electrocatalytic activity, regardless of lower activity of Cu toward HER and OER. The unique structure and synergistic effect of CuCo/CP displayed better electrocatalytic activity with a low overpotential of 450 mV at 10 mA.cm−2 toward HER and just 80 mV at 10 mA.cm−2 toward Oxygen evolution reaction than other Cu containing electrocatalysts. Moreover, the durability of synthesized electrocatalyst at high applied current density ensure the stable nature of the catalyst. The present study may pave the way for the rational design of electrocatalysts for efficient Oxygen and Hydrogen production applications. [ABSTRACT FROM AUTHOR]

Abstract: A novel mesoporous carbon (MC) modified carbon paper has been constructed using layer-by-layer self-assembly method and is used as anode in an air-cathode single-chamber microbial fuel cell (MFC) for performance improvement. Using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), we have demonstrated that the MC modified electrode exhibits a more favorable and stable electrochemical behavior, such as increased active surface area and enhanced electron-transfer rate, than that of the bare carbon paper. The MFC equipped with MC modified carbon paper anode achieves considerably better performance than the one equipped with bare carbon paper anode: the maximum power density is 81% higher and the startup time is 68% shorter. CV and EIS analysis confirm that the MC layer coated on the carbon paper promotes the electrochemical activity of the anodic biofilm and decreases the charge transfer resistance from 300 to 99Ω. In addition, the anode and cathode polarization curves reveal negligible difference in cathode potentials but significant difference in anode potentials, indicating that the MC modified anode other than the cathode was responsible for the performance improvement of MFC. In this paper, we have demonstrated the utilization of MC modified carbon paper to enhance the performance of MFC. [Copyright &y& Elsevier]

Abstract: Microbial electrolysis cell (MEC) provides a sustainable way for hydrogen production from organic matters, but it still suffers from the lack of efficient and cost-effective cathode catalyst. In this work carbon paper coated with Pd nanoparticles was prepared using electrochemical deposition method and used as the cathodic catalyst in an MEC to facilitate hydrogen production. The electrode coated with Pd nanoparticles showed a lower overpotential than the carbon paper cathode coated with Pt black. The coulombic efficiency, cathodic and hydrogen recoveries of the MEC with the Pd nanoparticles as catalyst were slightly higher than those with a Pt cathode, while the Pd loading was one order of magnitude less than Pt. Thus, the catalytic efficiency normalized by mass of the Pd nanoparticles was about fifty times higher than that of the Pt black catalyst. These results demonstrate that utilization of the cathode with Pd nanoparticles could greatly reduce the costs of the cathodic catalysts when maintaining the MEC system performance. [Copyright &y& Elsevier]

Abstract: In this communication we show that the achievable maximum current density for mature wastewater-based microbial biofilms is strongly dependent on the electrode material and the operation temperature. On graphite and polycrystalline carbon rods, the catalytic current of about 500μAcm−2 (projected surface area) at 30°C was achieved. Carbon fiber veil or carbon-paper based materials, having a large microbially-accessible surface gave a projected current density ∼40% higher than on graphite rod. In contrast, the biofilm cannot form well on graphite foil. Elevating the temperature from 30 to 40°C increased current density by 80% on graphite rod anodes. Interestingly, the formal potential of the active site (−0.12V (vs. standard hydrogen electrode (SHE))) is similar to all electrocatalytically active microbial biofilms and to that found for Geobacter sulfurreducens in previous studies. In addition, the real surface area values measured by BET surface area technique cannot provide a reasonable explanation for suitability of an electrode material for the formation of electrochemically active biofilm. [Copyright &y& Elsevier]