Stainless Steel Mesh Electrodes Research Articles

Design and Preparation at Scale of Ternary NiFe-M-Ox (M=Co, Mo) Catalysts for OER in Alkaline Media

Due to scarcity of Platinum Group Metals (PGMs) widely used in low temperature water electrolysis as cathodes (Hydrogen Evolution Reaction; HER) and anodes (Oxygen Evolution Reaction; OER) a boosting interest to their substitution to Earth abundant elements is observed. It was successfully demonstrated that elements like iron, nickel, cobalt and other (in their oxide and hydroxide forms) can be effective OER catalysts when operate at high pH ranges from 12 to 14 [1-3].This work is devoted to systematic investigation of influence of third element addition to NiFeOx system on a performance and stability of catalysts in alkaline OER. As a co-catalytic elements Mo and Co were selected, based on our previous experience [4,5]. A systematic study on an effect of NiFe-to-M ratio, concentration of precipitation agent and post-treatment temperature were evaluated in a wide range of parameters. Taking into account that mass loading of PGM-free OER catalysts is substantially higher than iridium/ruthenium once and can be up to several milligrams per cm2 all experiments were designed to be scalable. In a laboratory scale reactor, a fascinating batch size of 25g was achieved, using minimal amount of water-based solvents in order to minimize a waste stream generated. Presentation will discuss characterization of obtained materials by SEM, TEM, XPS, XRD and other methods as well as their performance, stability and durability in alkaline conditions, studying Oxygen Evolution Reaction. Acknowledgements and Statements. The authors acknowledge financial support from H2NEW and ElectroCat consortia. References. [1] X. Lyu, J. Li, J. Yang, A. Serov "Significance of Slight Ambient Temperature Variation on the Electrocatalyst Performance toward Oxygen Evolution Reaction" Journal of Environmental Chemical Engineering (2023).[2] X. lyu, A. Serov “Cutting-edge methods for amplifying the oxygen evolution reaction during seawater electrolysis: a brief synopsis” Ind. Chem. Mater., (2023).[3] X. Lyu, Y. Bai, J. Li, R. Tao, J. Yang, A. Serov "Investigation of oxygen evolution reaction with 316 and 304 stainless-steel mesh electrodes in natural seawater electrolysis" J. of Environmental Chemical Engineering 11 (2023) 109667.[4] A. Serov,N. I. Andersen, A. J. Roy, I. Matanovic, K. Artyushkova, P. Atanassov “CuCo2O4 ORR/OER Bi-Functional Catalyst: Influence of Synthetic Approach on Performance”, J. of The Electrochem. Soc. 162 (4) (2015) F449-F454.[5] N. I. Andersen, A. Serov, P. Atanassov “Metal Oxides/CNT Nano-Composite Catalysts for Oxygen Reduction/Oxygen Evolution in Alkaline Media”, Appl. Catal. B: Environmental 163 (2015) 623-627.

Stainless steel as gas evolving electrodes in water electrolysis: Boosting the electrocatalytic hydrogen evolution reaction on electrodeposited Ni@CoP modified stainless steel electrodes

High efficient and durable electrocatalytic electrodes play a vital role in energy conversion and storage. In this concern, water electrolysis technology needs high performance electrodes with high activity and stability to implement this technology for green hydrogen production. Here, this study reports on the development of self-supported electrodes for the hydrogen evolution reaction (HER) based on sequential electrodeposition technique. First, the CoP has been deposited on stainless steel mesh (SSM) electrode followed by deposition of Ni to form Ni@CoP electrocatalysts standing on SSM. The loading amount of Ni was studied to achieve a high catalytic activity. The developed electrodes have been investigated with FE-SEM, EDX, XRD and XPS to identify their morphological properties as well as their chemical states and compositions. Electrocatalytic activity and durability have been studied in alkaline media by different electrochemical methods, such as LSV, EIS and CP. The results showed that the optimum deposition time of 10 min (10Ni@CoP) exhibited the higher catalytic activity in term of overpotential and Tafel slope giving a overpotential of 188 mV at 10 mA cm−2 with a small Tafel slope of 69 mV.dec−1 compared to CoP electrode with overpotential 266 mV and Tafel slope of 105 mV.dec−1 highlighting the role of Ni in enhancing the catalytic activity of the developed electrodes towards HER. Moreover, the Ni@CoP showed high stability under continues electrolysis at 50 and 100 mA.cm−2. These findings have been discussed in light of porous structure of the electrodes and introducing of Ni particles which led to creating more active sites and enhancing the hydrogen adsorption/desorption and thus facilitating the HER kinetics. The facial preparation method of self-supported electrodes and the obtained activity and stability of Ni@CoP electrodes render them as potent electrodes for HER in alkaline water electrolysis.

The Effect of Illumination, Electrode Distance, and Illumination Periods on the Performance of Phototrophic Sediment Microbial Fuel Cells (PSMFCs)

Microbial fuel cells (MFCs) can potentially be used to overcome issues with battery powered light buoys and their frequent maintenance. In this study, a phototrophic sediment microbial fuel cell (PSMFC) was chosen, as the microalgae provide oxygen to be reduced on the cathode and to release the necessary nutrients for the bacteria on the anode. To achieve this, we studied the effect of illumination, the period of the illumination, and the distance between 9-cm2 stainless steel mesh electrodes on the performance of the MFC. The illuminated cells were able to produce higher OCP (max. 205.2 mV) and higher power density (max. 0.68 mW/m2). However, the highest current was achieved during the unilluminated variation (max. 5.3 μA unilluminated and 3.3 μA illuminated). Prolonged illumination produced a higher OCP, current, and power density. A longer electrode distance produced a higher OCP, power density, and current. SEM analysis showed that biofilm formation tended to be scattered at lower electrode distance and more clumped (filling the anode area) at higher electrode distance. Through FTIR analysis, it was found that all MFC variations had the same organic matter, but a more concentrated organic content was found in the MFC at longer electrode distances.

Metal-organic framework-derived Se-blended ZrO2 with a nitrogen-doped carbon heterostructure for electrocatalytic overall water splitting.

Designing low cost, highly active and efficient non-noble metal bifunctional electrocatalysts with remarkable operational reliability for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is indispensable for large-scale water electrolysis and the development of clean energy conversion technologies. Herein, we decorated a two-dimensional (2D) selenium-blended zirconium dioxide (Se-ZrO2) on the surface of a nitrogen-doped carbon heterostructure (Se-ZrO2@NC), which was derived from Zr-metal-organic frameworks (Zr-MOFs), and loaded it on a stainless-steel mesh electrode. Accordingly, phenomenal electrocatalytic performance was observed for the Se-ZrO2@NC-loaded electrode with a minimum overpotential of 48 mV for the HER and 251 mV for the OER at 10 mA cm-2 current density in acidic and alkaline mediums, respectively. Moreover, a complete cell set up was constructed, where the OER and HER were studied at the anode and cathode, respectively, with a cell potential of 1.58 V to reach a current density of 10 mA cm-2 together with an exciting long-term stability of over 48 h. The developed Se-blended 2D transition metal dioxides on the 2D nitrogen-doped carbon heterostructure extended to a variety of catalytically active materials that would provide highly active and stable electrocatalysts for alkaline water splitting studies.

Enhancing microbial fuel cell performance with carbon powder electrode modifications for low-power sensors modules

Microbial Fuel Cell (MFC) is a promising technology for harnessing energy from organic compounds. However, the low power generation of MFCs remains a significant challenge that hinders their commercial viability. In this study, we reported three distinct modifications to the stainless-steel mesh (SSM), carbon cloth, and carbon felt electrodes using carbon powder (CP), a mixture of CP and ferrum, and a blend of CP with sodium citrate and ethanol. The MFC equipped with an SSM and CP anode showed a notable power density of 1046.89 mW.m-2. In comparison, the bare SSM anode achieved a maximum power density of 145.8 mW m-2. Remarkably, the 3D-modified SSM with a CP anode (3D-SSM-CP) MFC exhibited a substantial breakthrough, attaining a maximum power density of 1417.07 mW m-2. This achievement signifies a significant advancement over the performance of the unaltered SSM anode, underscoring the effectiveness of our modification approach. Subsequently, the 3D-SSM-CP electrode was integrated into single-chamber MFCs, which were used to power a LoRaWAN IoT device through a power management system. The modification methods improved the MFC performance while involving low-cost and easy fabricating techniques. The results of this study are expected to contribute to improving MFC's performance, bringing them closer to becoming a practical source of renewable energy.

Effect of the Magnetostriction Induced on the Crystalline Structure of Nanoparticulate TiO2 Films Supported on Stainless Steel Mesh Electrodes and Their Relationship with the Photocatalytic Decoloration of Aqueous Orange G Solutions

The study of ferromagnetism (FM) in non-cubic semiconductor oxides such as defective TiO2 is attractive due to their applications in photocatalysis [1]. FM can be activated in TiO2 nanomaterials by promoting oxygen vacancies (VO) located in paramagnetic defected sites Ti3+VOTi4+. In this context, the VO can induce in Ti3+-doped TiO2 structures remarkable magnetic anisotropy energy (MAE) of 6.51x106 erg/cm3, thus indicating the magnetic saturation should be achieved at magnetic fields (MFs) of ~425 gauss [2,3]. Therefore, magnetostriction can be observed in ferromagnetic TiO2 films as a phenomenon in which their dimensions and shapes are changed when they are magnetized. In this work, stainless steel mesh electrodes (ss) were modified by nanoparticulate TiO2 films (ssTiO2) enriched by Ti3+VOTi4+ sites, to gain an understanding of the effects of magnetostriction on the photocatalytic properties of ferromagnetic TiO2 electrodes. In this way, MFs having intensities (H) of 125, 250, 500, 1000, and 2000 gauss were applied to the ssTiO2 electrodes for 80 min under UV light illumination for increasing the number of Ti3+VOTi4+ sites. Our results revealed that the magnetic lines promoted compression of the TiO2 structure when achieving pressures p>4.67 GPa for H>425 gauss in p=1/2(MAE/4p gauss2)H 2. Consequently, the degree of disorder (0<b<1) of the electron traps at the intra-bandgap state's distribution along the thickness-axis(i.e. the x-axis) of TiO2 films decreased significantly because the fraction of trapped electrons f trap(x) at the quasi-Fermi level EF(x) was maximized according to f trap(x)=m[em (E F (x)-E F (0))-1], where m=kT/b (k and T are the Boltzmann constant and the absolute temperature) [4,5]. Later, it was observed a significant increase of trapped holes able to carry out the direct photocatalytic oxidation of aqueous orange G (without electron scavenger’s assistance, e.g. gaseous O2). On the other hand, the photogeneration of oxidant •OH radicals decreased dramatically while H increased [6].[1] Y. Bian et al., RCS Adv., 11(2021)6284.; [2] D. Kim et al., J. Phys.: Condens. Matter,21(2009)195405.; [3] B. Shao et al., J. Appl. Phys.,115(2014)17A915. [4] N. Kopidakis et al., J. Phys. Chem. B, 107(2003)11307. [5] J. van de Lagemaat et al., J. Phys. Chem. B,104(2000)4292. [6] K.-I Ishibashi et al., J.Photochem.Photobiol.A,134(2000)139-142. Acknowledgements The authors thank the National Council for Science and Technology (CONACyT) Mexico for the funding support (grants CB No. 258789 and FOINS No. 3838). JIVN thanks CONACyT for his doctoral fellowship support (grant No. 893260).

Imaging of CO2 and Dissolved Inorganic Carbon via Electrochemical Acidification-Optode Tandem.

Dissolved inorganic carbon (DIC) is a key component of the global carbon cycle and plays a critical role in ocean acidification and proliferation of phototrophs. Its quantification at a high spatial resolution is essential for understanding various biogeochemical processes. We present an analytical method for 2D chemical imaging of DIC by combining a conventional CO2 optode with localized electrochemical acidification from a polyaniline (PANI)-coated stainless-steel mesh electrode. Initially, the optode response is governed by local concentrations of free CO2 in the sample, corresponding to the established carbonate equilibrium at the (unmodified) sample pH. Upon applying a mild potential-based polarization to the PANI mesh, protons are released into the sample, shifting the carbonate equilibrium toward CO2 conversion (>99%), which corresponds to the sample DIC. It is herein demonstrated that the CO2 optode-PANI tandem enables the mapping of free CO2 (before PANI activation) and DIC (after PANI activation) in complex samples, providing high 2D spatial resolution (approx. 400 μm). The significance of this method was proven by inspecting the carbonate chemistry of complex environmental systems, including the freshwater plant Vallisneria spiralis and lime-amended waterlogged soil. This work is expected to pave the way for new analytical strategies that combine chemical imaging with electrochemical actuators, aiming to enhance classical sensing approaches via in situ (and reagentless) sample treatment. Such tools may provide a better understanding of environmentally relevant pH-dependent analytes related to the carbon, nitrogen, and sulfur cycles.

Unraveling the Enhanced Electrochemical Performances of Nickel Aluminum Sulfide Lattices for Overall Water Splitting and as Counter Electrode Materials for Dye-Sensitized Solar Cells

The development of a high-performance precious metal-free multifunctional electrocatalyst for overall water splitting is a promising sign for future energy research. Here, a new strategy has been followed for the synthesis of novel-structured binary metal chalcogenide electrocatalysts, such as nickel aluminum sulfide (NiAl2S4) or nickel aluminum selenide (NiAl2Se4) spinels. The new chalcogenides, NiAl2S4 or NiAl2Se4, were confirmed by different physicochemical characterizations. Using a 316 stainless steel (SSL) mesh electrode as a three-dimensional conducting substrate, the electrocatalytic overall water splitting reaction was studied. Here, NiAl2S4 spinel outperformed the other metal chalcogenide in terms of electrocatalytic activity and charge transport in the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER), and overall water splitting in alkaline medium. Moreover, NiAl2S4 spinel provided the finest electrocatalytic efficiencies compared to other benchmark electrocatalysts with minimized overpotentials, such as 47 or 290 mV for HER or OER, respectively, to reach the current density of 20 mA cm–2. In overall water splitting studies, a two-electrode system was formulated to show a very low potential of 1.54 V at a current density of 20 mA cm–2. Further, the prepared NiAl2S4 electrocatalyst-loaded 316 SSL electrode demonstrated excellent durability in HER, OER, and overall water splitting reactions. The obtained Faradaic efficiency was 97%, which is due to the two-dimensional sheet-like morphology of NiAl2S4, enabling a high active surface area for efficient water electrolysis. Furthermore, NiAl2S4 spinel performed well as a counter electrode (CE) material in dye-sensitized solar cells, with an efficiency of 5.02% compared to Pt (5.38%) on the fluorine-doped indium tin oxide electrode.

Three-dimensional macroporous structure and surface carbon-coating modification of stainless-steel anode boost bioelectrocatalytic performance

Bioelectrochemical systems (BESs) is a promising and sustainable technology for wastewater treatment, and the practical application of BESs generally requires scalable three-dimensional (3D) electrodes. In this study, we present a stainless-steel crochet mesh electrode (P-SS) with 3D macroporous structure, and modified by carbon coating through pyrolyzing residual lubricating oil in the mesh production process. The effect of 3D macroporous structure and surface carbon-coating modification on the improvement of electrode bioelectrocatalytic performance was investigated during the study. When the electrode was used as the anode in BESs reactors, a superior bioeletrocatalytic current was generated, reaching a maximum projected current density of 9.95 mA·cm−2 and achieving a highest geometric current density of 1.89 mA·cm−2 ever recorded. We found the 3D macroporous structure and surface carbon-coating modification enabled the electrode well mass transfer, excellent biocompatibility and fluent electron transport, finally boosted the superior bioeletrocatalytic performance. We also verified the electrode has a remarkable stackability as suggested by the bioelectrocatalytic current increasing linearly with the increase of electrode thickness. In addition, the acceptable capital cost (＜6500 $·m−3), adequate mechanical strength and feasible industrial process of this novel electrode all indicate its great prospects for the scaling-up of BESs.

Electrolysing mud: Membraneless electrolysis of water for hydrogen production using montmorillonite-rich marine mud

This paper describes a design for a low-cost membraneless water electrolyser for the production of green hydrogen that used a viscous electrolyte of naturally abundant montmorillonite-rich marine mud in a DEFT (divergent electrode flow through) geometry with stainless steel (304) mesh electrodes. The ratio of smectite to non-swelling clays in the mud was 1:2. The electrolyte was prepared by resuspending the mud in tap-water to remove the salt, and NaOH 1 M added to enhance the ionic conductivity, as measured by both Electrochemical Impedance Spectroscopy (EIS) and by the slope of DC current/voltage curves. Successful separation and collection of the hydrogen and oxygen gas was inferred from the ratio of 2:1 in the volumes of hydrogen and oxygen collected. Both acid and alkali treatments were trialled and it was found that, whereas acid treatment flocculated the mud, adding NaOH increased the dispersion, conductivity and viscosity, and reduced clogging. The conductivity of both the 24% dry mass alkali mud and a control 4% dry mass alkali bentonite suspension increased to that of pure NaOH 1 M when repeatedly electrolysed. Hydrogen and oxygen gas was collected for 10% and 24% dry mass muds. The less viscous 10% dry mass mud showed turbulent liquid-like behaviour which led to gas mixing but the 24% mud showed stable, solid-like flow and reliable gas separation. Three components of the energy efficiency of the electrolysis process are reported and discussed – the voltage efficiency of 42%, a gas collection efficiency of 50% and the auxiliary power efficiency of 60%. The overall energy efficiency due to these three contributing efficiencies, was 13% of the Higher Heating Value of 142 MJ/kg H2 for a current density of 45 mA/cm2. This mud electrolyser may still be considered worth developing for an off-grid, low budget site with a low-power source of renewable energy.

Investigation of oxygen evolution reaction with 316 and 304 stainless-steel mesh electrodes in natural seawater electrolysis

Two commercially available stainless steel mesh substrates (316 SS and 304 SS) were evaluated as electrodes for oxygen evolution reaction (OER) in natural seawater electrolysis. The results show the 304 SS is less stable against corrosion under neutral (pH of 8.5) and low alkaline (0.1 M NaOH, pH of 12.8) seawater electrolytes because of the direct metal dissolution and chlorine evolution reaction (CER), and the 316 SS is superior to 304 SS in terms of electrocatalytic activity and resistance to corrosion under the same media. The performance of 304 SS is comparable to 316 SS under the high alkaline (1 M NaOH, pH of 13.7) seawater electrolyte, where the CER and metal dissolution are suppressed by OER. The overpotential for 304 and 316 SS is around 430 mV at 10 mA cm−2, and the Tafel slopes are below 50 mV dec−1 under the high alkaline (1 M NaOH) seawater electrolyte, showing promising performance. The poor resistance to corrosion of 304 SS is attributed to the low Mo content, and it is supposed that the stability of both 304 and 316 SS can be improved further with the addition of Mo content. This work expands on promising substrates for natural seawater electrolysis, with cost and performance advantages.

Convenient construction of porous dendritic Cu-doped Ni@PPy/stainless steel mesh electrode for oxidation of methanol and urea

In multifunctional catalysts, Ni-based alloys and compounds can be used for methanol oxidation reaction (MOR) and urea oxidation reaction (UOR). Herein, the porous dendritic NiCu@PPy/316L stainless steel mesh (SSM) electrode is prepared by dynamic hydrogen bubble template electrodeposition, followed by cyclic voltammetry electrodeposition of polypyrrole (PPy) conductive polymer on the electrode surface. Among them, dynamic hydrogen bubbles successfully assisted the formation of porous structures in the Ni-based deposition layer. In addition, the morphology of the resulting Ni-based layer further evolves from particle stacking to dendritic with high specific surface area with Cu doping. Eventually, 2-NiCu/SSM achieves current densities of 294.5 mA·cm−2 (MOR) and 278.6 mA·cm−2 (UOR) at 0.8 V, respectively. The PPy coating prevents the agglomeration of NiCu particles in the catalytic layer and further improves the persistence of the electrochemical performance. After 2000 cycles, the current densities of 2-NiCu @PPy/SSM in the new electrolyte are maintained at 89.1% (MOR) and 94.8% (UOR) of the original value, with a 10% increase for MOR and a 7% increase for UOR compared to the sample without PPy coating (2-NiCu /SSM).

Electrocatalyst for oxygen evolution reaction and methanol oxidation using surface-oriented stable NiSnO3 nanospheres anchored g-C3N4 nanosheets

Transition metal oxides have arisen as smart and inexpensive electrocatalytic materials for water oxidation. In this work, a simple hydrothermal method is demonstrated for the first time to synthesize perovskite-type NiSnO3 nanospheres interacted with graphitic carbon nitride (g-C3N4) nanosheets with fruit-beared cherry tree like morphology and investigate its surface-oriented electrocatalytic performance such as oxygen evolution reaction (OER) and methanol oxidation reaction (MOR). First, the structural and morphological analysis of the as-synthesized nanohybrid has been studied using various physico-chemical techniques to confirm the bonding interaction between NiSnO3 nanospheres and g-C3N4. For comparison, NiO, SnO2, and NiO/SnO2 nanocomposites were also synthesized and studied. This study highlights the surface-derived synergistic interaction between g-C3N4 nanosheets and NiSnO3 nanospheres, which have absolutely led the prepared NiSnO3/g-C3N4 nanohybrid loaded on 316 stainless steel (SSL) mesh electrodes to excellent electrocatalytic performances, assessed using linear sweep voltammetry (LSV), cyclic voltammetry (CV), and impedance analysis. The nanohybrid loaded electrode needs a low overpotential of 240 mV to reach the current density of 10 mA cm−2 and a Tafel slope of 42 mV dec-1 for OER. In addition, the synthesized nanohybrid loaded electrode was tested for methanol oxidation, which shows an enhanced electrocatalytic performance with a current density of 295 mA cm−2. The produced nanohybrid electrode also demonstrates long-term stability for both OER and MOR, suggesting as an alternate to noble metal electrocatalyst.

Nano MnOx encapsulated pyrrole-carbazole copolymer and polyvinyl chloride/carbon-coated flexible electrodes for solid-state supercapacitor cell

Pyrrole (Py) and carbazole (Cz) monomers are polymerized simultaneously in the presence of MnOx nanoparticles synthesized chemically on a stainless steel mesh (SSM) electrode by the pulse galvanostatic method in an acetonitrile medium. The resulting p(Py-co-Cz)/MnOx composite is characterized by cyclic voltammetry EIS, GCD XPS, XRD, FESEM, BET, and TEM. Since the current is applied for short periods in the presence of both monomers, p(Py-co-Cz) copolymer chains occur in short lengths, suitable for supercapacitor electrodes. The copolymer has higher Cm and lower Rct values as well as higher porosity that improves ion transport, thus greater stability than the homopolymers. It may be due to tricyclic Cz segments located between Py segments in the chains, which inhibit degradation. During the synthesis, nano-sized MnOx is also encapsulated homogeneously into the p(Py-co-Cz) coating, where 5 % is the weight percentage of manganese. Since the composite combines the advantages of the conductive polymer and metal oxide, it has the lowest Rct and highest Cm values among the coatings here. The p(Py-co-Cz)/MnOx coating with 10 mg cm−2 exhibits a high specific capacitance of 352 F g−1 at 5 A g−1 as well as flexibility, as its specific capacitance remains nearly stable (99 %) up to a bending angle of 90°. The cathode prepared from polyvinyl chloride (PVC)/activated carbon/carbon black on SSM operates within a wide voltage range of 0 to −1.5 V at 98 % cycle stability after 1000 cycles. The asymmetric cell configuration with the flexible anode and cathode electrodes provides 38 kW kg−1 and 5.28 Wh kg−1 at 5 A g−1 at a wide potential range of 2.1 V in PVA/Na2SO4 gel electrolyte, and the cycling stability was 67 % after 1000 cycles.

Electrode Layout Optimization and Numerical Simulation of Cast Conductive Asphalt Concrete Steel Bridge Deck Pavement.

In order to obtain the optimal electrode layout and ice melting effect of cast conductive asphalt concrete steel bridge deck pavement, firstly, pouring conductive asphalt concrete was prepared; secondly, different electrode materials and layout methods were selected to test the heating rate of the specimen from start to 120 min, and the electrode materials and layout methods were optimized. Then, the finite element analysis software ANSYS was used to build the model for heating and ice melting simulation, and the indoor test was used to further verify the ice melting effect of the cast conductive asphalt coagulation with or without the insulation layer. Finally, the thermal-structural coupling analysis of cast conductive asphalt concrete steel bridge deck pavement was carried out using ANSYS finite element software. The results showed that the stainless steel electrode material had the best heating effect, and the electrode thickness in the range of 0.1~3mm had no effect on the heating effect. The intermediate heating rate of the upper surface of the stainless steel sheet electrode cast conductive asphalt concrete in the left and right external electrodes was 8 °C/h, while the intermediate heating rate of the upper surface of the stainless steel mesh electrode cast conductive asphalt concrete was 12.9 °C/h. The layout of the left and right buried stainless steel metal mesh was able to effectively improve the snow melting efficiency; ANSYS finite element ice melting simulation was used to obtain the variation law of ice melting efficiency and a temperature field of cast conductive asphalt concrete. The indoor ice melting test showed that when melting the same thickness ice layer at 50 V voltage, it took 240 min with an insulation layer and 720 min without an insulation layer, which was three times that of the ice with an insulation layer, which further verifies the superiority of its ice melting effect. The most unfavorable load position of pavement under load and temperature field was determined. The maximum tensile stress and compressive stress of the pavement surface were transverse, and the maximum shear stress of the pavement bottom was transverse.

Investigation of oxygen evolution reaction with Ni foam and stainless-steel mesh electrodes in alkaline seawater electrolysis

Alkaline seawater electrolysis is a promising method for hydrogen production; however, little progress has been made in investigating the substrates for oxygen evolution reaction (OER) electrocatalysts. Ni foam and stainless-steel mesh (SS mesh) were investigated systematically for OER in alkaline seawater electrolysis in this work. The overpotentials and Tafel slopes with SS meshes are smaller than Ni foams, and it also exhibits excellent stability. Interestingly, the performance of the SS mesh even outperforms various non-noble metal electrocatalysts and is comparable to commercial RuO2 and IrO2. The corrosion conditions of Ni foam and SS mesh electrodes were studied and revealed. Furthermore, the electrochemically active surface area (ECSA) of Ni foam is 12 times higher than SS mesh in the same geometric area, indicating the electrochemical activity of SS mesh is much superior to Ni foam. This work expands on promising substrates for alkaline seawater electrolysis, with cost and performance advantages.

Mesoporous sulfur-modified metal oxide cathodes for efficient electro-Fenton systems

Development of cathode materials with high activity, stability, and wide operating pH range is crucial for electro-Fenton reactions. Herein, mesoporous sulfur-modified metal oxides were coated onto stainless steel meshes and applied as a cathode to promote in-situ generation of H2O2 for electro-Fenton processes. Different mesoporous metal oxides with and without sulfur-modification were synthesized using Fe, Ni, and Zn precursors to investigate the effect of sulfur doping. Among them, sulfur doped Fe2O3 showed the best electrocatalytic performance, and it was attributed to several factors such as large specific surface area, high-efficiency oxygen reduction reaction activity, and enhanced electron/charge transfer. The effect of operational parameters such as applied voltage, catalyst dosage, initial pH, initial concentration of phenol, and electrolyte concentration on the catalytic performance was investigated in terms of degradation efficiencies and rate constants. The results indicate that for high concentration 100 ppm phenol solution, 78% removal efficiency with a rate constant of 0.186 h−1 was achieved with sulfur-doped Fe2O3 on stainless steel mesh electrode under optimal conditions in 8 h. This cathode worked effectively in a wide pH range (3–10) due to its pH self-control ability and exhibited superior stability and reusability with insignificant deterioration in the catalytic activity. This study offers an alternative approach to fabricate electrocatalysts with low-cost sulfur-doped metal oxides for electro-Fenton systems.

Smart harvesting and in-situ application of piezoelectricity in membrane filtration systems

Fouling remains one of the key challenges in membrane technology. In pressure-driven membrane separations, the vibrational energy induced by hydraulic pumps often dissipates unexploited. We present an innovative concept, in which the hydraulic pressure vibration is converted to electrical energy in the outlet of a filtration pump through an embedded piezoelectric nanogenerator (PENG) ceramic. We found that by increasing the average pressure of the hydraulic pump, the dynamic pressure fluctuation increased. The maximum output voltage of 219.6 V was obtained at 20 psi average pressure. The generated piezoelectricity was directly applied to an electro-assisted membrane cell in either alternating mode or positive/negative rectified form to mitigate membrane fouling. In the first configuration, ultrafiltration (UF) membrane was placed between two metallic electrodes. The optimum fouling resistance was achieved when the positive rectified piezoelectric pole was connected to the electrode. Water flux decline (FD) and water flux recovery ratio (FRR) were improved by 28.6% and 52.1%, respectively, compared to the case where no voltage was applied. In the second configuration, a piece of water-permeable and electro-conductive carbon nanotube (CNT) mat was mounted over the UF membrane and it was connected to the piezoelectric wafer using a wire. The alternating piezoelectricity provided the best antifouling performance in this configuration, with FD of 32.5% and FRR of 78.3%. The generated piezoelectricity was also used as a power source to drive an electro-Fenton (EF) reaction coupled with nanofiltration (NF) for reactive black 5 (RB5) dye separation. The results showed that the highest RB5 degradation rate (8.8%) was achieved when the rectified negative and positive poles were connected to the graphite paper and stainless-steel mesh electrodes, respectively. The proposed piezoelectric energy harvesting can revolutionize the traditional methods of fouling reduction in the electro-membrane processes where an external power should be applied for the oxidation reactions to occur.

Revealing the Role of Brønsted Basicity by the Electrocatalytic Reaction via Li Insertion in the MgFe2O4 Lattice

In this work, the impact of improving Brønsted basicity of the MgFe2O4 spinel lattice through Li substitution has been explored to ease out hydrogen evolution reaction (HER) or methanol oxidation reaction (MOR) by the unique compositions of electrocatalytic materials synthesized using a solvothermal method by varying the ratios of Li and Mg precursors. The substitution of Li+ at the Mg2+ lattice in the MgFe2O4 spinel was deliberated by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and Brunauer–Emmett–Teller analyses. The smaller-sized Li+ (alkali metal) ion substitution was enabled with ease as LixMg1–xFe2O4 led to increase in the Brønsted basicity as confirmed by pH studies. Among the prepared different electrocatalysts, the 3-D polyhedron chain-like Li0.5Mg0.5Fe2O4 loaded at a 316 stainless steel mesh electrode exhibits an enhanced electrocatalytic activity for HER or MOR. Importantly, the developed electrocatalyst needs an unresolved overpotential of 27 mV for HER activity which is very near to that of the bench mark Pt/C catalyst to reach a current density of 10 mA cm–2 and an excellent electrochemical activity for MOR with a current density of 171.3 mA cm–2. Besides, the faradaic efficiency for the Li0.5Mg0.5Fe2O4-loaded electrode was calculated as 97% that significantly revealed the existence of a synergistic effect between Li+ and Mg2+ ions where the effective participation of the Li and Mg lattice has enabled the spinel lattice to increase the Brønsted basicity and to enhance the electrocatalytic activities for HER or MOR.

Sono‐exfoliated graphene‐like activated carbon from hazelnut shells for flexible supercapacitors

Currently, more than 80% of commercial supercapacitors utilize chemically synthesized carbon nanomaterials which are expensive and necessitates non-renewable resources. Employing renewable, environment friendly and naturally available biomass feedstock as precursor for producing carbon materials is a low-cost and sustainable way for designing the electrodes of supercapacitors. In the present study, high surface area hierarchical porous multilayered graphene-like carbon is obtained via room temperature sono-exfoliation of the activated carbon synthesized via simple and environmentally friendly hydrothermal carbonization and potassium bicarbonate activation of waste hazelnut shells as the precursor. The high surface area graphene-like carbon showed excellent electrochemical performance with specific capacitance of 320.9 F g−1 at 0.2 A g−1 current density and exceptional capacitance retention of 77.8% at 2 A g−1 current density after 10 000 cycles in 1 M Na2SO4 electrolyte. Moreover, flexible supercapacitors fabricated using sono-exfoliated graphene-like activated carbon coated stainless steel mesh electrodes and biopolymer gel electrolyte exhibits an outstanding energy density of 38.7 W h kg−1 and power density of 198.4 W kg−1. These results show that mechanically exfoliated graphene-like activated carbon derived from hazelnut shells exhibit superior electrochemical performance that can compete with other activated carbon materials used in energy storage devices for real time applications.