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Here, we report the investigation of carbon black as a cost-effective nanomodifier of thermoplastic polyurethane-based 3D printed electrodes for enhancing their electrochemical performances. The sensor was produced by scratching the working electrode with sandpaper, followed by the deposition of carbon black dispersion by drop casting. The morphological characterisation was carried out, showing the presence of a homogeneous coating of carbon black with a typical rough and spongy structure. Additionally, the electrochemical characterisation using electrochemical impedance spectroscopy highlighted the advantage of using carbon black as a nanomodifier of the working electrode surface after printing by obtaining the resistance of charge transfer equal to 327 ± 43 kΩ and 1.45 ± 0.06 kΩ for bare electrode and carbon black-modified electrode, respectively. When tested in cyclic voltammetry using ferro/ferricyanide, uric acid, dopamine, ascorbic acid, and free chlorine as target electroactive compounds, we demonstrated that the presence of carbon black cast onto the working electrode surface transformed the electrode from non-responsive to responsive electroanalytical tool. The analytical features of the developed responsive sensor were assessed for the detection of free chlorine in tap water with a linearity of 0.2–20 ppm and a limit of detection equal to 0.01 ppm. The accuracy was evaluated by spiking tap water samples with free chlorine concentrations equal to 0.5, 1, and 5 ppm, obtaining recovery percentages of (103 ± 2)%, (104 ± 3)%, and (95 ± 3)%, respectively. Additionally, the sustainability (electro)chemical-free pre-treatment thermoplastic polyurethane-based 3D printed electrodes modified with carbon black were evaluated by the White Analytical Chemistry principles. The advantages of 3D printed sensors modified with carbon black by drop casting were demonstrated, in terms of both the electrochemical performances and sustainable aspect, enlarging the use of carbon black as a nanomodifier to the 3D printed electrodes, beyond the 2D printed electrodes. [Display omitted] [ABSTRACT FROM AUTHOR]

The need to deliver high performant and miniaturised electrochemical sensors has boosted the use of carbon nanomaterials as smart modifiers of working electrode surface. Among the carbon nanomaterials, the common and cost-effective carbon black has recently attracted the attention from the scientific community for its outstanding features as electrode nanomodifier for analyte detection. Herein, we report the structural and morphological characterisation of several types of carbon blacks, namely HP 160, HS20, MTN 990, N115, N220, N375, N660, PL6, Super P, and XE2B, by means of Raman spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses. Furthermore, the electrochemical characterisation of screen-printed electrodes modified with these carbon blacks was carried out by cyclic voltammetry and electrochemical impedance spectroscopy with ferro/ferricyanide as redox probe, highlighting the advantage to use carbon black as nanomodifier in respect to the bare electrode. Among several tested carbon black types, the lowest peak-to-peak separation and resistance to electron transfer values were achieved using screen-printed electrodes modified with CB N115, N375, HP 160 and PL6. The electrodes modified with these types of CB were successively tested in cyclic voltammetry towards epinephrine, benzoquinone, ascorbic acid, cysteine, catechol, and caffeic acid, observing a remarkable improvement of electrochemical performances in respect to the bare electrode, even when the amperometric mode was used. The results obtained demonstrated that several types of CB can remarkably improve the electrochemical performances of the sensors in terms of the decrease of applied potential or peak-to-peak separation, the improvement of the peak intensity, and the decrease of the resistance of the electron transfer due to several key features, including nanodimensions, the onion-like carbon structure, and the high number of defect sites. Image 1 [ABSTRACT FROM AUTHOR]

• Development of flexible nanocellulose-based carbon black@polyaniline electrodes. • Enhancement of the specific capacity and cycling stability by nanostructuring of PANI. • Green and cost-effective way to prepare high-performance pseudocapacitive electrode. Flexible, lightweight and electrically conductive composites based on renewable resources have recently attracted a growing interest for the development of high performance sustainable energy storage devices that can meet the needs of modern wearable and portable electronics. Herein, we developed a high performance carbon black@polyaniline (PANI) based flexible electrodes using a facile, low cost and environmentally friendly strategy. The strategy consisted of a co-deposition and nanostructuring of PANI layer with tailored morphology on the surface of carbon black and nanofibrillated cellulose (NFC) via in situ polymerization. NFC acted as a mechanical skeleton and imparted the electrode with strength and flexibility to ensure excellent electrochemical performance. The co-doping of PANI chains via a combination of a primary/secondary dopant, namely, HCl/poly(2-acrylamido-2-methyl-1-propanesulfonic acid), was used to control the morphology of PANI. Correlation between the textural properties of the carbon black, NFC loading, and the properties of the resulting electrodes was established. The maximum specific capacitance of 363±9 F/g at the potential scan rate of 50 mV/s was exhibited by the electrode with 60% of active material loading, for which an effective growth of hierarchical nanostructures of carbon black@PANI on the surface of NFC was achieved, leading to the highest specific surface area of the composite (861 m2/g) and a to a microporosity/mesoporosity balance. The remarkable cycling stability of the hybrid electrodes was attained as the specific capacitance retention was close to 100% with a negligible capacity decay within the tested period (over 500 cycles) regardless of the amount of the active material. This study provides an eco-friendly and cost-effective way to prepare high performance flexible electrodes for pseudo-capacitors [Display omitted] [ABSTRACT FROM AUTHOR]

Various luminophores produce strong electrogenerated chemiluminescence during cathodic pulse polarization of the present insulating film-covered carbon paste electrodes in fully aqueous solutions. First electrodes made of a commercial conductive carbon paste were successfully utilized as working electrodes and their surface was characterized by ESCA. Then custom in-laboratory made improved composite electrodes were manufactured from the same insulating polymer and conducting carbon black particles. The relationship between the amount of carbon present on the composite electrode, in the bulk and on the surface, and the intensity of electrogenerated chemiluminescence was studied further. The overall performance of these composite electrodes makes them viable low-cost replacements for metal/insulator type electrodes such as oxide-coated silicon electrodes. [ABSTRACT FROM AUTHOR]

The application of gas diffusion electrodes (GDE) modified with carbon black materials at high overpotentials leads to the substantial production of H 2 O 2 via oxygen reduction reaction. The greatest challenge in this process lies in the reduction of the high overpotentials without affecting H 2 O 2 selectivity. One way of circumventing this problem is through the modification of GDEs with coordination compounds. The present work investigates the modification of Printex L6 carbon (CPL6) with different amounts of porphyrin complexes containing the following metallic centers: Mn, Co, Ni, Cu and Zn. The application of 5.0 wt % Co-Porphyrin/CPL6 modifier yielded the best results, with high selectivity for H 2 O 2 generation (90.2%) and marked improvement in catalytic activity (72.6%) compared to CPL6; these positive effects are attributed to the enhancement of both the interaction energy between Co and HOO* reaction intermediate and the effect of the conjugated π-electrons of the CPL6. The application of the modified GDE led to the electrogeneration of 340 mg L−1 of H 2 O 2 with energy consumption of 86.6 kWh kg−1 and 92.1% improvement in efficiency compared to the unmodified GDE. Thus, the findings show that the 5.0 wt % Co-Porphyrin/CPL6 modifier is an excellent cathode for application in H 2 O 2 generation and in electrochemical advanced oxidation processes. [Display omitted] [ABSTRACT FROM AUTHOR]

• PFSA ionomer/N-doped CB is solely used as electrolyte in the PEFC cathode. • Carbon atoms adjacent to nitrogen derive a homogeneous distribution of the ionomer. • Cell performance is notably improved by superior activity and O 2 transportation. • This is attributed to suppression of catalyst poisoning and agglomeration of ionomer. • Cell durability is also enhanced due to higher graphitization of N-doped CB. An implementation of the polymer electrolyte fuel cell (PEFC) electrode, composed of the perfluorinated sulfonic acid (PFSA) ionomer with unprecedented uniform distribution, has recently gained a great attention due to its positive impact on the cell performance as well as durability. However, an issue with the conventional electrodes is a stronger adsorption of sulfonate terminal groups specifically onto Pt catalyst than carbon black (CB) support, that accelerates an inhomogeneous distribution of the PFSA ionomer. In this work, we report a novel PEFC electrode by introducing the ionomer immobilized onto nitrogen-doped carbon black (I/NCB) as electrode binder as well as electrolyte. The carbon atoms adjacent to nitrogen allow a considerable attraction with sulfonated groups over the NCB surfaces, which creates more homogeneous distribution of ionomer when compared with Pt/CB in the conventional electrode. As compared with the conventional electrode, the electrode employing I/NCB presents a superior activity towards oxygen reduction reaction (Pt mass activity increased from 91.3 to 139.6 A g−1) and mass-transport characteristics (mass-transport resistance decreased from 65.9 to 45.5 mΩ cm2), with the cell current density enhanced by 23% at 0.6 V. The enhanced cell durability is confirmed by less degradation in the electrochemically available surface area after the accelerated stress test of carbon support, mainly attributed to the promoted stability of NCB over CB. Given the advances in both performance and durability, the proposed electrode architecture based on I/NCB may provide an alternative pathway in obtaining better electrode kinetics and O 2 transport, along with an exceptional resistivity towards the carbon support degradation. [Display omitted] [ABSTRACT FROM AUTHOR]

A facile “one-step” route to produce a homogenous and highly stable cobalt phthalocyanine (CoPc)-based dispersion by using carbon black (CB) as supporting material is reported. Herein, CB is proposed as effective material to load CoPc in order to obtain a CB/CoPc hybrid nanocomposite dispersion suitable for modifying screen-printed electrodes (SPEs) by an easy and automatable drop casting approach. CoPc resulted anchored to CB by a non-covalent physisorption, confirmed by IR and UV-visible spectroscopies, allowing to preserve the electrochemical performances of CoPc. The resulting CB/CoPc-modified SPE was tested as sensing tool to detect thiocholine, an enzymatic product of butyrylcholinesterase (BChE). The use of CB/CoPc leads to a highly sensitive thiocholine detection by applying a low potential (+0.05 V vs. internal reference) without fouling problem, a typical drawback that affects the thiol electrochemical detection. The favorable characteristics of the sensor were exploited for an easy BChE biosensor fabrication that renders this biosensor well suitable for mass-production. This electrochemical monoenzymatic biosensor was then challenged towards paraoxon, chosen as model organophosphorous pesticide, obtaining a low detection limit (18 nM). The suitability of the biosensor was tested in a waste water sample obtaining satisfactory recovery values, thus demonstrating its capability in such complex matrix. [ABSTRACT FROM AUTHOR]

Thermoplastic carbon composite electrodes have been introduced by our group as novel electrodes with improved electrochemical properties and previously applied for accurate detection of biomarkers using voltammetric methods. Because of their exceptional properties, we hypothesized they would work well as potentiometric ion-selective electrodes as well. In this work, potassium selective thermoplastic electrodes (TPEs) were developed for potentiometric detection for the first time and applied in biofluids. TPEs were fabricated using mixture of polystyrene and polycaprolactone and two types of graphite (MG1599 and Nano19) for comparison, and modified with carbon black via drop-casting. Carbon black modification was optimized in the presence of various numbers of carbon black layers, while ion selective membrane components were optimized at different component ratios. Under optimized conditions, TPEs exhibited Nernstian response to K + with sensitivity of 59.3 ± 1.01 mV decade−1 and near-Nernstian response with sensitivity of 56.8 ± 1.7 mV decade−1 within a linear range of 1.0 × 10−4 M-1.0 × 10−1 M with a LOD of 1.0 × 10−4- M for Nano19- and MG1599-based TPEs, respectively. The K +-selective TPEs demonstrated rapid response (4 s) and excellent stability, repeatability and reproducibility. The applicability of electrodes were shown in human pooled urine and artificial interstitial fluid samples with potassium ion concentrations ranging from healthy and unhealthy levels. Therefore, the electrodes could be used in healthcare applications for accurate detection of K + exists in complex matrix and can be easily adapted to simultaneously monitor other ions for diagnosis of diseases due to miniaturization of TPEs. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel laccase-modified screen printed electrode (SPE) has been developed. [•] Bionanocomposite sensor is optimized in terms of enzyme loading, pH and applied potential. [•] Linear range, sensitivity and LOD are assessed for BPA determination. [•] The biosensor has been challenged in tomato juice samples. [ABSTRACT FROM AUTHOR]

The synergic combination of printed electronics and printed electrochemical sensors has recently emerged as a new route for developing smart chemical wearable devices applied to sweat monitoring. Sodium ion is one of electrolytes monitored in sweat to evaluate sweating level for electrolyte replacement recommendations. Herein, we report the development of new designed screen-printed electrodes, in which working electrode has been easily modified by drop-casting with the nanomaterial carbon black and a selective membrane cocktail, and the reference electrode with a polyvinyl butyral-based membrane. Once optimised all conditions, the screen-printed electrochemical sensor demonstrated no aqueous layer formation between working electrode and selective membrane, long-term potential stability, good shelf life, and resistance to interferences from oxygen and light. The carbon black-based sensor allowed for the detection of sodium ions in range 10-4 M e 1 M with a slope of 58 ± 3 mV/decade and a detection limit of 63 µM. The applicability for sweat analysis was evaluated by analysing three sweat samples collecting during running activity, obtaining concentrations of 44 ± 4 mM, 55 ± 6 mM, and 47 ± 3 mM, values in agreements with sodium ions content in healthy people, as well as using artificial sweat with recovery values of 90 ± 3%, 94 ± 2%, and 94 ± 5%. [ABSTRACT FROM AUTHOR]

Abstract: Li4Ti5O12/C (LTO/C) is synthesized by solid-state reaction with citric acid added as the conductive carbon source, and the residual carbon is only 0.47wt%. For comparison, bare LTO is prepared under similar conditions. The electrodes for both samples are prepared without commercial carbon black added. It shows that the LTO/C composite electrodes perform much better than that of LTO. Combined with XRD, XPS, SEM and TEM analysis, it is suggested that the particle size effect could be dismissed, and the main factors influencing the performances should be attributed to the Ti (III) existence and/or the in situ generated residual carbon, both of which are introduced by citric acid. The two main factors influencing the character can not be separated here, but they both improve the conductivity. So, it indicates that with proper strategies to enhance the electronic conductivity of the material, the electrode of spinel lithium titanium oxide with no carbon black added will exhibit better electrochemical behavior, though the metallic Li7Ti5O12 exists. [Copyright &y& Elsevier]

Abstract: Composites of layered structured Birnessite–MnO2 and tunnel structured Hollandite–MnO2 in presence of acetylene black were synthesized as positive electrode materials for rechargeable Mg-ion batteries. Reversible insertion/extraction of Mg-ion in the host structures was examined in the potential range of −1.8 to 1.0V vs. Ag/Ag+. Results indicated that Mg-ion exchanged Birnessite/acetylene black composite showed the highest discharge capacity (109mAhg−1) at 1st discharge, when compared to other microstructures of Birnessite. Meanwhile, the composite comprising of 65wt% Hol–MnO2 and 35wt% acetylene black showed very high insertion of Mg-ion (0.87Mg/Mn) corresponding to discharge capacity of 475mAhg−1 when tested at 60°C in galvanostatic mode. The layered and tunneled framework of the MnO2 was retained with minor displacive adjustments even after substantial Mg-ion insertion/extraction after several cycles. However, large specific capacity loss was observed after 20 cycles in all of the microstructures probably due to Mg-ion trapping in the host lattice. Furthermore, the effect of the cation (K+) present in the tunnel of Hollandite on Mg-ion diffusion was analyzed as well and it was concluded that tunnel cation could impede the movement of Mg-ion in host structure. [Copyright &y& Elsevier]

Abstract: In this work, we studied the cycling performance of initially inactive Li2MnO3 electrodes prepared from micron-sized particles, at 30°C and 60°C and possible structural transitions that this material can undergo due to de-lithiation. It was found that being activated at elevated temperatures, Li2MnO3 electrodes demonstrate a steady-state cycling behavior and reasonable capacity retention after aging at 60°C. The main gases evolved during polarization of the Li2MnO3 electrodes are O2 evolved from the structure and CO2 and CO that can be formed due the reaction of oxygen with carbon black. It was found that a transformation of the Li2MnO3 layered structure into a spinel-like phase occurred during the initial charging of the Li2MnO3 electrodes, which were characterized as possessing domains of both layered and spinel-like structures. The results of the structural studies of these electrodes obtained by the X-ray diffraction and transmission electron microscopy were found to be in agreement with their Raman spectroscopic responses. We suggest that the mechanism of the charge compensation during the extraction of lithium at 60°C involves both oxygen removal from the Li2MnO3 structure and the exchange between Li+ and protons formed during the anodic oxidation of ethylene carbonate or dimethyl carbonate solvents in LiPF6 solutions at high potentials (>4.5V). It is assumed that the proton-containing structure Li2−x H x−y MnO3−0.5y is retained in a discharged state of the electrode and may decompose above 500°C with the formation of Li2O and manganese oxides accompanied by the release of water and CO2. [Copyright &y& Elsevier]

Abstract: A sensor based on a screen-printed electrode (SPE) modified with a stable dispersion of commercially available carbon black (CB) N220 was optimised and challenged with several thiol-containing compounds. This probe showed a significantly enhanced electrochemical activity respect to a bare SPE when tested with thiocholine, cysteine, glutathione and cysteamine. When challenged in amperometric batch mode, the response was stable and showed a linear dependence up to 1×10−5 moll−1 for thiocholine and cysteine. The very high sensitivity towards these thiols (299mAmol−1 lcm−2 for thiocholine and 441mAmol−1 lcm−2 for cysteine) was then used as the basis for developing an analytical method for mercury ion detection since a non electroactive complex (thiol–Hg) is formed in the presence of the metal. By selecting an appropriate concentration of thiocholine, a concentration of mercury as low as 5×10−9 moll−1 (1ppb) was detected. Satisfactory recovery was obtained when the system was tested on drinking water samples. [Copyright &y& Elsevier]

Abstract: Silver nanoparticle-modified composite electrodes were prepared by electroless forming silver nanoparticles in carbon black dispersed electroless silver plating solution, and then incorporating the silver nanoparticle/carbon black mixture in a polystyrene matrix. The electrooxidation of glucose in 0.1M NaOH was studied by using cyclic voltammetry. The electrode has surface-confined nanoparicles showing effective catalytic behavior in the studies of glucose oxidation. It showed stepwise electrocatalytic oxidation behavior clearly without suppression by high background redox current caused by inner layer silver of disk-type silver electrodes. Initially the glucose was catalytically oxidized by AgO, and then the reaction glucose oxidation intermediates with Ag2O were followed stepwisely. Based on the cyclic voltammetric results, pulsed amperometric detection parameters for flow injection analysis were optimized for sensitive detection of glucose. [Copyright &y& Elsevier]

The assembly of powdered materials into freestanding electrodes can avoid the usage of metallic current collectors and thus reduce the weight and cost of devices. In this work, we prepared robust, binder-free freestanding membrane electrodes consisting of a three-dimensional network of bacterial cellulose (BC) with acetylene black and activated carbon uniformly embedded. Filtration as a facile method was employed to prepare the highly hydrophilic and conductive porous network. This architecture facilitated electrolyte infiltration and significantly enhanced the electrolyte uptake (6 times of the entire electrode weight), which subsequently improved ion transport and reduced the contact resistance between electrode and electrolyte. Owing to the high porosity, excellent wettability and the efficient utilization of active material, the obtained freestanding electrode with a mass loading of 3 mg cm−2 delivered a high capacity of 276 F g−1 at 1 A g−1. It also exhibited an excellent cycle stability at 5 A g−1 without detectable capacity fading after 10,000 cycles in a two-electrode system. More importantly, a high specific capacitance of 167 F g−1 at 1 A g−1 and a high energy density of 5.3 W h kg−1 at 163 W kg−1 with respect to the overall weight of electrode were achieved at a commercial level mass loading of 10 mg cm−2, which considerably outperformed common electrode using nickel foam as current collector. This work provided a facile and effective way in producing lightweight, low cost and high-performance electrodes. [ABSTRACT FROM AUTHOR]

3D-printing of conductive carbon materials in sensing applications and energy storage devices has significant potential, however high resistivity of 3D-printed filaments poses a challenge. Strategies to enhance sensors post printing are time consuming and can reduce structural integrity. In this work, we investigated the effects different printing layer thickness and orientation can have on the electron transfer kinetics and resistivity of conductive materials. The response of these electrodes was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and imaging. Electrodes printed with the lowest layer thickness of 0.1 mm in a vertical orientation had the greatest conductivity. With increasing print layer thickness and printing in a horizontal orientation, the electrode was more resistive. This work is the first to demonstrate the significant impact 3D-printing parameters can have on the electron transfer kinetics of carbon conductive electrodes. The implications of this study are important in defining the manufacturing process of electrodes for all applications. Electron transfer in 3D-printed electrodes: 3d-printed electrodes are printed in vertical and horizontal orientation with thickness ranging from 0.1 to 0.4 mm. Electron transfer kinetics are enhanced in vertical orientation at lower print layer thickness due to the formation of less air voids and more conductive pathways. Image 1 [ABSTRACT FROM AUTHOR]

Solid-electrolyte interface (SEI) between the active material and the electrolyte is critically important to the electrochemical performance of a lithium-ion battery. In this work, a depth profile measurement of the SEI layer after prolonged electrochemical cycling is reported in order to quantify the influence of conducting additives in the development of this layer in mesocarbon microbeads (MCMB) electrodes. It is shown that the SEI in the electrodes having multiwalled carbon nanotubes (CNT) as conductive additive is primarily a multi-layered structure consisting of an outer organic layer near the electrolyte/SEI interface and an inner inorganic layer near the SEI/electrode interface. The chemical analysis of such electrodes exhibits that the inorganic layer is made up of compounds such as Li 2 O, LiF and Li 2 CO 3, while the outer layer consists mainly of organic carbonates, oligomers, traces of randomly distributed Li x PO y F z and undissociated LiPF 6. The chemical analysis of electrodes with carbon black (CB) as conducting additive reveals a similar composition of the outer layer, whereas the inner layer shows a relatively uniform molar amount of organic and inorganic carbonates and species like Li x PO y F z and Li x PO y , resulting in a porous SEI layer which as confirmed in AFM and SEM characterizations. On the other hand, the electrodes containing hybrid (CB-CNT) conducting additives show a relatively higher oligomer content than the electrodes with CNT only. The SEI formed on electrodes with CB-CNT as additives is shown to offer increased flexibility to accommodate partial strain generated due to volume change with narrow cracks exhibited in the SEM micrographs. Further, the variation in surface features and roughness augment the XPS findings. [ABSTRACT FROM AUTHOR]

This work shows that the electrochemical activity of a 3D-printed electrode fabricated using a conductive composite of polylactic acid (PLA) containing carbon black (CB) can be substantially improved through a simple and fast chemical/electrochemical pretreatment in 0.5 mol L−1 NaOH. Scanning electron microscopy and infrared spectroscopy data showed that the pretreatment process promotes the removal of the non-conductive PLA material, providing greater exposure of the conductive particles. Cyclic voltammetry of the redox probe ferricyanide/ferrocyanide indicated faster electron transfer on the treated 3D-printed surface and increase in electroactive area. Moreover, electrochemical impedance spectroscopic results also confirmed faster electron transfer after surface pretreatment. As a proof-of-concept, a low-cost and sensitive method for the determination of cadmium and lead in real urine and saliva samples by square-wave anodic stripping voltammetry was developed. The chemical/electrochemical treatment provided an impressive 30-fold current increase in the detection of both metals. Acceptable limits of detection (2.9 μg L−1 for Cd2+ and 2.6 μg L−1 for Pb2+), wide linear ranges for both metals (30 μg L−1 to 270 μg L−1; R = 0.997), high stability (RSD lower than 4.5%; n = 10), and adequate recovery values (between 93% and 112%) for the analysis of spiked samples were achieved. Additionally, interday (n = 3), intra-day (n = 3), inter-electrode (n = 2) and inter-treatment (n = 2) experiments revealed RSD values lower than 6.5%, which indicates high reproducibility of the proposed treated 3D-printed electrode. The strategy here proposed opens up new applications for 3D-printed electrode in analytical electrochemistry with improved electrochemical sensing properties in comparison to screen-printed electrodes. [ABSTRACT FROM AUTHOR]

A 3D macroporous stainless steel fiber felt (SSFF) is used as base material and a simple water bath method is adopted to directly load Pd nanocatalysts on SSFF to fabricate the air cathode of microbial fuel cells (MFCs). The optimum Pd loading is explored on the basis of the optimized PVP additive amount and reaction temperature. To attain a high ORR activity, a conductive carbon black filling layer is added into the 3D pores of Pd-SSFF. A series of physical and electrochemical tests are conducted to characterize the morphology, chemical composition and oxygen reduction activity and then the obtained cathodes are installed in MFCs for electricity production verification. The results show that the Pd-SSFF cathode at a Pd loading of 0.5 mg cm−2 (Pd-SSFF-0.5) achieves high output voltage and power density (492.65 mV, 390.79 mW m−2) which are comparable to the conventional Pt/C electrode (504.80 mV, 405.47 mW m−2). Furthermore, with Pd-SSFF-0.5 cathode the high-voltage platform duration of MFC in one operation cycle is 2.79 times of that of Pt/C electrode. Excellent mechanical properties (high pressure and corrosion tolerance), high electric energy output and simple fabrication prove it is an efficient strategy to improve the overall performance of MFCs using the obtained cathodes. • 3D macroporous SSFF is proposed as base material in air cathode. • Pd nanocatalysts is loaded directly on SSFF with the simple water bath method. • This loading method can replace the complex preparation process of powder catalysts. • Filling carbon black into the 3D pores of Pd-SSFF helps improving ORR performance. • Excellent mechanical properties and high electric output are achieved by Pd-SSFF cathodes. [ABSTRACT FROM AUTHOR]

Salinity gradient (SG) energy is a large, renewable, and clean energy source, which naturally exists between river water and seawater and can also be created by engineering processes. Here, bismuth oxychloride (BiOCl) electrodes was used for efficient SG energy recovery in a chloride-ion concentration flow cell (Cl-CFC) based on a new mechanism, that is, chloride ion (Cl−) intercalation/deintercalation. Compared to previous Cl-CFC with BiCl 3 electrodes based on Cl− extraction/insertion (3.17 W m−2), the peak power density of the cell with BiOCl electrodes (4.36 W m−2) was higher under the same testing conditions when using synthetic river water (1 g L−1 NaCl) and seawater (30 g L−1 NaCl). Further investigations demonstrated that the relatively higher power density was attribute to the faster kinetics of Cl− intercalation/deintercalation at BiOCl electrodes than that of Cl− extraction/insertion at BiCl 3 electrodes. In addition, three BiOCl electrodes with different carbon black ratios (CB, 10%, 20% and 30%) were also prepared and examined in this study. Compared to BiOCl/10%CB and BiOCl/30%CB electrodes, the lower charge transfer and ion diffusion resistances, larger ion storage capacities and higher cell open circuit voltages of the BiOCl/20%CB electrodes were all beneficial to its higher power output. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H 2 O 2) is a green oxidant that widely used in environmental remediation and chemical industries, hence the exploration of suitable modified cathode for the cost-effective electrochemical synthesis of H 2 O 2 is of great importance. In this work, tert-butyl-anthraquinone (TBAQ) was attempted to modify four kinds of typical carbon materials (carbon aerogel, carbon nanotube (CNT), carbon black and graphene-doped carbon black) to fabricate gas diffusion electrode (GDE) to improve H 2 O 2 production for potential use in electro-Fenton process. It was found that CNT-GDE containing 2% TBAQ had the highest H 2 O 2 production (150.6 mg/L) with a high current efficiency (95%) and low energy consumption (2.43 kWh/(kg H 2 O 2)) among four carbon materials because of the redox of TBAQ and more active sites (C–C sp3 carbon and oxygen-containing functional groups). The effects of TBAQ addition amount, current and initial pH on H 2 O 2 performance were investigated. The presence of TBAQ could improve oxygen reduction activity, H 2 O 2 selectivity and hydrophobicity to improve H 2 O 2 production. Suitable current (50 mA) and initial pH benefited the enhancement in H 2 O 2 production. The CNT-GDE containing 2% TBAQ showed better H 2 O 2 production performance with good stability when comparing with literature, indicating promising for electro-Fenton application. • TBAQ was doped on four carbon materials cathode to improve electro-synthetic H 2 O 2. • 2% TBAQ on carbon nanotube (CNT) had the best H 2 O 2 performance among four cathodes. • Doping TBAQ can improve H 2 O 2 selectivity and hydrophobicity to improve performance. • Effect of current and initial pH on H 2 O 2 performance was investigated. [ABSTRACT FROM AUTHOR]