Catalyst In Microbial Fuel Cell Research Articles

Harvesting Energy using Biocatalysts

<i>Harvesting Energy using Biocatalysts</i>

Sodium Cobalt Oxide As a Non-Platinum Cathode Catalyst for Microbial Fuel Cells

Microbial fuel cell is a device that can achieve wastewater treatment and power generation simultaneously. For the practical application of microbial fuel cell, development of alternative cathode catalyst for platinum is necessary. In this study, a kind of sodium cobalt oxide, NaCo2O4was investigated, because estimated cobalt reserve is 100 times higher than platinum, and its price is about one thousandth. Catalyst ink was prepared by mixing NaCo2O4powder with carbon black powder and Nafion dispersion. Then cathode was fabricated by applying the ink to PTFE treated carbon paper. Cathode with Pt catalyst and that with activated carbon (NORIT SX PLUS) were also prepared for comparison.ORR activity of the cathodes was measured by linear sweep voltammetry (LSV). Oxygen reduction reaction (ORR) activity of NaCo2O4 cathode increased 15-25 times by the addition of carbon black as conductive assistant material in catalyst ink. Two kinds of carbon black were tested, and a cathode with Ketjen black showed better ORR activity than that with Vulcan XC-72. By increasing coating amount of catalyst ink from 2mg/cm2 (NaCo2O4) to 4mg/cm2, ORR activity increased 1.6 - 1.7 times, which was equivalent to 50-60% of Pt catalyst (Fig) . Gram based ORR activity of this catalyst was higher than that of activated carbon (NORIT SX PLUS) catalyst (Fig). The NaCo2O4 cathode having highest ORR activity was built into a pre-acclimated MFC, and then used for the treatment of synthetic wastewater. The current density was about 3A/m2, which was a little lower than the value during the operation equipped with a Pt cathode (about 4A/m2). However, any problems such as a decrease in electricity generation were not observed in several days of operation. Power density curve of the MFC equipped with the NaCo2O4 cathode was obtained by the LSV measurement , and the maximum current density was 0.58 W/m2, which is about a half of the density achieved by a Pt cathode. Further research on the preparation condition of the cathode, such as the amount of conductive assistant material, the amount of binder, and the coating amounts of the catalyst ink, would probably contribute to further improve the cathode ORR activity, which would improve electricity generation performance of a MFC. Figure 1

The Role of Micropore and Mesoporous in Activated Carbon As Air-Cathode Catalyst in Microbial Fuel Cell for Oxygen Reduction Reaction

Porous structure of activated carbon (AC) is important for mass transfer and catalyst when AC is used as air-cathode catalyst in microbial fuel cell (MFC). In this work, several carbon samples including two kinds of micropore carbon and mesoporous carbon with different pore sizes are prepared as air-cathode catalyst layer to explore the role of micropore and mesoporous during the process of oxygen reduction reaction (ORR). The catalytic activities of all samples are tested by linear sweep voltammetry (LSV), Tafel and rotating disk electrode (RDE). Besides, these carbon materials are also analyzed by Nitrogen adsorption-desorption isotherms, air permeability test, In situ FTIR and H2 temperature programmed reduction. Among these carbon samples, AC shows the best ORR performance, because its mesoporous structure is benefit for oxygen pass and micropore structure can promote catalytic activity. Thus, the electrochemical performance of activated carbon contribute to the own functions of micropore and mesoporous.

One-Step Synthesis of Hydrangea-like Cu2O@N-Doped Activated Carbon As Air Cathode Catalyst in Microbial Fuel Cell

In present study electrochemical deposition technology was used to modify the activated carbon (AC) cathode with hydrangea-like Cu2O and notrogen simultaneously, and the performance was improved greatly. The maximum power density was 1613±25 mW m-2, 84% and 62% more than controls repsectively. The electrochemical performances of cathodes were evaluated by Linear sweep voltammetry, exchange current density (i0) and Electrochemical impedance spectroscopy. Hydrangea-like mophology provided more active sites and channels for electrons of oxygen reduction reaction. X-ray XRD, FTIR and XPS results the existence of oxygen vacancy, crystal defects, acidic functional groups and hydrophilic functional groups, and C-N bond, especially pyridine, pyrrole and quaternary N, played a significant catalytic role in oxygen reduction reaction. Electrodeposition is a promising way to modifi AC cathode with metal and nitrogen at the same time.

Iron-rich nanoparticle encapsulated, nitrogen doped porous carbon materials as efficient cathode electrocatalyst for microbial fuel cells

Developing efficient, readily available, and sustainable electrocatalysts for oxygen reduction reaction (ORR) in neutral medium is of great importance to practical applications of microbial fuel cells (MFCs). Herein, a porous nitrogen-doped carbon material with encapsulated Fe-based nanoparticles (Fe-Nx/C) has been developed and utilized as an efficient ORR catalyst in MFCs. The material was obtained through pyrolysis of a highly porous organic polymer containing iron(II) porphyrins. The characterizations of morphology, crystalline structure and elemental composition reveal that Fe-Nx/C consists of well-dispersed Fe-based nanoparticles coated by N-doped graphitic carbon layer. ORR catalytic performance of Fe-Nx/C has been evaluated through cyclic voltammetry and rotating ring-disk electrode measurements, and its application as a cathode electrocatalyst in an air-cathode single-chamber MFC has been investigated. Fe-Nx/C exhibits comparable or better performance in MFCs than 20% Pt/C, displaying higher cell voltage (601 mV vs. 591 mV), maximum power density (1227 mW m−2 vs. 1031 mW m−2) and Coulombic efficiency (50% vs. 31%). These findings indicate that Fe-Nx/C is more tolerant and durable than Pt/C in a system with bacteria metabolism and thus holds great potential for practical MFC applications.

Nitrogen-doped graphene/CoNi alloy encased within bamboo-like carbon nanotube hybrids as cathode catalysts in microbial fuel cells

Cost-effective catalysts are of key importance to the successful deployment of microbial fuel cells (MFCs) for electricity generation from organic wastes. Herein, a novel catalyst prepared by one-step synthesis strategy is reported. The catalyst features N-doped bamboo-like carbon nanotube (BCNT) in which CoNi-alloy is encapsulated at the end and/or the middle section of the tube with many graphene layers inside inner cavities of BCNT (N-G@CoNi/BCNT). The prepared N-G@CoNi/BCNT exhibits a high oxygen reduction reaction (ORR) activity with an early onset potential of 0.06 V vs. Ag/AgCl and a comparable exchange current density to that of commercial Pt/C. The excellent catalytic activity is further evidenced by a high electron transfer number of 3.63. When being applied in MFCs, the N-G@CoNi/BCNT yields an average current density of 6.7 A m−2, slightly lower than that of Pt/C but with a less mass transfer potential loss. The cost of the N-G@CoNi/BCNT for constructing a 1-m2 cathode electrode is 200 times lower than that of Pt/C. With such a competitive price and excellent electrocatalytic-activity resulting from its unique morphology, CoNi-alloy/nitrogen dopants, considerable specific surface area, and carbon-coated alloy/graphene hybridization, the present catalyst is a promising candidate for ORR catalysts in MFCs for energy recovery from wastes.

Carbon nanotube/polypyrrole nanocomposite as a novel cathode catalyst and proper alternative for Pt in microbial fuel cell

This study demonstrates the use of carbon nanotube polypyrrole (CNT/PPy) nanocomposite as a novel cathode catalyst in microbial fuel cells (MFC). The CNT/PPy nanocomposite has been prepared using a chemical oxidative method and its performance in MFC was evaluated and compared with platinum, the traditional cathode catalyst. The attachment of microorganisms on the anode was confirmed using field emission scanning electronic microscopy (FESEM) analysis. The size of ppy nanoparticles was also observed using SEM. Cyclic voltammetry (CV) studies were done to investigate the catalytic properties of CNT/PPy nanocomposite. The maximum power density and coulombic efficiency attained by the usage of CNT/PPy nanocomposite was found to be ∼113 mW/m2 and 21% respectively, which is a significant comparison with the Pt catalyst, where the measured values were 122.7 mW/m2 and 24.6% respectively. The COD removal of both systems was found to be more than 80%. The results indicate that CNT/PPy nanocomposite could be used as a possible lower cost alternative than Pt catalyst in MFC.

Morphology-dependent Performance of Nanostructured MnO2 as an Oxygen Reduction Catalyst in Microbial Fuel Cells

Morphology-dependent Performance of Nanostructured MnO2 as an Oxygen Reduction Catalyst in Microbial Fuel Cells

Optimization of Pt-Pd alloy catalyst and supporting materials for oxygen reduction in air-cathode Microbial Fuel Cells

ABSTRACT In this study, Pt-Pd alloy catalyst was fabricated on carbon papers via electro-deposition as an alternative catalyst for oxygen reduction in air-cathode Microbial Fuel Cells (MFCs). Effects of electro-deposition cycles and supporting materials (graphene and carbon nanotubes (CNTs)) on oxygen reduction reaction (ORR) activity of the Pt-Pd electrode and power generation in MFCs were investigated. The structural and electrochemical properties of the Pt-Pd catalyst were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Results showed that the Pt-Pd electrode showed a good ORR activity. A MFC with a Pt-Pd cathode of 15 deposition cycles produced a maximum power density of 1274 mWm −2 , comparable to that with a conventional Pt/C cathode (0.5 mg Pt cm −2 ). CNT as the supporting material further increased ORR activity of the Pt-Pd electrode and power generation capacity in MFCs, while graphene as the supporting material did not produce positive effects. XRD results confirmed the presence of Pt/Pd elements on the electrode. SEM results showed that decoration using CNT reduced Pt-Pd particle size and promoted them even dispersion on the carbon paper. The Pt-Pd electrode attained a comparable performance to the Pt/C electrode when controlling an optimum deposition cycles and using CNT as the supporting materials, which demonstrates the potential of replacing Pt as an oxygen reduction catalyst in MFCs due to high oxygen reduction activity and relatively low cost.

Production of Sustainable Energy by Carbon Nanotube/Platinum Catalyst in Microbial Fuel Cell

Platinum (Pt) is the most efficient and common cathode catalyst that is being applied in fuel cell technology, especially in microbial fuel cells (MFCs). However, its high price makes its use uneconomical in MFCs. Even though there are some other types of new catalysts, their performance could not compete with Pt. This is the main reason why scientists spend all their efforts to decrease the amount of Pt by making some composite of Pt for their use in MFCs thus making it viable and more economical. In this study, carbon nanotube-platinum (CNT/Pt) nanocomposite has been fabricated as a novel cathode catalyst in MFCs and its performance was compared with platinum in MFCs system. The CNT/Pt was synthesized by using the in situ method, and the performance is being compared in terms of power density generation in different concentration. The results have shown that CNT is a suitable support for catalyst in MFCs and CNT/Pt generally has better performance than Pt in MFCs. This can be due to better interaction with oxygen in the cathode chamber and high catalytic activity of CNT/Pt for oxygen reduction reaction. The potential of CNT/Pt nanocomposite in generating electricity from MFCs has been demonstrated and this can be a sustainable source of energy for the future.

Synthesis of iron oxide/partly graphitized carbon composites as a high-efficiency and low-cost cathode catalyst for microbial fuel cells.

Waste cornstalks and pomelo skins are used as carbon resources for preparing nanocomposites of iron oxide and partly graphitized carbon (Fe3O4/PGC-CS and Fe3O4/PGC-PS). The results showed that Fe3O4 with a face-centered cubic structure is uniformly dispersed on the skeleton of Fe3O4/GC, and the highest SBET values of Fe3O4/PGC-CS (476.5 m(2) g(-1)) and Fe3O4/PGC-PS (547.7 m(2) g(-1)) are obtained at 1000 °C. The electrical conductivity and density of catalytic active sites are correspondingly improved by the introduction of Fe species. Microbial fuel cells (MFCs) with a mixed composite (Fe3O4/PGC-CS:Fe3O4/PGC-PS = 1:1) cathode (three-dimensional structures) generate the highest power density of 1502 ± 30 mW m(-2), which is 26.01% higher than that of Pt/C (1192 ± 33 mW m(-2)) and only declines by 7.12% after 18 cycles. The Fe3O4/PGC-CS cathode has the highest Coulombic efficiency (24.3 ± 0.7%). The Fe3O4/PGC composites exhibit high oxygen reduction reactivity, low charge transfer resistances, and long-term stability and can be used as a low-cost and high-efficiency catalyst for MFCs.

Power generation using polyaniline/multi-walled carbon nanotubes as an alternative cathode catalyst in microbial fuel cells

SUMMARY Optimization of the cathode catalyst is critical to the study of microbial fuel cells (MFCs). By using the open circuit voltage and power density as evaluation standards, this study focused on the use of polyaniline (PANI)/multi-walled carbon nanotube (MWNT) composites as cathode catalysts for the replacement of platinum (Pt) in an air-cathode MFC, which was fed with synthetic wastewater. Scanning electron microscopy and linear scan voltammogram methods were used to evaluate the morphology and electrocatalytic activity of cathodes. A maximum power density of 476 mW/m2 was obtained with a 75% wt PANI/MWNT composite cathode, which was higher than the maximum power density of 367 mW/m2 obtained with a pure MWNT cathode but lower than the maximum power density of 541 mW/m2 obtained with a Pt/C cathode. Thus, the use of PANI/MWNT composites may be a suitable alternative to a Pt/C catalyst in MFCs. PANI/MWNT composites were initially used as cathodic catalysts to replace Pt/C catalysts, which enhanced the power generation of MFCs and substantially reduced their cost. Copyright © 2014 John Wiley & Sons, Ltd.

Nonactivated and Activated Biochar Derived from Bananas as Alternative Cathode Catalyst in Microbial Fuel Cells

Nonactivated and activated biochars have been successfully prepared by bananas at different thermotreatment temperatures. The activated biochar generated at 900°C (Biochar-act900) exhibited improved oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performances in alkaline media, in terms of the onset potential and generated current density. Rotating disk electron result shows that the average of 2.65 electrons per oxygen molecule was transferred during ORR of Biochar-act900. The highest power density of 528.2 mW/m2 and the maximum stable voltage of 0.47 V were obtained by employing Biochar-act900 as cathode catalyst, which is comparable to the Pt/C cathode. Owning to these advantages, it is expected that the banana-derived biochar cathode can find application in microbial fuel cell systems.

Potential of Root Crops as Source of Electrical Energy

Energy from edible and inedible root crop roots and tubers using galvanic cell and processing waste waters through microbial fuel cell (MFC) technology was harnessed. Electrolyte in the roots and tubers was tapped for galvanic cell and the microorganisms from waste waters act as catalyst in MFC. In galvanic cell, the optimized responses of badiang, cassava and sweetpotato were greatly affected by the surface area and distance between anode and cathode electrodes. An increase of nata-de-coco membrane size in MFC increased the voltage and current by 4.94 and 11.71 times, respectively. Increasing the width of anode also enhanced the responses. Different types of microorganisms were isolated from the biofilm anode of MFC. Their growth and proliferation which corresponded to the generation of electricity were also demonstrated in this study. A total of 54 bacterial isolates were collected from the biofilm at the anode of single-chamber MFC (SCMFC). The generated electricity observed using light emitting diodes (LED) showed potential both for galvanic and microbial fuel cell. The generated regression models are reliable tools in predicting desired outputs for future applications. These promising results demonstrated basic information on the electrical energy recovery from rootcrop waste waters and roots/tubers.

Porous nitrogen-doped carbon nanosheet on graphene as metal-free catalyst for oxygen reduction reaction in air-cathode microbial fuel cells

Porous nitrogen-doped carbon nanosheet on graphene (PNCN) was used as an alternative cathode catalyst for oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). Here we report a novel, low-cost, scalable, synthetic method for preparation of PNCN via the carbonization of graphite oxide–polyaniline hybrid (GO–PANI), subsequently followed by KOH activation treatment. Due to its high concentration of nitrogen and high specific surface area, PNCN exhibited an excellent catalytic activity for ORR. As a result, the maximum power density of 1159.34mWm−2 obtained with PNCN catalyst was higher than that of Pt/C catalyst (858.49mWm−2) in a MFC. Therefore, porous nitrogen-doped carbon nanosheet could be a good alternative to Pt catalyst in MFCs.

Use of Pyrolyzed Iron Ethylenediaminetetraacetic Acid Modified Activated Carbon as Air–Cathode Catalyst in Microbial Fuel Cells

Activated carbon (AC) is a cost-effective catalyst for the oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). To enhance the catalytic activity of AC cathodes, AC powders were pyrolyzed with iron ethylenediaminetetraacetic acid (FeEDTA) at a weight ratio of FeEDTA:AC = 0.2:1. MFCs with FeEDTA modified AC cathodes and a stainless steel mesh current collector produced a maximum power density of 1580 ± 80 mW/m(2), which was 10% higher than that of plain AC cathodes (1440 ± 60 mW/m(2)) and comparable to Pt cathodes (1550 ± 10 mW/m(2)). Further increases in the ratio of FeEDTA:AC resulted in a decrease in performance. The durability of AC-based cathodes was much better than Pt-catalyzed cathodes. After 4.5 months of operation, the maximum power density of Pt cathode MFCs was 50% lower than MFCs with the AC cathodes. Pyridinic nitrogen, quaternary nitrogen and iron species likely contributed to the increased activity of FeEDTA modified AC. These results show that pyrolyzing AC with FeEDTA is a cost-effective and durable way to increase the catalytic activity of AC.

Development and application of vanadium oxide/polyaniline composite as a novel cathode catalyst in microbial fuel cell

SUMMARY Polyaniline (Pani), vanadium oxide (V2O5), and Pani/V2O5 nanocomposite were fabricated and applied as a cathode catalyst in Microbial Fuel Cell (MFC) as an alternative to Pt (Platinum), which is a commonly used expensive cathode catalyst. The cathode catalysts were characterized using Cyclic Voltammetry and Linear Sweep Voltammetry to determine their oxygen reduction activity; furthermore, their structures were observed by X-ray Diffraction, X-ray Photoelectron Spectroscopy, Brunauer–Emmett–Teller, and Field-Emission Scanning Electron Microscopy. The results showed that Pani/V2O5 produced a power density of 79.26 mW/m2, which is higher than V2O5 by 65.31 mW/m2 and Pani by 42.4 mW/m2. Furthermore, the Coulombic Efficiency of the system using Pani/V2O5 (16%) was higher than V2O5 and Pani by 9.2 and 5.5%, respectively. Pani–V2O5 also produced approximately 10% more power than Pt, the best and most common cathode catalyst. It declares that Pani–V2O5 can be a suitable alternative for application in a MFC system. Copyright © 2013 John Wiley & Sons, Ltd.

Copper-phthalocyanine and nickel nanoparticles as novel cathode catalysts in microbial fuel cells

In this study, four different catalysts (i.e., carbon black, nickel nanoparticle (Ni)/C, Phthalocyanine/C and copper-phthalocyanine/C), were tested in a two-chamber Microbial Fuel Cell (MFC) and their performances were compared with Pt as the common cathode catalyst in MFC. The characterization of catalysts was done by TEM, XPS and EDX and their electrochemical characteristics were compared by cyclic voltammetry (CV) and Linear Sweep Voltammetry (LSV). The results proved that copper phthalocyanine and nickel nanoparticles are potential alternatives catalyst for Pt. Even copper-phthalocyanine generated power is almost the same as Pt. The CV and LSV results reported high electrochemical activity of these catalysts. The maximum power density and coulombic efficiency was achieved by copper-phthalocyanine/C as 118.2 mW/m2 and 29.3%.

Graphene Supported Pt-Co Alloy Nanoparticles as Cathode Catalyst for Microbial Fuel Cells

Graphene Supported Pt-Co Alloy Nanoparticles as Cathode Catalyst for Microbial Fuel Cells

Carboxyl Multi-Wall Carbon Nanotubes Supported Pt-Ni Alloy Nanoparticles as Cathode Catalyst for Microbial Fuel Cells

Carboxyl Multi-Wall Carbon Nanotubes Supported Pt-Ni Alloy Nanoparticles as Cathode Catalyst for Microbial Fuel Cells