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The polymer composite membranes based on sulfonated poly (ether ether ketone) (SPEEK) and strontium cerate (SrCeO3) were prepared by dispersing SrCeO3 nanoparticles into SPEEK solution with the solvent casting method. The prepared composite membranes are characterized by X-ray diffraction analysis, Fourier infrared spectroscopy, scanning electron microscopy, water uptake, ion exchange capacity, proton conductivity, methanol permeability, thermogravimetric analysis, and oxidative stability. Significant improvement has been attained through the successful combination of the organic and inorganic phases. TGA showed that all the composite membranes exhibited good thermal stability. The maximum proton conductivity of 32.1 mS/cm was achieved at (25 °C) upon incorporating 06 wt.% of the SrCeO3 nanoparticle. The excellent proton conductivity of the membranes can be attributed to the presence of SrCeO3 nanoparticles, which can act as pathways for proton transport. The prepared polymer composite membranes exhibited high selectivity compared with pure SPEEK and Nafion 117. From the observed results, the prepared 94 wt% SPEEK and 06 wt% SrCeO3 composite membranes can be considered opposite polymer electrolyte membranes for the application of direct methanol fuel cell (DMFC) applications. [ABSTRACT FROM AUTHOR]

The impact of methanol concentration on direct methanol fuel cell (DMFC) of 45 cm2 zones of activity was experimentally studied with serpentine channel field design. The performance of the DMFC was analyzed and the optimum methanol concentration was determined with a polarization curve. A recently suggested Coefficient Diagram derived from PI Controller (CD-PIC) was used to run the model-based DMFC in a closed loop with the manipulated variable as methanol concentration. The CD-PIC design is simple and efficient compared to the Bode Diagram-based controller design. It is also used to test the performance and robustness of the system apart from the stability. A recently suggested PI Controller that relies on a Coefficient Schematic is employed in DMFC operation. The progress of the proposed CD-PIC is evaluated under load abandonment circumstances and set point monitoring. Set point tracking and load rejection tests are carried out with step changes at different operating points. The controller execution is evaluated in ways of controller progress measuring (CPM) indices. The suggested performance metrics for the proposed CD-PIC indicate that it yields better performance for servo problems and regulatory problems which support the supremacy of CD-PIC. The robustness of the CD-PIC is also analyzed. From the CPM indices, it is concluded that the recently created CD-PIC for DMFC is found as highly robust. [ABSTRACT FROM AUTHOR]

The construction and assessment of an effective, cost-efficient anode catalyst for methanol oxidation reactions (MOR) are crucial in direct methanol fuel cells (DFMC) applications. This work unveils a quick, simple, yet effective method for synthesizing poly(aniline-co-pyrrole) using the "chemical oxidative polymerization" technique and creates an affordable and stable anode catalyst for DMFC applications. The chemical oxidative polymerization approach was employed to copolymerize aniline and pyrrole with incorporation of nickel, and the electrocatalyst showcased remarkable activity towards methanol oxidation reaction (MOR). Physiochemical characterizations such as scanning electron microscopy, FT-infrared spectroscopy, Raman spectroscopy, and thermogravimetric analysis were performed to validate the incorporation of transition metal nickel into the copolymerized conducting polymers (aniline-co-pyrrole), abbreviated as PANiPPy. Electrochemical techniques like cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy (EIS) were used to investigate the capability of the electrocatalysts to oxidize methanol in alkaline conditions. The electrode material NiPANiPPy displayed a higher oxidation current density 280.60 mA/cm2 from the cyclic voltammogram of the electrocatalysts in 1 M KOH + 1 M methanol compared to the other synthesised electrocatalysts since nickel provides a low onset potential while the copolymers PANiPPy provide good conductivity and mechanical stability. Moreover, NiPANiPPy exhibits the lowest current rate loss and a substantially higher current density among them after 3600 s with the highest current density of 100 mAcm−2. NiPANiPPy was also observed to have the lowest solution resistance with 0.8 Ω compared to other electrocatalysts in EIS spectra. Thus, the synthesized electrocatalysts has potential applications as an enhanced anode electrode for DMFC. [ABSTRACT FROM AUTHOR]

Direct Methanol fuel cells (DMFC) have been limited in their utilization due to their slow cathodic oxygen reduction reaction (ORR) kinetics and the expensive cost of commercial Pt/C catalysts. It is critical to design an oxygen reduction process with high-efficiency catalysts. An approach for modulating the ratio of cellulose, hemicellulose, and lignin in the wheat stalk (WS)/wheat stalk binder (WS binder) precursor materials is proposed in this work. WS binder from alkalization and hydrothermal treatment was added to the WS to change the structure and shape of WS-based carbon materials by varying the ratios, which increased the ORR catalytic activity. The half-wave potential (E 1/2) of the produced carbon material (15 wt% N/C (WS)) is 0.76 V, which was enhanced by 80 mV by adjusting the ratio of the WS/WS binder compared to 0 wt% N/C(WS). The E 1/2 of 15 wt% Fe–N/C (WS) (0.85 V) was greater than that of commercial Pt/C (0.84 V). Besides, its catalytic oxygen reduction process was close to the 4-electron transfer pathway and had good methanol tolerance. The power density obtained with a cathode catalyst of 15 wt% Fe–N/C (WS) for DMFC was 1.39 mW cm−2 at 30 °C and 3.33 mW cm−2 at 60 °C. At different temperatures, the power densities were 1.59 and 1.54 times greater than those of commercial Pt/C catalysts, respectively. [Display omitted] • Binders were added to wheat stalk carbon substrates to change their morphology and structure. • Introduction of Hemin-prepared iron single-atom catalysts with excellent ORR performance. • In DMFC, 15 wt% Fe–N/C(WS) demonstrated a good power density that was better than commercial Pt/C. [ABSTRACT FROM AUTHOR]

Bipolar flow channel plate design, which is a key component and performance qualifier of fuel cells, is an extensively investigated area. Recently, bio-inspired flow fields (FFs) have been designed to increase the overall performance as an alternative to traditional FFs. In the present study, performance evaluation of the various bio-inspired FFs was carried out in PEM fuel cell and direct methanol fuel cell modes. The effects of the main performance characteristics including the clamping force of the short stack assembly, air flow rate, and operating temperature on the cell power were investigated for both PEMFC and DMFC modes. The highest performance output was ensured with the Morus leaf-inspired FF (MLFF) at PEMFC mode at 55 °C with a peak power density of 313 mW/cm2. Besides, the highest performance for DMFC mode was achieved at 35.8 mW/cm2 with the Ficus Carica leaf-inspired FF (FCLFF). • Bio-inspired flow fields were fabricated considering Morus and Ficus Carica leaves. • Fabricated BPs were tested for both PEM and direct-methanol fuel cell modes. • Gas flow rate, operating temperature, and clamping force conditions were regarded. • In PEMFC mode, Morus leaf-inspired field yielded maximum power with 313 mW/cm2. • In DMFC mode, Ficus Carica leaf-inspired field had maximum power with 35.8 mW/cm2. [ABSTRACT FROM AUTHOR]

Nafion, a widely utilized commercial membrane in direct methanol fuel cells (DMFC), presents significant limitations due to its cost and susceptibility to high methanol crossover. This study explores alternative membranes, focusing on Sodium Alginate/Poly (Vinyl Alcohol) (SA/PVA) blends with montmorillonite (MMT) modification as an inorganic filler. The MMT content in the SA/PVA membrane was varied from 2 to 20 wt% using the solvent casting method. Optimally, 10 wt% MMT content demonstrated the highest proton conductivity (9.38 mScm−1) and the lowest methanol uptake (89.28%) at ambient temperature. The SA/PVA-MMT membrane exhibited superior thermal stability, optimal water absorption, and reduced methanol uptake, attributed to the electrostatic attraction within the sodium alginate and PVA polymer matrices interacting with H+, H3O+, and –OH ions. The homogeneous dispersion of 10 wt% MMT, along with its hydrophilic properties, facilitated an efficient proton transport channel in SA/PVA-MMT membranes. Increasing MMT content enhanced membrane hydrophilicity, indicating that 10 wt% MMT loading is crucial for adequate water intake to activate proton transfer. This study suggests that the developed membrane holds great potential as a cost-effective alternative with competent performance for future applications. [ABSTRACT FROM AUTHOR]

In this study, Pd/TiO2 decorated carbon nanofibers (Pd/TiO2@CNFs) and Pd@CNFs were prepared by the impregnation method for application in direct methanol fuel cells (DMFCs). Pd and TiO2 particles were supported on the surface of carbon fibers. Noticeably, When the mass fraction of PdCl2 added is 4%, the Pd@CNFs catalyst (Pd‐4@CNFs) showed higher electrocatalytic activity and stability, which were about 28.4 and 13.2 times higher than those of commercial Pd/C catalyst, respectively. On the basis of Pd‐4@CNFs catalyst, TiO2 with a mass fraction of 10% was added to produce Pd/TiO2@CNFs catalyst (Pd‐4/TiO2‐10@CNFs). The electrocatalytic activity of Pd‐4/TiO2‐10@CNFs increased to 3,850.4 A·g−1, which was 31.9 times higher than that of commercial Pd/C catalysts. These results demonstrated that the novel Pd/TiO2@CNFs catalyst is expected to be an efficient and durable catalyst for DMFC. [ABSTRACT FROM AUTHOR]

Fuel cells represent an appealing avenue for harnessing eco-friendly energy. While their fuel supply traditionally stems from water electrolysis, an environmentally conscious approach also involves utilizing low-weight alcohols like methanol and ethanol. These alcohols, concentrated from sustainable sources within the enological by-product distillation process, offer a noteworthy contribution to the circular economy. This study delved into evaluating the efficacy of distillery fractions in powering methanol fuel cells. Beyond their energy-generation potential, the performed GC-MS analysis unveiled appreciable quantities of acetic acid resulting from the partial oxidation of ethanol. This revelation opens the door to intriguing possibilities, including the recovery and repurposing of novel compounds such as short-chain fatty acids (predominantly acetic acid), ketones, and aldehydes—establishing a link between sustainable energy production and the emergence of valuable by-product applications. [ABSTRACT FROM AUTHOR]

Fuel cells represent an appealing avenue for harnessing eco-friendly energy. While their fuel supply traditionally stems from water electrolysis, an environmentally conscious approach also involves utilizing low-weight alcohols like methanol and ethanol. These alcohols, concentrated from sustainable sources within the enological by-product distillation process, offer a noteworthy contribution to the circular economy. This study delved into evaluating the efficacy of distillery fractions in powering methanol fuel cells. Beyond their energy-generation potential, the performed GC-MS analysis unveiled appreciable quantities of acetic acid resulting from the partial oxidation of ethanol. This revelation opens the door to intriguing possibilities, including the recovery and repurposing of novel compounds such as short-chain fatty acids (predominantly acetic acid), ketones, and aldehydes—establishing a link between sustainable energy production and the emergence of valuable by-product applications.

Sulfonated polysulfone (SPS) composite membranes consisting of cellulose-based carbon nanodots (CNDs) were successfully prepared as a proton exchange membrane (PEM) for direct methanol fuel cell (DMFC) applications. The CNDs were prepared using the top-down hydrothermal method. The structure transformation from cellulose to CNDs was confirmed by the FTIR and XRD analysis. The particle size of CNDs was between 1 and 3 nm. The particles exhibited good optical properties. The incorporation of CND into matrix polymer increased the thermal stability of the membranes. Morphology analysis of the SPS/CND composite membranes revealed that CNDs had been successfully dispersed within the SPS polymer matrix. The cross-linking between SPS and CNDs enhanced the proton conductivity of the composite membranes compared to the pristine SPS membrane. The SPS/CND-1 (1 wt%) exhibited the highest selectivity with a proton conductivity of 35.5 mS.cm−1 and a methanol permeability of 3.50 × 10−6 cm2.s−1. The experimental results indicate that the incorporation of CNDs into the SPS membrane also decreased the amount of methanol that can pass through the membrane when used in DMFCs.

In this paper, a novel numerical model of direct methanol fuel cells (DMFC) is proposed aiming to quantitatively analyze the effect of methanol, water, and oxygen mass transfer on the performance and to further improve power and reduce energy losses. The model was validated against experimental data. The model predicts the values of variation of reactant concentrations in each layer and the effect of parameters is analyzed. The results show that overall performance is better at low methanol concentration (1–2 mol/dm3). A rise in a certain temperature (65 K) increases maximum power density by 13.6%, ECOP by 43.9%, voltage efficiency by 13.6%, thermal efficiency by 14.2% and real efficiency by 19.1%, while reducing entropy yield by 19.3%. Moreover, the average of optimization results based on multi-objective particle swarm algorithm (MOPSO) indicated that maximum power density and its corresponding ECOP , and thermal efficiency were increased by 13.47%, 0.03%, and 6.21%, respectively. [Display omitted] • A novel numerical model of DMFC considering mass transfer is proposed. • The entropy production into overpotential losses and methanol crossover loss is investigated. • The model was validated against experimental data. • The model predicts the values of variation of reactant concentrations in each layer and the leakage current density. • The MOPSO algorithm and TOPSIS method are utilized to optimize the power density, ECOP, and thermal efficiency. [ABSTRACT FROM AUTHOR]

The electrocatalytic performance plays a pivotal role in the widespread adoption of DMFCs. Hence, it is imperative to develop electrocatalysts with superior performance for oxygen reduction reactions. In this study, carbon materials doped with Fe and Ni were synthesized. The characterization results revealed that the morphology, pore size, pore capacity, and BET of the catalysts varied with different doping elements, thereby affecting their performance. Linear Scan Voltammetry demonstrated that the doped samples (Ni−NC, Fe−NC, Fe−Ni−NC) exhibited varying degrees of enhancement in ORR activity compared to the undoped NC samples containing only Fe and Ni. Among them, the Fe−Ni−NC catalyst showed remarkable methanol tolerance (67.3 %) and a lower Tafel slope (93.24 mV dec−1) in comparison to the Pt/C catalyst (47.9 %). Moreover, RRDE measurements indicated a 3.31 % H2O2 yield and n of 3.93 for Fe−Ni−NC. Additionally, in DMFC tests conducted at 20 and 50 °C, Fe−Ni−NC approached the performance of the Pt/C catalyst cathode. [ABSTRACT FROM AUTHOR]

Polymer electrolyte membrane that has high proton conductivity and low methanol permeability are necessary for direct methanol fuel cells (DMFCs). A sodium alginate (SA)/polyvinyl alcohol (PVA)/montmorillonite (MMT)/graphene oxide (GO) quaternary composite membrane was effectively developed in this study. The homogeneous distribution of MMT and GO nanosheets in the SA/PVA/MMT/GO composite membrane was exhibited by scanning electron microscopy (SEM). Intriguingly, it has been established that the SA/PVA membrane contains chemical crosslinks between MMT and GO, which significantly contribute to the rise in proton conductivity. The SA/PVA/MMT/GO hybrid membrane has minimum loss modulus of 47.91% and storage modulus of up to 2.689 x 109 Pa, which are 3.8 times greater than those of SA/PVAMMT membrane without GO. This value indicates the viscosity and elasticity of the produced membrane. The quaternary composite membrane also exhibits outstanding oxidative stability and methanol barrier characteristics. The methanol permeability of SA/PVA/MMT/GO films 0.524 x 10-9 cm2 s-1, with methanol absorption as low as 9.72%. The best membrane performs at a highpower density (1.761 mW/cm2) of DMFC at a GO content of 1.3 wt% because it obtains the maximum selectivity value (7.0529 x 106 S scm-3). Future commercial membranes may be replaced by the innovative quaternary membrane created in this work, which has significant potential. [ABSTRACT FROM AUTHOR]

We synthesized molecular weight-controlled and fluorine-containing PAEs (MWCPAEs) using decafluorobiphenyl (DFBP), 2-bis (4-hydroxyphenyl) propane (Bis A), and 2,2-Bis (4-hydroxyphenyl) hexafluoropropane (Bis AF). Later, commercially available PEEK and the MWCPAEs were sulfonated (SPEEK and SMWCPAE) and blended to fabricate blend membranes (BMs). All BMs have been prepared by solution casting method in 5 wt%-20 wt% concentrations using N,N-dimethylacetamide. The effects of chemical structures, sulfonation levels, MW and compositions on the membrane properties are discussed. We obtained miscible and mechanically compatible BMs. The highest proton conductivity (238.9 mS/cm) was determined for SPEEK70/S-DFBP-Bis-A based blend membrane (M w : 48.355, 5wt. %). All chemical, mechanical, thermal, and hydrolytic properties of the BMs are comparable with, or better than, that of Nafion. We suggest that designing polymeric structures with desired MWs and sulfonation levels may enable enhanced properties and can help to design materials with on demand properties. [Display omitted] • Molecular weights controlled Poly (arylene ether)s has been synthesized and sulfonated. • The blend membranes we prepared are miscible and mechanically compatible. • The proton conductivity value up to 238.9 mS/cm has been obtained. • BMs properties are comparable with, or better than, that of Nafion. • The membranes are suitable for PEMFC and DMFC applications. [ABSTRACT FROM AUTHOR]

Nowadays, the development and utilization of clean energy are becoming increasingly urgent. Among them, methanol is a new, clean, and efficient energy source. Therefore, more and more studies are focusing on methanol anodic oxidation (MOR). In this work, nanoflower and hollow spherical NiO was synthesized by a simply hydrothermal method and then modified by Co ion, NiS2 and carbon nanotubes (CNTs). The optimal Co/NiO(f)/NiS2−CNT exhibits flower‐like morphology with a larger specific surface area, enlarged electrochemically active surface area and higher conductivity, which improve the electron transfer ability and electrocatalytic activity compared with pure NiO(f), NiO(f)/NiS2, NiO(f)/NiS2−CNT and hollow spherical Co/NiO(hs)/NiS2−CNT. The current density is ultrahigh of 203.46 mA ⋅ cm−2 at 0.8 V, which is 36 times higher than pure NiO(f) and almost 2 times higher than Co/NiO(hs)/NiS2−CNT. Therefore, this work offers a highly efficient and stable NiO based catalyst for methanol oxidation reaction. [ABSTRACT FROM AUTHOR]

The electrocatalyst of oxygen reduction reactions is one of the basic components of a fuel cell. In addition to costly Pt/C benchmark catalysts, cost-effective carbon-based catalysts have received the most attention. Enormous efforts have been dedicated to trade off the catalyst performance against the economic benefit. Optimizing composition and/or structure is a universal strategy for improving performance, but it is typically limited by tedious synthesis steps. Herein, we have found that directly introducing CNT into MOF-derived carbonaceous nanopolyhedra, i.e., introduced carbon nanotubes (CNTs) penetrated porous nitrogen-doped carbon polyhedra (NCP) dotted with cobalt nanoparticles (denoted as CNTs-Co@NCP), can optimize the catalytic activity, stability, and methanol tolerance. The hierarchical architecture combines the 0D/1D/3D Co/CNT/NCP interfaces and 1D/3D CNT/NCP junctions with the frameworks with a greatly exposed active surface, strengthened mass transport kinetics, stereoscopic electrical conductivity networks and structural robustness. The sterical self-consistency of MOF-self-assembly triggered by introduced CNTs demonstrates tactful ORR electrocatalytic activity regulation. Eventually, the CNTs-Co@NCP showed a half-wave potential (E1/2) of 0.86 V and a diffusion-limited current density (JL) of 5.94 mA/cm2 in alkaline electrolyte. The CNTs-Co@NCP was integrated into the cathode of a direct methanol fuel cell (DMFC) with an anion-exchange membrane, and an open-circuit voltage (OCV) of 0.93 V and a high power density of 46.6 mW cm−2 were achieved. This work successfully developed a catalyst with competitive ORR performance through plain parameter fine-tuning without complex material design. [ABSTRACT FROM AUTHOR]

One of the significant drawbacks of the Direct Methanol Fuel Cells is the overpotential for the methanol oxidation reaction, which strongly limits the efficiency of this fuel cell. Furthermore, CO poisoning of Pt is considered to be a severe problem for these devices. In this work, electrocatalysts with suitable properties and outstanding performance have been developed for the oxidation reaction of methanol. PtCu and PtCuRu type materials have been synthesized through a relatively uncomplex, fast, highly reproducible, and easily scalable method. In turn, these materials have been subjected to a selective chemical dissolution process to enrich their surface with a higher density of active sites and surface defects. Evidence of alloy formation was found, specifically through XPS measurements on Ru 3d level. Besides, it was observed that with the trimetallic catalysts, which contain not only Cu but also Ru, the onset of CO electrooxidation is substantially reduced. Moreover, the leaching treatment further improves this value. This same trend was observed in the evaluation of methanol oxidation. Regarding the specific and mass activities, PtCuRu-le exhibits almost 240% and 195% higher SA and MA than commercial Pt, respectively. [ABSTRACT FROM AUTHOR]

Nafion is a commercial membrane that is widely used in direct methanol fuel cells (DMFC) but has critical constraints such as being expensive and having high methanol crossover. Efforts to find alternative membranes are actively being carried out, including in this study, which looks at producing a Sodium Alginate/Poly (Vinyl Alcohol) (SA/PVA) blended membrane with modification by montmorillonite (MMT) as an inorganic filler. The content of MMT in SA/PVA-based membranes varied in the range of 2.0–20 wt% according to the solvent casting method implemented. The presence of MMT was seen to be most optimal at a content of 10 wt%, achieving the highest proton conductivity and the lowest methanol uptake of 9.38 mScm−1 and 89.28% at ambient temperature, respectively. The good thermal stability, optimum water absorption, and low methanol uptake of the SA/PVA-MMT membrane were achieved with the presence of MMT due to the strong electrostatic attraction between H+, H3O+, and −OH ions of the sodium alginate and PVA polymer matrices. The homogeneous dispersion of MMT at 10 wt% and the hydrophilic properties possessed by MMT contribute to an efficient proton transport channel in SA/PVA-MMT membranes. The increase in MMT content makes the membrane more hydrophilic. This shows that the loading of 10 wt% MMT is very helpful from the point of view of sufficient water intake to activate proton transfer. Thus, the membrane produced in this study has great potential as an alternative membrane with a much cheaper cost and competent future performance. [ABSTRACT FROM AUTHOR]

Fuel cells operated with a reformate fuel such as methanol are promising power systems for portable electronic devices due to their high safety, high energy density and low pollutant emissions. However, several critical issues including methanol crossover effect, CO-tolerance electrode and efficient oxygen reduction electrocatalyst with low or non-platinum usage have to be addressed before the direct methanol fuel cells (DMFCs) become commercially available for industrial application. Here, we report a highly active and selective Mg−Co dual-site oxygen reduction reaction (ORR) single atom catalyst (SAC) with porous N-doped carbon as the substrate. The catalyst exhibits a commercial Pt/C-comparable half-wave potential of 0.806 V (versus the reversible hydrogen electrode) in acid media with good stability. Furthermore, practical DMFCs test achieves a peak power density of over 200 mW cm−2 that far exceeds that of commercial Pt/C counterpart (82 mW cm−2). Particularly, the Mg−Co DMFC system runs over 10 h with negligible current loss under 10 M concentration methanol work condition. Experimental results and theoretical calculations reveal that the N atom coordinated by Mg and Co atom exhibits an unconventional d -band-ditto localized p -band and can promote the dissociation of the key intermediate *OOH into *O and *OH, which accounts for the near unity selective 4e− ORR reaction pathway and enhanced ORR activity. In contrast, the N atom in SAC Co remains inert in the absorption and desorption of *OOH and *OH. This local coordination environment regulation strategy around active sites may promote rational design of high-performance and durable fuel cell cathode electrocatalysts. [ABSTRACT FROM AUTHOR]

Remarkable progress has been made to develop proton exchange membrane for direct methanol fuel cell to achieve higher power density. However, the higher methanol cross-over and poor water management are the two major obstacles of fuel cell which significantly reduces its performance. In this work, we have developed a highly performance Ionic Liquid (IL) modified chitosan based composite membrane and characterized by different experimental technique. The incorporation of IL in the chitosan composite introduces cationic acid which increases the ion exchange capacity and proton conductivity. Although the hydrophilic base of IL enhances water uptake capacity of the composite, the water is strongly attached with the polymer chain via hydrogen bonding thereby reducing free water content. The incorporation of Carbon Nanotubes (CNT) and bulky pendant group of IL in the chitosan composite reduces methanol cross-over and the methanol cross-over reported for CPCN@IL-4 composite (5.58 × 10–8 cm2sec−1) is significantly lower than the commercial N117 membrane (2.74 × 10–6 cm2sec−1). The IL modified composite membrane provides higher proton conductivity and membrane selectivity which is desirable for fuel cell design. At 70 °C, the maximum proton conductivity was achieved in CPCN@IL-3 composite (21.52 × 10–4 Scm−1) and the proton transport was controlled by bound water regulated Grotthus mechanism. The polarization curve obtained for CPCN@IL-3 composite at 70 °C and 2 M methanol feed in a single cell of fuel cell provides the maximum power density of 82 mW/cm2 at a current density of 370 mA/cm2. The modification of chitosan based composite membrane with CNT and IL significantly reduces the methanol cross-over and provides higher membrane selectivity which will attracted a possible candidate for DMFC application. [ABSTRACT FROM AUTHOR]

We used a new strategy to develop a hybrid membrane by impregnating hygroscopic zirconia and ionic liquid in the chitosan-PVA blend. The effects of ionic liquids on the water uptake, IEC, phase transition behavior, methanol permeability, and proton conductivity of the hybrid membrane were studied. The ionic liquids have a synergetic effect on the chain flexibility and tensile strength of the thin film. The developed hybrid membrane has the lowest methanol permeability of 0.94 × 10−7 cm2s−1. The polarization curve obtained for a fuel cell operating at 70°C and 2 M methanol feed provides the maximum power density of 97 mWcm−2. [ABSTRACT FROM AUTHOR]

Catalyst layers made from novel catalysts must be fabricated in a way that the catalyst can function to its full potential. To characterize a PtNi alloy catalyst for use in the cathode of Direct Methanol Fuel Cells (DMFCs), the effects of the manufacturing technique, ink composition, layer composition, and catalyst loading were here studied in order to reach the maximum performance potential of the catalyst. For a more detailed understanding, beyond the DMFCs performance measurements, we look at the electrochemically active surface area of the catalyst and charge-transfer resistance, as well as the layer quality and ink properties, and relate them to the aspects stated above. As a result, we make catalyst layers with optimized parameters by ultrasonic spray coating that shows the high performance of the catalyst even when containing less Pt than commercial products. Using this approach, we can adjust the catalyst layers to the requirements of DMFCs, hydrogen fuel cells, or polymer electrolyte membrane electrolysis cells. [ABSTRACT FROM AUTHOR]

A series of proton exchange electrolytes were synthesized by blending polystyrene sulfonic acid (PSSA) functionalized ZWP ion exchanger and sulfonated poly(vinylidene fluoride) (SPVDF) as base by using solution casting method. The poly(vinylidene fluoride) was sulfonated by employing a direct sulfonation technique demonstrated in the literature. Surface modification of the ZWP was done to obtain the PSSA-ZWP ion exchanger. The membranes were synthesized by using ZWP and PSSA-ZWP as ion exchangers in the SPVDF polymer matrix. The physicochemical characterization of the membranes was performed by using FT-IR and XRD. The scanning electron microscope (SEM) was used to investigate the surface morphology of the fabricated membranes for any possible defects. Important membrane parameters, such as water uptake (up to 26%), methanol uptake (up to 22%), chemical stability (7.4%) and mechanical stability (tensile strength of up to 44 MPa), were measured and are reported. The ion exchange capacity (max 0.62 meq g−1) and electrochemical characterization of the membranes was conducted and parameters such as transport number (max 0.84) indicating good ion selectivity of the membranes and proton conductivity (max 3.89 mS/cm) were also determined. The single cell DMFC performance of the SPVDF-ZWP-PSSA membrane was evaluated at three different operating temperatures of 30 °C, 60 °C and 90 °C, out of which the synthesized membrane performed best at 60 °C with maximum current density and power density of 49.8 mAcm−2 and 20.1 mWcm−2 respectively. • SPVDF based composite PEMs were fabricated using ZWP & ZWP-PSSA as ion-exchanger. • Water uptake and methanol uptake results are comparable to Nafion 117. • PEM showed good mechanical stability of 44 MPa and good chemical stability. • Transport no. of 0.84, IEC of 0.62 meq g−1 & conductivity of 3.8 mS/cm were obtained. • Current density of 49.87 mA/cm2 & power density of 20.1 mW/cm2 obtained at 60 °C. [ABSTRACT FROM AUTHOR]

A noble metal-free atomically dispersed dual metal (Fe and Mn) anchored nitrogen (N)-doped reduced graphene oxide (rGO) is synthesized as a high-performance oxygen reduction reaction (ORR) electrocatalyst for alkaline direct methanol fuel cell and aluminium-air battery (AAB). The as-synthesized FeMn-NrGO catalyst exhibits a half-wave potential of 0.84 V for ORR and a low onset potential of 0.96 Vvs (RHE). The theoretical study reveals that the synergetic coupling of Mn and Fe with pyridinic and pyrrolic nitrogen weakening adsorption bond strength of the O* intermediates to the active site of the catalyst, thereby improving the for ORR performance. The synthesized Fe 3 Mn 1 -NrGO cathode catalyst assembled alkaline direct methanol fuel cell (DMFC) demonstrates a peak power density of 65 mW/cm2 extending an effective strategy to enhance the ORR kinetics of the non-noble metal-based catalyst for fuel cell application. Furthermore, the synthesized Fe 3 Mn 1 -NrGO also exhibits excellent ORR activity in 3.5 wt% NaCl solution and demonstrates a peak power density of 11.2 mW/cm2 aqueous NaCl electrolyte-based AAB system. [Display omitted] • The ORR activity was optimized by dual Fe and Mn atoms anchored on nitrogen-doped reduced graphene oxide • The atomically dispersed Fe and Mn interaction with different N-sites is studied for ORR. • The effect of chloride ions for ORR as well as single-cell aqueous Al-air battery is explored. [ABSTRACT FROM AUTHOR]

The electrocatalyst of oxygen reduction reactions is one of the basic components of a fuel cell. In addition to costly Pt/C benchmark catalysts, cost-effective carbon-based catalysts have received the most attention. Enormous efforts have been dedicated to trade off the catalyst performance against the economic benefit. Optimizing composition and/or structure is a universal strategy for improving performance, but it is typically limited by tedious synthesis steps. Herein, we have found that directly introducing CNT into MOF-derived carbonaceous nanopolyhedra, i.e., introduced carbon nanotubes (CNTs) penetrated porous nitrogen-doped carbon polyhedra (NCP) dotted with cobalt nanoparticles (denoted as CNTs-Co@NCP), can optimize the catalytic activity, stability, and methanol tolerance. The hierarchical architecture combines the 0D/1D/3D Co/CNT/NCP interfaces and 1D/3D CNT/NCP junctions with the frameworks with a greatly exposed active surface, strengthened mass transport kinetics, stereoscopic electrical conductivity networks and structural robustness. The sterical self-consistency of MOF-self-assembly triggered by introduced CNTs demonstrates tactful ORR electrocatalytic activity regulation. Eventually, the CNTs-Co@NCP showed a half-wave potential (E1/2) of 0.86 V and a diffusion-limited current density (JL) of 5.94 mA/cm2 in alkaline electrolyte. The CNTs-Co@NCP was integrated into the cathode of a direct methanol fuel cell (DMFC) with an anion-exchange membrane, and an open-circuit voltage (OCV) of 0.93 V and a high power density of 46.6 mW cm−2 were achieved. This work successfully developed a catalyst with competitive ORR performance through plain parameter fine-tuning without complex material design.

In this work, a novel co-deposited nano spherical polydiphenylamine-palladium supported graphitic carbon nitride (GCN/PDPA/Pd NS) nanohybrid was fabricated via the in-situ one-pot electrochemical co-deposition method. The GCN/PDPA/Pd NS nanohybrid electrode was characterized by morphology studies, which found that the average diameter of the PDPA/Pd nanospherical size is 250 nm over the graphitic carbon nitride nano matrix as well as elemental composition, structural and vibrational spectra also observed through FESEM, EDX, Mapping, and XRD, FT-IR studies. The electrochemical characterizations of the GCN/PDPA/Pd NS electrocatalyst were studied using cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopic techniques. The fabricated GCN/PDPA/Pd NS–modified electrode shows significant electrocatalytic activity, lower oxidation potential (− 0.15 V), high stability, and longevity (1800s) towards methanol oxidation reaction (MOR) in an alkaline medium. The fabricated GCN/PDPA/Pd NS electrocatalyst is a significant anode catalyst for the direct methanol fuel cell application. [ABSTRACT FROM AUTHOR]

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Nafion is a commercial membrane that is widely used in direct methanol fuel cells (DMFC) but has critical constraints such as being expensive and having high methanol crossover. Efforts to find alternative membranes are actively being carried out, including in this study, which looks at producing a Sodium Alginate/Poly (Vinyl Alcohol) (SA/PVA) blended membrane with modification by montmorillonite (MMT) as an inorganic filler. The content of MMT in SA/PVA-based membranes varied in the range of 2.0–20 wt% according to the solvent casting method implemented. The presence of MMT was seen to be most optimal at a content of 10 wt%, achieving the highest proton conductivity and the lowest methanol uptake of 9.38 mScm−1 and 89.28% at ambient temperature, respectively. The good thermal stability, optimum water absorption, and low methanol uptake of the SA/PVA-MMT membrane were achieved with the presence of MMT due to the strong electrostatic attraction between H+, H3O+, and −OH ions of the sodium alginate and PVA polymer matrices. The homogeneous dispersion of MMT at 10 wt% and the hydrophilic properties possessed by MMT contribute to an efficient proton transport channel in SA/PVA-MMT membranes. The increase in MMT content makes the membrane more hydrophilic. This shows that the loading of 10 wt% MMT is very helpful from the point of view of sufficient water intake to activate proton transfer. Thus, the membrane produced in this study has great potential as an alternative membrane with a much cheaper cost and competent future performance.

The polymer electrolyte membrane and its contact with electrodes has a significant effect on the performance of fuel and electrolysis cells but the choice of commercially available membranes is limited. In this study, membranes for direct methanol fuel cells (DMFCs) were made by ultrasonic spray deposition from commercial Nafion solution; the effect of the drying temperature and presence of high boiling solvents on the membrane properties was then analyzed. When choosing suitable conditions, membranes with similar conductivity, water uptake, and higher crystallinity than comparable commercial membranes can be obtained. These show similar or superior performance in DMFC operation compared to commercial Nafion 115. Furthermore, they exhibit low permeability for hydrogen, which makes them attractive for electrolysis or hydrogen fuel cells. The findings from our work will allow for the adjustment of membrane properties to the specific requirements of fuel cells or water electrolysis, as well as the inclusion of additional functional components for composite membranes.

This paper aims to identify the irreversibilities in the condenser of a direct methanol fuel cell (DMFC) system and present possible enhancements in its design through local entropy generation analysis (L-EGA). For this purpose, the local entropy generation terms originating from heat and mass calculated from results of a pseudo two-phase computational fluid dynamic (CFD) model of the condenser. Through this analysis, the total irreversibilities due to heat and mass transfer are calculated locally (e.g., film boundary layer, vapour-gas boundary layer) under the variable operating conditions of a DMFC (undersaturated, saturated, and supersaturated conditions of the cathode exhaust gas). Moreover, the exergy destruction ratio of condenser is found to estimate the exergy performance of the condenser. The results show that in the case of supersaturated cathode exhaust gas (CEG) flow, the entropy generation rate due to mass transfer in the film region is found as 0.032 W/(m·K) which is 18 times higher than that for the undersaturated CEG flow. However, entropy generation rate due to mass transfer decreases significantly when the hot flow is just over the film region. In the film region, the entropy generation rates originating from heat transfer are found as 0.0055 W/(m·K) (for the undersaturated case), 0.0032 W/(m·K) (for the saturated case), and 0.0015 W/(m·K) (for the supersaturated case). Moreover, the maximum exergy destruction ratio is found as 0.72 when the CEG is undersaturated and the CEG velocity is 0.18 m/s, while the lowest exergy destruction ratio is calculated as 0.28 when the CEG is saturated. • The local entropy generation analysis for a condenser in a DMFC system to reveal avoidable exergy losses. • The post-processing of CFD model for the analysis. • Strong capability to reveal minimum and maximum entropy generation source hot points locally. • Entropy generation due to heat transfer, mass transfer, and coupled heat and mass transfer. [ABSTRACT FROM AUTHOR]

It is critical and challenging to start direct methanol fuel cells (DMFCs) from various environmental states to an ideal operating state by a sensor-less method. This paper presents a novel methanol sensor-less startup control (SLSC) algorithm based on the unimodal relationship of current vs. methanol concentration at a constant cell voltage during DMFC startup. A series of experiments indicate that the SLSC algorithm is capable of starting a DMFC under various initial concentrations and initial temperatures and can be easily adjusted to reduce the startup time or improve the energy efficiency. The wide applicability and easy adjustment characteristics give the SLSC algorithm a potential prospect in the DMFC system.

[Display omitted] • A detailed review of modified PVDF and its copolymer based proton exchange membrane for DMFC is explained. • The physical and electrochemical characteristics of PVDF and its copolymer-made membranes are discussed. • The advantages of these different polymers for making membranes are compared. • The future prospects for improvement in this polymer membrane are highlighted. Direct methanol is a promising portable electronic device that converts chemical energy into electrical energy by using easily available and environmentally friendly methanol fuel. Among its different components, the proton exchange membrane (PEM) is responsible for continuing the flow of hydration ions from anode to cathode, protecting from fuel crossover and keeping the electrons pushing towards the external circuit, which produces power. The Nafion-based proton exchange membrane is widely studied in direct methanol fuel cells because of its easy wettability, high ion exchange capacity, minimum methanol crossover, and mechanical strength due to its nono-porous structure. However, the methanol crossover increases in the Nafion membrane due to easy swelling when temperature raise due to reactions in the direct methanol fuel cells (DMFC) and dramatically reduces overall cell performance. Several types of polymers have been applied as PEMs for the replacement of costly Nafion membranes. Among these polymers, polyvinylidene fluoride (PVDF) and its copolymers such as polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and poly (vinylidene fluoride-chlorotrifluoroethylene) (PVDF-CTFE) are considered effective for the production of high-class proton exchange membranes because of their less swollen nature, easy film forming ability, high mechanical strength, thermal stability and chemical inertness. Their easy modification with other hydrophilic polymers and nanoparticles as well as surface functionalization convert their hydrophobic nature that boosts proton conductivity. Moreover, the nano-porous structure with tortuous paths create with PVDF and copolymers efficiently reduces the methanol crossover. From high-crystalline PVDF to reduced-crystalline copolymers, effects on mechanical strength and water uptake of the proton exchange membrane. This review article presents the overall application of all PVDF family polymers and their modified forms as proton exchange membranes in direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The structure and morphology of corn stalk carbon substrates were modified by adding binders. • DFT showed that the Fe N active site responded favorably to ORR. • 15 wt% Fe N/C(CS) showed satisfactory power density in ZAB and DMFC, which was superior to commercial Pt/C. To enhance the large-scale manufacture of zinc-air batteries (ZAB) and direct methanol fuel cells (DMFC), high-performance oxygen reduction reaction (ORR) catalysts must be developed. In this study, corn stalk binder (CS binder) was added to corn stalk (CS), the ratio between the two was adjusted, and the structure and morphology of the carbon material was altered to create a biocarbon substrate material (15 wt% N/C (CS)) with ORR catalytic activity. It had a half-wave potential (E 1/2) that was 29 mV greater than the pure carbon substance from CS (0 wt% N/C(CS)). Using Fe and N coordination-Hemin, an iron single-atom catalyst (15 wt% Fe N/C (CS)) was created based on this. Commercial Pt/C catalysts are anticipated to be replaced by the 15 wt% Fe N/C (CS), which demonstrated exceptional peak power density in both DMFC and ZAB cell tests. The catalytic mechanism of 15 wt% Fe N/C (CS) is explained by density functional theory (DFT), whereby the 15 wt% N/C (CS) carbon substrate rich in faulty structures creates space for the effective use of the iron single-atom reactive sites. Furthermore, the Fe N sites reduced the overpotential of ORR, which promoted the adsorption and reduction of oxygen molecules at the active sites. [ABSTRACT FROM AUTHOR]

Composite chitosan/phosphotungstic acid (CS/PTA) with the addition of TiO2 and Al2O3 particles were synthesized to be used as proton exchange membranes in direct methanol fuel cells (DMFCs). The influence of fillers was assessed through X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, liquid uptake, ion exchange capacity and methanol permeability measurements. The addition of TiO2 particles into proton exchange membranes led to an increase in crystallinity and a decrease in liquid uptake and methanol permeability with respect to pristine CS/PTA membranes, whilst the effect of the introduction of Al2O3 particles on the characteristics of membranes is almost the opposite. Membranes were successfully tested as proton conductors in a single module DMFC of 1 cm2 as active area, operating at 50 °C fed with 2 M methanol aqueous solution at the anode and oxygen at the cathode. Highest performance was reached by using a membrane with TiO2 (5 wt.%) particles, i.e., a power density of 40 mW cm−2, almost doubling the performance reached by using pristine CS/PTA membrane (i.e., 24 mW cm−2).

Summary: In direct methanol fuel cell (DMFC) anode microchannels, the retention of CO2 leads to an anodic polarization reaction. Controlling CO2 discharge in the anode channel by a direct current (DC) electric field is beneficial for reducing the anodic polarization reaction. In this work, numerical simulation was the main scientific research method, and the leaky dielectric model was used to characterize the effect of the electric field force. An unsteady theoretical model was established by bidirectionally coupling the electric field and multiphase flow field, which, for this research, indicates the formation of CO2 Taylor bubble flow in a methanol aqueous solution within a DMFC anodic microchannel. Based on this theoretical model, the regulation mechanism of the DC electric field on the dynamic behavior of Taylor bubble formation in DMFC anode microchannels was studied. In the anode channel, the electric field increases the likelihood that the neck of the CO2 bubble will fracture during Taylor bubble formation. The higher electric field intensity increases the formation rate of CO2 bubbles and reduces their size. In addition, the electric field reduces the number of satellite bubbles in the anode channel and promotes the mass transfer rate of the methanol aqueous solution. The results show that the movement characteristics of CO2 can be effectively controlled by applying a DC electric field in the DMFC anode microchannel, which provides a new way to reduce the anodic polarization effect of the DMFC. [ABSTRACT FROM AUTHOR]

Summary: Ionic liquids (ILs) are promising solvents for catalytic and electrolyte applications, gas absorption, and extractions in electrochemical systems due to their useful features, such as high conductivity and good thermal, chemical, and electrical stability. This review focuses on incorporating ILs into fuel cell (FC) systems, specifically into two main components of FC (ie, polymer electrolyte membrane and electrocatalyst). In FC, a polymer electrolyte membrane with excellent conductivity and deprived of humidity even at high temperatures must be created for effective early commercialization of this technology. Electrocatalyst performance can also be enhanced with additive materials, such as ILs, thus further improving the entire achievement of FCs. This work discusses the most important reasons for ongoing studies and outlines the current progress in using ILs as a revolutionary form of polymer electrolyte membrane and electrocatalyst. [ABSTRACT FROM AUTHOR]

The current work investigates the efficiency of a Direct Methanol Fuel Cell (DMFC) by using COMSOL. The set-up model takes into consideration the electrochemical kinetics and chemical reactions. The anode catalyst layers are a main element in the PEM fuel cell; their porosity significantly affects the fuel cell efficiency. We focus on the impact of catalytic layers porosity on the battery efficiency. As claimed by the results, the porosity of catalytic layer greatly affects the performance of the battery. In addition, better output performance of µDMFC may be obtained when the catalytic layer porosity is chosen as εACL=0.009-0.1. The distributions of methanol, carbon dioxide, water, oxygen, polarization, and the current density are plotted to highlight the impact of porosity on the global performances. [ABSTRACT FROM AUTHOR]

Background: Recent evidence suggests that the dorsal medial frontal cortex (dMFC) may make an important contribution to perceptual decision-making, and not only to motor control. Objective/hypothesis: By fitting psychometric functions to behavioural data after TMS we tested whether the dMFC is critical specifically for the precision and/or bias of perceptual judgements. Additionally we aimed to disentangle potential roles of the dMFC in dealing with perceptual versus response switching. Methods: A subjective visual vertical task (SVV) was used in which participants weight visual (and other, e.g., vestibular) information to establish whether a line is oriented vertically. To ensure a high perceptual demand (putatively necessary to demonstrate a dMFC involvement) SVV lines were presented inside pop-out targets within a visual search array. Distinct features of perceptual performance were analysed before as compared to following theta-burst TMS stimulation of the dMFC, a control site, or no stimulation, in three groups, each of 20 healthy participants. Results: dMFC stimulation improved the precision of verticality judgments. Moreover, dMFC stimulation improved accuracy, selectively when response switches occurred with perceptual repeats. Conclusion: These findings point to a causal role of the dMFC in establishing the precision of perceptual decision making, demonstrably dissociable from an additional role in motor control in attentionally demanding contexts.

The synthesis of anode electrocatalyst with high activity and durability for methanol oxidation reaction has been one of the main focuses of researchers in recent years. Several works are reviewed in this paper to summarize and compare the performance of electrocatalysts comprising of noble and non-noble metals. The effect of manipulating catalysts by introducing nanostructured morphology, metal alloys, support materials, acidic or basic electrolyte, and synthesis methods are also examined. The paper finally concludes with details of challenges that are generally faced in making direct methanol fuel cell (DMFC) a reliable source of energy for future prospects, and the approach to be taken to reduce the complexity in synthesizing new generations of anode electrocatalysts. [ABSTRACT FROM AUTHOR]

In this work, we have successfully cross-linked the different weight ratio of Chitosan-PVA blend with sulfuric acid. The effect of cross-linker on the properties of blends are studied by using different experimental technique. The cross-linked membrane provides higher ion exchange capacity due to the procurement of extra ionic hooping sites in the membrane. The compatibility of the blends are confirmed from the FTIR and DSC analysis. The crosslinking reaction fastening the phase transition behavior of the blends which reduces the glass transition temperature. The highly compatiblized cross-linked blend provides higher tensile strength and lower modulus at moderate temperature. The significant reduction of weight loss was observed in a cross-linked membrane which enhances thermal stability of the blend. The group which are responsible for higher methanol cross-over are consumed by the cross-linking reaction and a drastic reduction of methanol cross-over was observed. The proton conductivity of the blends are obtained by performing experiment in a four probe impedance analyzer and fitting the EIS data in an equivalent circuit model. At moderate temperature, the cross-linked membrane provides higher proton conductivity than the pure membrane and the proton transport was controlled by Grotthus mechanism. The cross-linked membrane provides higher proton conductivity and membrane selectivity which is beneficial for DMFC design. [ABSTRACT FROM AUTHOR]

Custom‐made nanocomposite proton exchange membranes (PEMs) are fabricated using the blends of sulfonated chitosan (S‐Chitosan) and sulfonated graphene oxide (SGO) nanosheets for direct methanol fuel cells (DMFCs). Sulfonation of chitosan and GO are carried out by 1,3‐propane sultone and sulfanilic acid, respectively. Scanning electron microscope (SEM) with energy dispersive X‐ray investigation revealed that the thick, folded and wrinkled sheet‐like morphology of SGO and the existence of elemental sulfur. SEM and atomic force microscopy images showed the uniform dispersion of hydrophilic SGO nanosheets. Besides the S‐Chitosan/SGO membranes showed higher water uptake, swelling ratio and ion exchange capacity due to the enhancement in hydrophilicity. The modified PEMs displayed improvement in proton conductivity since the ion‐exchangeable sulfonic acid groups facilitate the proton conduction and effectively resist the methanol permeability by forming a strong hydrogen bond network with chitosan and thus diminish the void volume. Particularly, S‐Chiotsan‐1 membrane showed superior proton conductivity of 4.86 × 10−3 Scm−1 at (25°C), selectivity of 1.89 × 105 Scm−3 s and lesser methanol permeability of 2.57 × 10−8 cm2s−1. Overall results suggest that the S‐Chitosan/SGO membranes found to be a suitable alternate for Nafion® in DMFCs. [ABSTRACT FROM AUTHOR]

This study investigates the utilization of different compositions of Fe2O3 and polyvinyl alcohol (PVA) to modify chitosan in order to prepare a composite membrane. The membranes were synthesized using the phase inversion method and extensively characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), mechanical properties analysis, and water uptake analysis, whereby SEM was used to confirm the morphology of the composite membranes. Different electrochemical properties such as ion exchange capacity, proton conductivity, and methanol permeability of these membranes were also measured. The results showed that increasing the PVA mass improved the water uptake, ion exchange capacity (IEC), and proton conductivity because the PVA addition increased the hydrophilicity of the membrane; thus, the pore surface on the membrane was more open, which also caused higher membrane permeability. However, the methanol permeability values of all composite membranes were lower than that of Nafion. The highest IEC and proton conductivity were obtained for the CS-PVA-H3070 membrane, with values of 4.300 meq/g and 6.71 × 10−2 S·cm−1, respectively. The mechanical strength of these membranes showed that the PVA addition increased the elongation break and decreased the tensile strength of the membrane. The results imply that the chitosan membrane modified with PVA and Fe¬2O3 has a potential for DMFC applications.

Catalyst layers made from novel catalysts must be fabricated in a way that the catalyst can function to its full potential. To characterize a PtNi alloy catalyst for use in the cathode of Direct Methanol Fuel Cells (DMFCs), the effects of the manufacturing technique, ink composition, layer composition, and catalyst loading were here studied in order to reach the maximum performance potential of the catalyst. For a more detailed understanding, beyond the DMFCs performance measurements, we look at the electrochemically active surface area of the catalyst and charge-transfer resistance, as well as the layer quality and ink properties, and relate them to the aspects stated above. As a result, we make catalyst layers with optimized parameters by ultrasonic spray coating that shows the high performance of the catalyst even when containing less Pt than commercial products. Using this approach, we can adjust the catalyst layers to the requirements of DMFCs, hydrogen fuel cells, or polymer electrolyte membrane electrolysis cells.

A flower-like binary transition metal oxide, in the form of MgCo 2 O 4 , was successfully synthesized and investigated by XRD and Raman spectroscopy as well as by SEM and TEM micrographs. A hybrid of MgCo 2 O 4 with reduced graphene oxide (rGO) was prepared to distinguish between the rGO-riched and rGO-free catalysts for potential applications in direct methanol fuel cell (DMFC) anodes (methanol electro-oxidation process). The synergetic effect due to the proximity of magnesium and cobalt oxides, along with their hybridization on the rGO, makes MgCo 2 O 4 -rGO an efficient and low-cost catalyst for an anode electrode in the DMFC applications. EIS, CV, LSV tests, and cyclic stability of MgCo 2 O 4 -rGO for 2000 subsequent CV cycles confirm the pivotal role of rGO in the catalyst structure. Finally, the single-cell test indicated the suitability of our proposed catalyst for practical applications of DMFC. Indeed, the single-cell polarization diagrams show a significantly improved power density for single cells with MgCo 2 O 4 -rGO-based anode (19 mW cm−2) compared to MgCo 2 O 4 - based anode (11 mW cm−2). [ABSTRACT FROM AUTHOR]

In this work, a metal free polyaniline nanorod (PANI-NR) with graphitic carbon nitride (GCN) nanocomposite has been synthesized by solar irradiation approach an acidic medium without the assistance of any surfactant and template. As synthesized PANI-NR/GCN nanocomposite was characterized by morphology studies, which found that the average diameter of the PANI-NR was 500 to 600 nm and the length of the nanorod range from 3 to 3.5 µm where GCN randomly dispersed on the surface of PANI-NR. The elemental composition, structural and vibrational spectra of PANI-NR/GCN are observed through EDX, Mapping, XRD, and FT-IR studies. Subsequently, the synthesized PANI-NR/GCN nanocomposite was used as an electrocatalyst, which was characterized through cyclic voltammetry, impedance, and chronoamperometric studies. The fabricated PANI-NR/GCN modified electrode shows significant electrocatalytic activity, lower charge resistance, high stability, and longevity towards methanol oxidation reaction (MOR) in an alkaline medium. [ABSTRACT FROM AUTHOR]