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Nafion, the predominant choice for polymer electrolyte membranes (PEMs) in direct methanol fuel cells (DMFCs), excels in proton conductivity but is plagued by elevated methanol permeability and sustained performance degradation. To address these issues, this study aims to synthesize a self-healable composite membrane composed of sulfonated poly (ether ether ketone), polyvinyl alcohol, and sulfonated silica (S/PVA/S–SiO 2). The composite membrane with 3 wt% S–SiO 2 demonstrates the highest proton conductivity, thanks to its improved water absorption and increased proton transfer sites. Compared to pure SPEEK, the composite membrane has a 20% lower methanol permeability. With its enhanced selectivity, the S/PVA/S–SiO 2 membrane produces a power density of 3.64 mW cm−2 at 26.67 mA cm−2. Furthermore, by virtue of reversible hydrogen bonding, the composite membrane shows exceptional self-healing capabilities, restoring its methanol-blocking function by 83.6%. These results highlight that the S/PVA/S–SiO 2 membrane holds promise for DMFC applications. • S –SiO 2 increases water absorption and boosts proton conductivity. • Composite membrane with 3 wt% S –SiO 2 achieves the highest selectivity. • S/PVA/S–SiO 2 membrane self-heals due to reversible hydrogen bonding. • Self-healing restores 83.6 % of methanol-blocking and 89 % of power output. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Dalton Transactions: An International Journal of Inorganic Chemistry," published by The Royal Society of Chemistry. It includes various articles on topics such as metal-organic frameworks, electrochemical water oxidation, and photothermal conversion. The journal aims to connect the world with the chemical sciences and invest profits back into the chemistry community. [Extracted from the article]

Fe–N–C catalysts are considered promising substitutes for Pt-based catalysts at the cathode in direct methanol fuel cells (DMFCs) owing to their great methanol tolerance. However, Fe–N–C-based DMFCs commonly suffer from a decreased performance under extremely high methanol concentrations and exhibit poor stability, while the underlying mechanism remains controversial. In this study, a self-degradation phenomenon in a passive Fe–N–C-based DMFC was investigated in detail. The DMFC with an optimized ionomer content and catalyst loading delivered an extremely high peak power density of 28.85 mW cm−2 when fed with 3 M methanol solution, while the peak power density of the cell rapidly declined to 16.61 mW cm−2 after standing for 10 days without any discharging operation. Several electrochemical measurements were designed and conducted to explore the mechanism for this phenomenon. The results of these measurements revealed that methanol molecules are chemically adsorbed on the surface of the Fe–N–C catalyst, and the bonding cannot be reversed using simple physical methods, leading to the isolation of active sites from oxygen. Herein, we provide a new perspective on passive Fe–N–C-based DMFCs that would be significant for the technological development of portable power devices. [ABSTRACT FROM AUTHOR]

Owing to the directional electron transfer from Pt to MoO 2- x , the hydrogen adsorption at Pt site and the hydrogen binding energy at O site were optimized resultantly the significant enhancement of HOR performance as well as the CO tolerance due to the Mo-OH species formed in Pt-MoO 2-x -C. [Display omitted] Hydrogen oxidation reaction (HOR) as the anode reaction in proton exchange membrane fuel cell, usually suffers from the high loading of platinum (Pt) and subsequent CO poisoning especially by using industrial crude hydrogen as fuel. In this work, we propose a directional electron transfer route from Pt to MoO 2- x in the macroporous structure to significantly enhance the HOR activity as well as the CO tolerance, which is constructed by interface engineering and defect strategy to anchor highly dispersed Pt nanoparticles onto the three-dimensional MoO 2- x -C framework. The optimized 2Pt-MoO 2- x -C with 1.02 wt% Pt demonstrates higher HOR peak current density (3.57 mA cm−2) and nearly 25 times higher mass activity than 20 wt% Pt/C. The excellent HOR performance is attributed to the synergistic effect between Pt and MoO 2- x species, in which the charge transfer from Pt to MoO 2- x improves H 2 adsorption ability of Pt and accelerates the activation of H 2 due to the reduced hydrogen binding energy of MoO 2- x caused by Pt-O construction, leading to the release of H* thereby the enhancement of HOR activity. The construction of three-dimensional macroporous structure enhances the HOR dynamics by promoting the conductivity, mass transfer and the exposure of active sites. Moreover, the formed Mo-OH in Pt-MoO 2- x -C can effectively react with CO species to remove the CO poisoning of Pt, endowing the excellent CO tolerance. [ABSTRACT FROM AUTHOR]

The valuable formation of ternary nanocomposite electrocatalysts with a combination of less expensive transition metal oxides, demonstrated exceptional electrocatalysis process and long-term durability performance towards the methanol oxidation reaction (MOR) in the application of active direct methanol fuel cell (DMFC). The ternary electrocatalysts through the combination among Pt 2 –Pd 3 alloy, rGO and different tunable content of ceria were successfully produced via a simple and facile single-step hydrothermally aided reduction of formic acid procedure. The produced ternary nanocomposite electrocatalyst's suitability as an anode electrocatalyst in favour of the electrocatalytic efficiency of MOR performance is extensively investigated along with the significant effects of varying ceria loadings (0.30 wt% - 0.90 wt%). The results clearly demonstrated that more efficient and active of MOR occurred on the surface of ternary electrocatalyst with an optimal ceria amount of 0.45 wt%. Meanwhile, the DMFC testing evaluation based on the EC0.45–40 wt% provides distinguishably better DMFC performance with the highest power density value of 112.64 mW cm−2 achieved compared to the commercial electrocatalysts at 60 °C. Therefore, based on the DMFC performance results, the produced EC0.45–40 wt% demonstrated a very promising and remarkable anode electrocatalyst that can be employed in DMFC. • EC0.45 has exhibited excellent electrocatalytic performance towards MOR. • Excellent stability and durability obtained by EC0.45 towards MOR. • EC0.45–40 wt% exhibited highest power density value of 112.64 mW cm−2 at 60 °C. [ABSTRACT FROM AUTHOR]

Using ammonia as an efficient and quick co-precipitant, pure BaCeO 3 (BCO) and Cu doped barium cerate, BaCe 1-x Cu x O 3 (BCCO), with x = 0.02–0.16 mol%, were formulated. XRD and SEM were used to characterize the impact of copper on phase and morphology, respectively. XRD exhibited cubic phase for both BCO and BCCOs. The uniformity of the nanosized particles was established by SEM. The electrocatalytic ability of the BCCO for methanol electro-oxidation (MOR) was investigated by cyclic voltammetry (CV) in acidic medium with BCOs-modified Pt-electrode. The deduced kinetic (k sh , Do) and thermodynamic (Ea, ΔG, ΔH, ΔS) parameters indicated faster MOR kinetics with 4.1x10 −6 cm s−1 (k sh) and 2.51x10 −11 cm2 s−1 (Do), respectively using BaCe 0.96 Cu 0.04 O 3 (BCCO-1). This result is evidently coupled with the higher specific surface area of the nanosized perovskite. Peak currents were increased by over four orders of magnitude from 19.97 to 81. 51 mAcm−2 with methanol concentration and temperature from 20 to 50 °C. BCCO-1 with the lowest value of ΔG (-33. 40 kJmol-1) exhibited superior thermodynamics in acidic medium. The electrocatalytic activity and temperature-dependent stability of BCCOs strongly indicate their potential for use in direct methanol fuel cells (DMFCs). [Display omitted] • Pure and Cu doped barium cerate synthesized by co-precipitation method. • Doping of transition metals enhances the stability significantly. • Electrochemical methanol oxidation is the main reaction in PEMFCs. • Methanol electro-oxidation was investigated by cyclic voltammetry. [ABSTRACT FROM AUTHOR]

It is considerably significant and challenging to prepare platinum (Pt)-based catalysts with high activity and stability for the development of direct methanol fuel cells (DMFCs). On that account, we used Pt nanoparticles (NPs) as the core, coated zeolitic imidazolate framework-8 (ZIF-8), silicon dioxide (SiO2) and Pt NPs on their surfaces. Afterward, the SiO2 was etched away to prepare Pt-based nanomaterials with core-shell structure, which were named Pt@ZIF-8/Pt. Simultaneously, the electrocatalytic properties of Pt@ZIF-8/Pt nanomaterials catalyzing methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) were tested under alkaline conditions. The mass and specific activities of Pt@ZIF-8/Pt-12 for MOR were 3285.07 mA mgPt−1 and 1.12 mA cm−2 correspondingly. The limiting current densities (LCD), initial potentials (Eonset) and half-wave potentials (E1/2) for the catalytic ORR of sample Pt@ZIF-8/Pt-12 were 6.24 mA cm−2, 1.04 V and 0.83 V, respectively. Last but not least, zinc-air battery was assembled utilizing the Pt@ZIF-8/Pt-12 catalyst. The open circuit potential and maximum power density of the zinc-air battery were 1.48 V and 120.8 mW cm−2. As evidently demonstrated by our research findings, it still maintained excellent stability after 600 h of cyclic charge and discharge tests. As a result, this research not only provides enlightening guidance for catalyst design for DFMCs and zinc-air batteries, but also accelerates the development of new battery catalyst materials. [ABSTRACT FROM AUTHOR]

[Display omitted] Although Platinum (Pt)-based alloys have garnered significant interest within the realm of direct methanol fuel cells (DMFCs), there still exists a notable dearth in the exploration of the catalytic behavior of the liquid fuels on well-defined active sites and unavoidable Pt poisoning because of the adsorbed CO species (CO ads). Here, we propose an electronegativity-induced electronic redistribution strategy to optimize the adsorption of crucial intermediates for the methanol oxidation reaction (MOR) by introducing the Co element to form the PtCo alloys. The optimal PtCo hollow nanospheres (HNSs) exhibit excellent high-quality activity of 3.27 A mg Pt −1, which is 11.6 times and 13.1 times higher than that of Pt/C and pure Pt, respectively. The in-situ Fourier transform infrared reflection spectroscopy validates that electron redistribution could weak CO adsorption, and subsequently decrease the CO poisoning adjacent the Pt active sites. Theoretical simulations result show that the introduction of Co optimize surface electronic structure and reduce the d-band center of Pt, thus optimized the adsorption behavior of CO ads. This study not only employs a straightforward method for the preparation of Pt-based alloys but also delineates a pathway toward designing advanced active sites for MOR via electronegativity-induced electronic redistribution. [ABSTRACT FROM AUTHOR]

The growing demand for sustainable energy solutions highlights the need for advancements in electrocatalysts for direct methanol fuel cells (DMFCs). This study introduces a novel approach to enhance the efficiency and durability of nickel sulfide (NiS) catalysts. We developed a hierarchically porous structure integrated with reduced graphene oxide (rGO) on a nickel foam substrate. Using a dynamic hydrogen bubble template (DHBT) technique, we created a porous nickel scaffold. We then electrodeposited graphene oxide and NiS onto this scaffold, resulting in a hybrid structure termed NiS-rGO-Ni/NF. Characterization through SEM, XRD, and XPS confirmed that the catalyst has a highly porous structure with uniformly distributed Ni 3 S 2 and Ni 3 S 4 phases. The NiS-rGO-Ni/NF catalyst showed significant improvements over conventional NiS/NF. It achieved a peak current density of 84.10 mA/cm2 in the presence of 0.1 M methanol, compared to 30.32 mA/cm2 with NiS/NF. This enhancement is due to the porous nickel layer created using DHBT and the integration of rGO. Additionally, the NiS-rGO-Ni/NF catalyst demonstrated superior reaction kinetics, evidenced by a decrease in the Tafel slope from 204 mV/dec to 122 mV/dec. It also exhibited a remarkable increase in the electrochemically active surface area, reaching 179 cm2 compared to 22 cm2 for NiS/NF. These improvements in surface area and kinetics contribute to its excellent stability, with the catalyst maintaining consistent performance over 20 h of continuous operation. These results underscore the effectiveness of the NiS-rGO-Ni/NF catalyst in methanol oxidation and its potential for more efficient and stable electrochemical applications. • A novel NiS-rGO-Ni/NF electrode for efficient methanol oxidation reaction. • Porous structures and rGO integration enhance electron transfer and surface area. • DFT study reveals efficient non-CO pathways on Ni 3 S 2 and Ni 3 S 4 surfaces. • Electrode keeps 92% of activity after 1000 CV cycles, showing high stability. • Reduced charge transfer resistance confirms superior performance of NiS-rGO-Ni/NF. [ABSTRACT FROM AUTHOR]

The ultrafine PtNiRu ternary alloy nanowires exhibit exceptional catalytic activity and durability for both oxygen reduction reaction and methanol oxidation reaction. The incorporation of Ru modulates the d-band center of Pt atoms, facilitating the desorption of oxygenated intermediates and enhancing stability through the formation of robust Pt Ru metal bonds. [Display omitted] Direct methanol fuel cells rely on the efficiency of their anode/cathode electrocatalysts to facilitate the methanol oxidation reaction and oxygen reduction reaction, respectively. Platinum-based nanocatalysts are at the forefront due to their superior catalytic properties. However, the high-cost, scarcity, and low CO tolerance of platinum pose challenges for the scalable application of DMFCs. Herein, we report novel ultrathin ternary PtNiRu alloy nanowires to improve Pt utilization and CO tolerance. These novel electrocatalysts incorporate the oxophilic metal Ru into ultrathin PtNi nanowires, aiming to enhance the intrinsic activity of platinum while leveraging the long-term durability and high utilization efficiency provided by the bimetallic synergistic effect. The PtNiRu NWs significantly enhance both mass activity and specific activity for ORR, performing about 6.9 times and 3.9 times better than commercial Pt/C, respectively. After a rigorous durability test of 10,000 cycles, the PtNiRu NWs only exhibited a 25.2 % loss in mass activity. Additionally, for MOR, the MA and SA of PtNiRu NWs exceed that of Pt/C catalyst by 4.30 and 2.72 times, respectively, and exhibit exceptional resistance to CO poisoning. Theoretical insights from density functional theory calculations suggest that the introduction of Ru modulates the d-band center of the surface Pt atoms, which contributes to decreased binding strength of oxygenated species and an elevated dissolution potential, substantiating the enhanced performance metrics, and the durability enhancement stems from the stronger Pt M bonds than those in PtNiRu NWs resulted from Pt Ru covalent interactions. These findings not only provide a new perspective on platinum-based nanocatalysts but also significantly advance the quest for more efficient and durable electrocatalysts for DMFCs, representing a substantial stride in fuel cell technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • A strategy for MOF-composite nanofiber with synergistic architecture is proposed. • PU@PAN/UiO-66 core/shell nanofiber is prepared by coaxial electrospinning. • 3D proton-conduction networks are constructed in proton exchange membrane. • Sulfamic acid is successfully introduced on nanofiber. • The maximum power density of Nafion/S@NF-50 exhibits 182.6 mW cm−2. Proton exchange membranes (PEMs) play an important role in fuel cells. For realizing a nanofiber (NF) structure design in PEMs, the material should have tunable pores and a high specific area. In this study, we attempt to design a novel NF with synergistic architecture doped MOF for constructing three-dimensional (3D) proton conduction networks in PEMs. In this framework, UiO-66-COOH serves as a platform for proton sites to synergistically promote proton conductivity via polyvinylpyrrolidone dissolution, hydrolyzation of polyacrylonitrile, and sulfamic acid functionalization of the shell-layer NF. Benefiting from enriched proton-transfer sites in NFs, the obtained composite membrane overcomes the trade-off among proton conductivity, methanol permeability, and mechanical stability. The composite membrane with 50 % fiber (Nafion/S@NF-50) exhibited a high proton conductivity of 0.212 S cm−1 at 80 °C and 100 % relative humidity, suppressed methanol permeability of 0.66 × 10−7 cm2 s−1, and the maximum power density of direct methanol fuel cell is 182.6 mW cm−2. Density functional theory was used to verify the important role of sulfamic acid in proton transfer, and the activation energy barriers under anhydrous and hydrous conditions are only 0.337 and 0.081 kcal, respectively. This study opens up new pathways for synthesizing NF composite PEMs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrafine Pt 1 Ru 3 alloys were successfully embedded into the mesoporous carbon hollow spheres (MCHS). • Pt 1 Ru 3 @MCHS delivers superior electrocatalytic activity and excellent CO-poisoning tolerance towards the MOR. • The Pt single atom site over the Ru nanoparticles for Pt 1 Ru 3 @MCHS shows strong CH 3 OH adsorption. • The Pt single atom site over the Ru nanoparticles can promote CO removal due to the modified electronic structure. Active and durable electrocatalysts are essential for commercializing direct methanol fuel cells. However, Pt-based catalysts, extensively utilized in the methanol oxidation reaction (MOR), are suffered from resource scarcity and CO poisoning, which degrade MOR activity severely. Herein, Pt 1 Ru x bimetallic catalysts were synthesized by confining Pt 1 Ru x alloys within the shells of mesoporous carbon hollow spheres (MCHS) via a vacuum-assisted impregnation method (Pt 1 Ru x @MCHS). The confinement effect induced by mesoporous carbon hollow spheres resulted in a robust structure of Pt 1 Ru 3 @MCHS with an ultrafine dispersion of alloy nanoparticles. The experimental and theoretical results confirmed that the boosting electrocatalytic activity and stability of the MOR over Pt 1 Ru 3 @MCHS were contributed to the regulated electronic structure as well as the superior CO tolerance of atomic Pt site caused by the electronic interaction between single Pt atoms and Ru nanoparticles. This strategy is versatile for the rational design of Pt-based bimetallic catalysts and has a positive impact on MOR performance. [ABSTRACT FROM AUTHOR]

The effective design and construction of high-performance methanol oxidation reaction (MOR) electrocatalysts are crucial for the advancement of direct methanol fuel cells. However, the active sites of MOR electrocatalysts are prone to poisoning by CO, leading to severely decayed durability. Herein, a Ni-atomically dispersed PtRu alloy catalyst is prepared via electrodeposition on stainless steel mesh (PtRuNi/SS) for CO-resistant MOR. DFT calculations reveal that the PtRu alloy with atomically dispersed Ni could adjust the electronic configuration of Pt and facilitate bond breaking between hydrogen and carbon, decreasing the binding energy of *CO. The calculation results could be clearly verified by the electrochemical attenuated total reflection infrared spectroscopy and CO stripping experiments. Consequently, PtRuNi/SS exhibits a mass activity of 0.95 A mg−1Pt for the MOR, which is 1.9 and 4.3 times that of PtRu/SS (0.51 A mg−1Pt) and commercial Pt/C (0.22 A mg−1Pt), respectively. Moreover, PtRuNi/SS demonstrates promising MOR stability, retaining 86.4% of its current density in comparison with 68.9% for PtRu/SS and 53.8% for Pt/C during accelerated durability tests. The excellent CO resistance even endows PtRuNi with robust activity in the oxidation of other alcohols like ethanol. [ABSTRACT FROM AUTHOR]

The absence of stable and highly active non-precious metal electrocatalysts as a substitute to precious metal i.e., Pt (state-of-the-art) for methanol oxidation reaction in the application of direct methanol fuel cell considerably impedes the commercialization of these energy devices. In this work the electrocatalytic investigation of Fe-In MOF and its g-C3N4-based composites (i.e., 5–8 wt% g-C3N4@ Fe-In MOF) for methanol oxidation is reported. All the catalysts were prepared via solvothermal method. XRD, SEM, EDX, and FTIR were used to characterize the Fe-In MOF and its 5–8wt% g-C3N4 composites. In comparison to other prepared g-C3N4 based Fe-In MOF composites, the 7wt% g-C3N4 @ Fe-In MOF catalyst showed much greater electrochemical activity (i.e., 95.54 mA/cm2) and stability of 72.45% in 1 M NaOH and 3 M CH3OH. Due to graphitic carbon nitride specified high catalytic activity, intercalation, ion exchange, and redox properties. Further, the availability of iron (Fe) and indium (In) may also show a significant role in enhancing the electrocatalytic performance of 7wt% g-C3N4 @ Fe-In MOF over Fe-In MOF. They could be viewed as stable and economical electrocatalysts due to their numerous advantageous characteristics in structure, content, and nitrogen doping level. [ABSTRACT FROM AUTHOR]

The current challenge with sulfonated aromatic polymer proton exchange membranes (PEMs) lies in their inability to enhance proton conductivity, mechanical strength and methanol resistance concurrently. To address this issue, a novel approach has been taken by synthesizing hydrophobic polysulfone grafted with hydrophilic sulfonated polyvinyl alcohol (PSU-g-SPVA) through Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization. This graft polymer is then utilized as a modified material for PEMs in direct methanol fuel cells (DMFCs). The morphology of phase separation within the Nafion matrix is significantly influenced by the proportion of PSU-g-SPVA. Notably, the Nafion/PSU-g-SPVA-40 modified demonstrates superior alcohol resistance, with a methanol permeability rate of 2.32 × 10−7 cm2/s. Furthermore, due to its outstanding proton conductivity, the proton selectivity of this modified membrane is an impressive 10.9 × 104 S s/cm3, which significantly surpasses that of the standard Nafion membrane at 2.82 × 104 S s/cm3. Grafting techniques of hydrophobic main chain and hydrophilic side chains open up a new method for the blending of polymers with huge polarity differences. [ABSTRACT FROM AUTHOR]

A direct borohydride fuel cell (DBFC) is constructed using ethylene-vinyl acetate (EVA) binder-based carbon-supported Pt anode and KBH4 as fuel under hybrid cell configuration to overcome various problems and to achieve long-endurance performance. Multiphase electrochemical processes strongly depend on the structure and properties of an electrode surface, i.e., multiple-phase electrochemical interfaces. The reactions of the multiphase processes can be varied by changing an electrode surface. Upon variation of the surface, its hydrophilic/hydrophobic properties can be changed. DBFC utilizes a hydrophilic Pt/C anode and Pt-Co-Cr/C cathode with Nafion®(N115) membrane. KBH4 is used as a fuel instead of NaBH4 to achieve a lower fuel crossover and a better cathode performance. A peak power density of 41–42 mW cm−2 is achieved with air as an oxidant and anolyte as KBH4 (5 wt%) in KOH (20 wt%) at ambient temperature at a feed rate of 20 mL min−1. The DBFC delivers a stable voltage and power output with a current density of around 83 mA cm−2 and a voltage of around 0.50 V over a run time of 160 h with multiple start-stop cycles (in a 16 h single go run). This study proves the applicability of DBFC as an efficient and reliable power source for portable device applications. [ABSTRACT FROM AUTHOR]

Platinum (Pt) and palladium (Pd) are crucial in hydrogen energy technologies, especially in fuel cells, due to their high catalytic activity and chemical stability. Pt-Pd nanoparticles, produced through various methods, enhance catalytic performance based on their size, shape, and composition. These nanocatalysts excel in direct methanol fuel cells (DMFCs) and direct ethanol fuel cells (DEFCs) by promoting alcohol oxidation and reducing CO poisoning. Pt-Pd catalysts are also being explored for their oxygen reduction reaction (ORR) on the cathodic side of fuel cells, showing higher activity and stability than pure platinum. Molecular dynamics (MD) simulations have been conducted to understand the structural and surface energy effects of PdPt nanoparticles, revealing phase separation and chemical ordering, which are critical for optimizing these catalysts. Pd migration to the surface layer in Pt-Pd alloys minimizes the overall potential energy through the formation of Pd surface monolayers and Pt-Pd bonds, leading to a lower surface energy for intermediate compositions compared to that of the pure elements. The potential energy, calculated from MD simulations, increases with a decreasing particle size due to surface creation, indicating higher reactivity for smaller particles. A general contraction of the average distance to the nearest neighbour atoms was determined for the top surface layers within the nanoparticles. This research highlights the significant impact of Pd segregation on the structural and surface energy properties of Pt-Pd nanoparticles. The formation of Pd monolayers and the resulting core–shell structures influence the catalytic activity and stability of these nanoparticles, with smaller particles exhibiting higher surface energy and reactivity. These findings provide insights into the design and optimization of Pt-Pd nanocatalysts for various applications. [ABSTRACT FROM AUTHOR]

This work presents a comparative study of three synthesis methods for PtRu/C catalysts for use in polymer electrolyte fuel cells, investigating their activity in methanol oxidation. The evaluated methods were formic acid reduction (FAM), methanol reduction (ARM), and ethylene glycol reduction (ARE). XRD analysis confirmed the formation of a Pt-Ru binary alloy in all syntheses. Electrochemical tests indicated that all catalysts were properly prepared, with the PtRu/CARE catalyst standing out as having the best performance, achieving a power density of 74,88 mW cm−2 at 90°C and an oxygen pressure of 3 atm on the cathode. These results highlight the potential of PtRu/CARE for application in direct methanol fuel cells, surpassing the catalysts obtained through the other methods. [ABSTRACT FROM AUTHOR]

As the core component of proton exchange membrane fuel cells (PEMFCs), the PEM serves as a channel for proton transport and a barrier for electrodes, ensuring efficient energy conversion and the integrity of the cell performance. Metal-organic frameworks (MOFs), with their hybrid organic-inorganic lattices, embody a paradigm of structural and chemical versatility, offering a promising avenue for PEM material innovation. In this work, a phosphorylated MOF (ZnL) synthesized from 1, 1′-piperazinedimethylene phosphate and zinc chloride was integrated into a cytosine-modified SPEEK matrix, yielding advanced composite PEMs. The composite enhanced thermal stability, and mechanical integrity and minimized swelling of the membranes. The incorporation of ZnL improved the proton conductivity, enhanced thermal stability and decreased methanol permeability. The strong interaction between the nucleobase and phosphoric acid in the membrane stabilized the acid, ensuring the membranes' stability and increasing proton conductivity. All PA-doped membranes exhibited satisfactory proton conductivity and mechanical properties. Notably, the SPEEK-C-1ZnL/PA membrane achieved a decomposition temperature of 230 °C and a maximum proton conductivity of 240.34 mS cm−1. During direct methanol fuel cell (DMFC) testing, it demonstrated a power density of 70.67 mW cm−2 and maintained an open circuit voltage of 90.6% after 320 h. These results highlight the potential of this membrane for DMFC applications. This worked developed a cytosine-modified SPEEK matrix integrated with phosphorylated MOFs, achieving enhanced DMFC performance and durability. [Display omitted] • SPEEK-C- x ZnL/PA composites enhanced thermal stability and mechanical properties. • Ionic crosslinking and acid-base pairs in SPEEK-C- x ZnL/PA created efficient proton channels. • The SPEEK-C-1ZnL/PA membrane exhibited excellent proton conductivity. • The SPEEK-C-1ZnL/PA membrane demonstrated high power density and long-term stability in DMFCs. [ABSTRACT FROM AUTHOR]

Ammonia, with high hydrogen content and carbon neutrality, is an ideal fuel for protonic ceramic fuel cells (PCFCs). However, the limited electrochemical efficiency and durability of ammonia‐based PCFCs have posed challenges for broader implementation. Herein, a novel anode material, Ni‐Ba(Zr0.1Ce0.7Y0.1Yb0.1)0.94Ru0.03Fe0.03O3‐δ (BZCYYbRF), developed by co‐doping with Ru and Fe is introduced, which promotes the exsolution of RuFe nanoparticles under reducing conditions. A secondary redox process further enhances nanoparticle redistribution, increasing catalytic activity and improving ammonia decomposition and hydrogen oxidation, as well as the charge transfer at the heterointerface, leading to a marked improvement in the electrochemical performance of the PCFC under both hydrogen and ammonia fuel conditions. A single cell utilizing BZCYYbRF as the anode achieves a peak power density of 700 mW cm⁻2 at 650 °C under NH3 fuel, with stable operation for up to 150 h. Additionally, secondary redox treatment improved performance to 807 mW cm⁻2 at 650 °C. The innovation lies in the co‐doping and redox‐driven nanoparticle exsolution strategy, significantly boosting PCFC performance and stability, positioning this anode as a breakthrough for direct ammonia fuel cells. [ABSTRACT FROM AUTHOR]

The development of a hybrid electrocatalyst with multi-active sites that enhances the efficiency of the anodic reaction in the direct methanol fuel cells (DMFCs), is an important topic. Zeolite imidazole frameworks (ZIFs) and transition metal oxides exhibit promising performance in this regard. Herein, novel nanocomposites of nickel cobaltite (NiCo 2 O 4), carbon nanotubes (CNTs), and ZIF-67-derived Co 3 O 4 rhombic dodecahedron nanoparticles were prepared using the hydrothermal process followed by the pyrolysis method. The electro-catalytic activity and stability of the prepared electrodes toward methanol electro-oxidation were investigated in basic medium. The results show that ZIF-67/CNTs/NiCo 2 O 4 /NF is the most promising nanocomposite for methanol electro-oxidation with a delivered catalytic current density of 160 mA cm−2 at a scan rate of 40 mV‧s−1. The synergistic effect of combining CNTs with NiCo 2 O 4 and ZIF-67 is the reason for the highly electro-catalytic activity of ZIF-67/CNT/NiCo 2 O 4 /NF. This new structure and composition introduce a promising avenue for the development of electrocatalysts for methanol electro-oxidation. [Display omitted] • Novel nanocomposites of nickel cobaltite, CNTs, and ZIF-67-derived Co 3 O 4 were prepared. • The electro-catalytic activity towards methanol electro-oxidation was investigated. • ZIF-67/CNT/NiCo 2 O 4 /NF shows a current density of 160 mA cm−2 at a scan rate of 40 mV‧s−1. • A synergistic effect is the reason for the high catalytic activity of ZIF-67/CNT/NiCo 2 O 4 /NF. [ABSTRACT FROM AUTHOR]

This review focuses on fillers, modifications, and methods used in the preparation and development of sulfonated poly(ether ether ketone) (sPEEK) membranes, specifically for direct methanol fuel cell (DMFC) applications as proton exchange membranes in recent years. The primary objective is to evaluate recent advancements by emphasizing key characteristics such as water uptake and swelling capacity, ionic conductivity, methanol permeability, and single cell polarization tests. Additionally, the review aims to provide insights for future researchers by discussing the preparation processes of electrolytes. It presents basic characterizations of membrane electrolytes, including evaluations of the sulfonation degree and ion exchange capacities of sPEEK. High performance of membrane electrolytes is essential for commercialization and to compete with established membranes like Nafion®, which has a perfluorosulfonic acid structure. Therefore, the review also covers detailed characterization methods for assessing long‐term stability when available in the related studies. Numerical results and indicators are categorized and tabulated for easy interpretation and comparative analysis. [ABSTRACT FROM AUTHOR]

Sche me 2. The Methanol oxidation reaction mechanism in acidic media is shown schematically. [Display omitted] • Carbon nanoboxes (CNB) were prepared using MOF strategy to facilitate their ion and electron transport. • Pt/PProDOT/CNB catalysts with hollow structure, porous weave and nitrogen doped structure advantages. • Pt/PProDOT/CNB and Pt/CNB exhibit excellent catalytic activity, CO tolerance, and long-term stability. • The PProDOT/CNB interface accelerates reaction kinetics. • In situ polymerisation enables PProDOT to modify CNB uniformly. To improve the efficiency of the methanol oxidation reaction (MOR) in direct methanol fuel cells (DMFCs), it is essential to develop catalysts with high catalytic activity. However, constructing polyatomic doped carbon nanomaterials and understanding the interaction mechanisms between dopant elements remain significant challenges. In this study, we propose nitrogen-doped carbon nanobox (CNB) derived from Zeolitic Imidazolate Framework-67 (ZIF-67) crystals as precursors to serve as carriers for highly efficient platinum nanoparticles (Pt NPs). We synthesized platinum/poly(3,4-propylenedioxythiophene)/carbon nanobox (Pt/PProDOT/CNB) composites by wrapping CNB around PProDOT films via in situ oxidative polymerization. This unique structural design provides several advantages to the catalyst, including a large active surface area, numerous accessible electrocatalytic active centers, an optimized electronic structure, and good electronic conductivity. The Pt/PProDOT/CNB composites demonstrated excellent methanol oxidation performance, with a remarkable mass activity (MA) of 1639.9 mA mg-1 Pt and a high electrochemical active surface area (ECSA) of 160.8 m2/g. Furthermore, the catalyst exhibited good CO resistance and outstanding durability. [ABSTRACT FROM AUTHOR]

[Display omitted] Heteroatom-doped carbon materials are widely used to improve the electrocatalytic oxidation of methanol; however, the underlying mechanisms driving this enhancement remain poorly understood. A major challenge lies in developing non-doped carbon supports with tunable intrinsic defect types tailored for metal-based catalysts. In this study, we synthesize a series of ordered mesoporous carbon (OMC) supports with adjustable edge defect densities by varying roasting temperatures and employing a zinc (Zn) evaporation strategy to systematically investigate the impact of edge defects on methanol oxidation reaction (MOR) performance. Theoretical calculations and structural characterizations confirm that the electron metal-support interaction (EMSI) between OMC edge defects and palladium nanoparticles (Pd NPs) effectively modulates the electronic structure of Pd NPs. This modulation not only enhances overall reaction activity and selectivity for the non-CO pathway but also strengthens the anchoring of Pd NPs, leading to superior activity and stability of the Pd/OMC-Zn 0.55 catalyst in methanol electrocatalytic oxidation. Notably, after rigorously excluding the influence of various physicochemical properties of the carbon supports, the crucial role of edge defects in improving MOR performance is established. This work provides essential insights into the controlled synthesis of carbon-based catalysts with edge defects and introduces promising strategies for the development of high-performance anode catalysts for direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

The study focuses on the development and optimization of (Ni 87 Fe 4 Cr 9) 78 Si 8 B 14 amorphous ribbons as self-supported electro-catalysts for oxygen evolution reaction (OER) and methanol oxidation reaction (MOR). Electro-catalytically active nano α-Ni(OH) 2 phase (5–10nm) was generated in the amorphous ribbon surface through potentiostatic cathodic corrosion for different time intervals (0–120 min). The X-ray diffraction and scanning electron microscopy results shows the favourable occurrence of dense nanocrystallization of α-Ni(OH) 2 between 45 and 90 min of corrosion time. For OER in 1 M KOH, the 60-min surface modified ribbon exhibits an overpotential of 295 mV at 10 mA/cm2 current density and tafel slope of 51 mV dec−1. In case of MOR in 1 M KOH +1 M MeOH, the 90-min corroded ribbon shows lowest potential of 1.38 V vs RHE, at 10 mA/cm2 and tafel slope of 34 mV dec−1. In addition to superior electro-catalytic activity, the optimal surface-modified ribbons show superior long-term stability for OER and MOR studies, indicating its potential application in hydrogen generation and direct methanol fuel cell. [Display omitted] • Surface modified amorphous ribbon improves the electrocatalytic OER and MOR. • Catalytically active Nickel oxo/hydroxo sites are formed by Cathodic corrosion. • XPS of Ni2p suggests formation of oxygenated nickel species in corroded ribbon. • Optimized sample shows an overpotential of 295 mV at 10 mA/cm2 for OER. • Low onset in MOR (1.36 V vs RHE) widens its application in DMFC and H 2 generation. [ABSTRACT FROM AUTHOR]

The commercialization process of the direct methanol fuel cell technology is seriously blocked by the insufficient catalytic efficiency and low natural abundance of traditional Pt-based anode catalysts, which motivates the research on the design and synthesis of advanced non-Pt catalysts with high performance and acceptable costs. Herein, we report a controllable and robust building method to the bottom-up preparation of ultrasmall Rh-decorated porous heterostructures stereoassembled from Ti 3 C 2 T x MXene and reduced graphene oxide nanosheets (Rh/MX-RGO) through a facile solvothermal process. The presence of three-dimensional crosslinked graphene aerogel network provides abundant porosity and inhibits the nanosheets from longitudinal restacking, while the introduction of MXene offers extra anchoring sites for the immobilization of Rh nanoparticles as well as ameliorates their electronic structure. Consequently, the resultant Rh/MX-RGO catalyst manifests impressive alkaline methanol oxidation properties, including a large electrochemically active surface area of 91.8 m2 g−1, a high mass (specific) activity of 1605.0 mA mg−1 (1.74 mA cm−2), a small Tafel slope of 89 mV decade−1, strong poison resistance, and reliable long-term stability, all of which significantly outperform those of reference Rh/MXene, Rh/RGO, Rh/carbon nanotube, Rh/carbon black, and widely-used Pt/carbon black and Pd/carbon black catalysts. A controllable and robust building method is developed to the bottom-up synthesis of ultrasmall Rh-decorated porous heterostructures stereoassembled from Ti 3 C 2 T x MXene and graphene, which demonstrate superior electrocatalytic performance toward methanol electrooxidation. [Display omitted] • The bottom-up construction of porous heterostructures stereoassembled from MXene and graphene is achieved. • Well-dispersive Rh nanocrystals are in situ immobilized on crosslinked MXene-graphene frameworks. • The unique architectural design prevents the nanosheet restacking and ameliorates the Rh electronic structure. • The resulting heterostructure expresses excellent catalytic properties toward methanol electrooxidation. [ABSTRACT FROM AUTHOR]

Recently, direct methanol fuel cells (DMFCs) have been regarded as the greatest energy-producing owing to their low operating temperature, high production rate of methanol, and low greenhouse gas emission. However, the energy conversion efficiency of the DMFCs is still unsatisfactory due to the slow kinetics of the fuel oxidation reaction. So, an economic electrocatalyst with high efficiency and good stability is still needed. Herein, low-cost nanocomposites of (Ni/Cu/N) MOF and palm pollen-derived G-graphite were prepared with different ratios namely, (1:1), (1:2), and (2:1) through a solvothermal reaction. The nanocomposites were characterized via X-ray diffraction (XRD), Scanning electron Microscopy (SEM), Fourier transform infrared (FTIR), Thermal gravimetric analysis (TGA), and, (Brunauer–Emmett–Teller) technique (BET). Electrodes have been tested as electro-catalysts for methanol-oxidation reaction (MOR) in a basic medium. As revealed from the cyclic voltammetry measurements, all electrodes exhibit a good response to MOR, being the nanocomposite with the ratio between (Ni/Cu/N) MOF and G-graphite (2:1) is the best with an oxidation peak current density of 55 mA/cm2 at a scan rate of 50 mV/s, with an onset potential of 0.35 V, and stability reaches 96 %. The electrochemical impedance spectroscopy (EIS) test showed that the ratio (2:1) has the lowest charge transfer resistance, R CT , of 5.21 Ω which confirms its higher electrochemical activity. This superior performance of the (Ni/Cu/N) MOF and G-graphite (2:1) over other reported MOF-based electrocatalysts is attributed to the synergistic effect of the (Ni/Cu/N) MOF electrocatalyst, wherein Ni and Cu provide redox electrocatalytic active sites for MOR while the G-graphite contributes towards the chemical stability and electrical conductivity of the electrode, respectively. The good activity and stability of the prepared electrodes suggest the potential use of these electrodes as electrocatalysts for MOR in direct methanol fuel cells (DMFCs).This study opens the venue for valorizing the natural wastes derived graphitic material as stable supporting material in Mof based composites electrodes for MOR. • Green Graphite derived from palm pollen grains was prepared simply. • low-cost nanocomposites of (Ni/Cu/N) MOF pollen-derived G-graphite were prepared. • (Ni/Cu/N) MOF- based nanocomposites prepared with different ratios. • The prepared materials were tested as electro-catalysts for MOR. • Nanocomposite of (Ni/Cu/N) MOF and G-graphite with a ratio (2:1) display superior performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A zwitterion-modified fiber substrate was used to fill with SPEEK to prepare PEM. • Zwitterionic interface provided fast channels for proton transport. • High proton conductivity and chemical stability were obtained. • Better DMFC performance than that of commercial Nafion 212 membrane was obtained. Proton exchange membranes with high ionic conductivity and good chemical stability are critical for achieving high power density and long lifespan of direct methanol cells (DMFCs). Herein, a zwitterionic molecule was grafted onto the surface of polyvinylidene fluoride (PVDF) nanofibers to obtain functionalized PVDF porous substrate (SBMA-PDA@PVDF). Then, sulfonated poly(ether ether ketone) (SPEEK) was filled into the pores of SBMA-PDA@PVDF, and further ionic cross-linked via H 2 SO 4 to prepare the composite membrane (SBMA-PDA@PVDF/SPEEK). The basic groups on the zwitterionic interface could not only establish ionic cross-linking with SPEEK to increase chemical stability and reduce swelling, but also serve as the adsorption sites for subsequent H 2 SO 4 cross-linking to significantly enhance proton conductivity. Super-high proton conductivity (165.34 mS cm−1, 80 °C) was achieved for the membrane, which was 2.12 times higher than that of the pure SPEEK. Moreover, the SBMA-PDA@PVDF/SPEEK membrane exhibited remarkably improved oxidative stability of 91.6 % mass retention after soaking in Fenton's agent for 12 h, while pure SPEEK completely decomposed. Satisfactorily, the DMFC assembled with SBMA-PDA@PVDF/SPEEK exhibited a peak power density of 99.01 mW cm−2, which was twice as much as that of commercial Nafion 212 (48.88 mW cm−2). After 235 h durability test, only 11 % voltage loss was observed. [ABSTRACT FROM AUTHOR]

[Display omitted] Hydrogen peroxide (H 2 O 2) emerges as a viable oxidant for fuel cells, necessitating the development of an efficient and cost-effective electrocatalyst for the hydrogen peroxide reduction reaction (HPRR). In this study, we synthesized a self-supporting, highly active HPRR electrocatalyst comprising two morphologically distinct components: CeO 2 -NiCo 2 O 4 nanowires and CeO 2 -NiCo 2 O 4 metal organic framework derivatives, via a two-step hydrothermal process followed by air calcination. X-ray diffraction and transmission electron microscopy analysis confirmed the presence of CeO 2 and NiCo 2 O 4 , revealing the amalgamated interface between them. CeO 2 exhibits multifunctionality in regulating the surface electronic configuration of NiCo 2 O 4 , fostering synergistic connections, and introducing oxygen deficiencies to enhance the catalytic efficacy in HPRR. Electrochemical measurements demonstrate a reduction current density of 789.9 mA·cm−2 at −0.8 V vs. Ag/AgCl. The assembly of direct borohydride-hydrogen peroxide fuel cell (DBHPFC) exhibits a peak power density of 45.2 mW·cm−2, demonstrating durable stability over a continuous operation period of 120 h. This investigation providing evidence that the fabrication of heterostructured catalysts based on CeO 2 for HPRR is a viable approach for the development of high-efficiency electrocatalysts in fuel cell technology. [ABSTRACT FROM AUTHOR]

Anode catalysts are important for direct methanol fuel cells (DMFCs) of energy conversion. Herein, we report a novel strategy by ethylene glycol-based deep eutectic solvents (EG-DESs) for the fabrication of a multi-walled carbon nanotubes (MWCNTs)-supported Pt nanoparticles catalyst (referred to as Pt/CNTs-EG-DES). The Pt/CNTs-EG-DES catalyst provides an increased electrochemically active surface area (ECSA) and shows remarkably improved electrocatalytic performance towards methanol oxidation reaction compared to Pt/CNTs-W (fabricated in water) and commercial Pt/C catalysts. The improved performance is attributed to the generation of more Pt–O bonds which change the electronic states of the Pt atoms and the special node structure that obtains more active sites for a high CO resistance. This study suggests an effective synthesis strategy for Pt-based electrocatalysts with high performance for DMFC applications. [ABSTRACT FROM AUTHOR]

Low‐volume power density remains a significant barrier to the portable application of direct methanol fuel cell (DMFC). Herein, a shared anode flow field (SAFF) structure is introduced in an active DMFC to reduce stack volume and improve discharge performance. The differences in discharge performance between the bi‐cell with SAFF and the bi‐cell with traditional anode flow field (TAFF), coupled with the effect of operating conditions on performance, are investigated by polarization curve, electrochemical impedance spectra, and voltage versus time curves. The results show that the SAFF structure enhances anode mass transfer, resulting in an improvement in peak power density and voltage stability of the bi‐cell compared to the TAFF structure. In addition, the bi‐cell with SAFF achieves its highest peak power density at a lower methanol concentration, alleviating the methanol crossover caused by high concentration. The SAFF structure is an attractive choice for DMFC portable applications. [ABSTRACT FROM AUTHOR]

Fuel cells are promising fossil fuel alternatives that are both environmentally friendly and powerful. Direct methanol fuel cells are particularly suitable for lightweight cars and portable electronics. Developing efficient, cost-effective, and eco-friendly catalysts for energy storage and conversion devices is vital for long-term energy security. Numerous studies have explored using metal oxides and modifications to mixed transition metal oxide (MTMO)-based catalysts to enhance the methanol oxidation process. Coupling transition metals (Mn, Co, Ni, Fe, Zn, etc.) in MTMOs improves redox processes and electronic conductivity, advancing electrochemical applications. Among these, nickel cobaltite (NiCo₂O₄) stands out due to its material stability and higher electronic conductivity compared to single-component metal oxides NiO and Co₃O₄. NiCo₂O₄ shows great potential as a composite-based material for fuel cell applications. This paper reviews studies on NiCo₂O₄ as composite-based materials for electrocatalysts, including various methods for synthesizing nanostructures suitable for direct methanol fuel cells. It also highlights the challenges and potential benefits of using NiCo₂O₄ in practical energy storage systems, offering valuable perspectives and insights for early-stage researchers focused on future research and development in composite-based materials for energy applications. [ABSTRACT FROM AUTHOR]

Direct formic acid fuel cells have attracted significant attention due to their low fuel crossover, high safety, and high theoretical power density among all proton‐exchange membrane fuel cells. Numerous efforts have been dedicated to studying formic acid oxidation, particularly in the fabrication of high‐performance electrocatalysts with economical utilization of Pt metal. In this work, we report a synthetic strategy to create PtAg dots supported on plate‐like Au nanoparticles and explore their applications in electrocatalytic formic acid oxidation. The highly dispersed nature of the catalytic Pt centers and the successful construction of PtAg−Au trimetallic interfaces makes the current nanostructure an ideal system to allow for a synergetic effect between Pt, Au, and Ag, leading to improved electrocatalysis. Compared with commercial Pt/C, our PtAg‐on‐Au heterogenous nanoplates exhibit superior mass activity, along with enhanced reaction kinetics and long‐term durability for FAOR in an acidic medium. Density functional theory (DFT) simulation results indicate that AgPtAu(111) exhibits a relatively high activity for HCOOH oxidation into CO2 among the various Au‐based catalysts. This work provides a viable strategy for constructing Pt‐based electrocatalysts with controlled Pt ensembles, offering insights into the development of fuel cell catalysts that make highly efficient use of costly noble metals. [ABSTRACT FROM AUTHOR]

Mini passive direct methanol fuel cells (mpDMFCs) appear to be a promising alternative for powering portable devices, since they use a liquid fuel, have a fast refuelling time, have a high efficiency and have a low environmental impact. However, some issues need to be solved before their commercialization, such as methanol crossover, short lifetime and high costs. The present work studies the effect of reducing the anode and cathode catalyst loading on the performance of a mpDMFC towards a reduction in the system costs and the characterization of the system losses. The undesirable losses that affect the fuel cell performance were identified and quantified using the electrochemical impedance spectroscopy (EIS) technique. Accordingly, a novel equivalent electric circuit (EEC) was proposed, accurately reproducing the mini pDMFC. In this work, a maximum power density of 7.07 mW cm−2 was obtained, with a methanol concentration of 5 M, using 2 mg cm−2 Pt-RuB and 4 mg cm−2 PtB. The mpDMFC allowed the cell to work with high methanol concentrations and reduced anode catalyst loadings. [ABSTRACT FROM AUTHOR]

Direct Methanol Fuel Cell (DMFC) is a powerful system for generating electrical energy for various applications. However, there are several limitations that hinder the commercialization of DMFCs, such as the expense of platinum (Pt) at market price, sluggish methanol oxidation reaction (MOR) due to carbon monoxide (CO) formation, and slow electrooxidation kinetics. This work introduces carbon nanocages (CNCs) that were obtained through the pyrolysis of polypyrrole (Ppy) as the carbon source. The CNCs were characterized using BET, XRD, HRTEM, TEM, SEM, and FTIR techniques. The CNCs derived from the Ppy source, pyrolyzed at 750 °C, exhibited the best morphologies with a high specific surface area of 416 m2g−1, allowing for good metal dispersion. Subsequently, PtRu catalyst was doped onto the CNC-Ppy750 support using chemical reduction and microwave-assisted methods. In electrochemical tests, the PtRu/CNC-Ppy750 electrocatalyst demonstrated improved CO tolerance and higher performance in MOR compared to PtRu-supported commercial carbon black (CB), with values of 427 mA mg−1 and 248 mA mg−1, respectively. The superior MOR performance of PtRu/CNC-Ppy750 was attributed to its high surface area of CNC support, uniform dispersion of PtRu catalyst, and small PtRu nanoparticles on the CNC. In DMFC single-cell tests, the PtRu/CNC-Ppy750 exhibited higher performance, approximately 1.7 times higher than PtRu/CB. In conclusion, the PtRu/CNC-PPy750 represents a promising electrocatalyst candidate for MOR and anodic DMFC applications. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Over the past decades, there has been an increase in the awareness of direct methanol fuel cells (DMFCs). This study analysed the research activities on electro-catalysts for DMFCs from 1992 to 2023 using bibliometric analysis. This was achieved by extracting the relevant data from web of science (https://www.webofknowledge.com), and retrieved data were analysed by using the Rstudio software. A total of 1912 documents were recovered from this database. Rstudio outputs were annual scientific production, most productive authors, top manuscripts per citations, corresponding author's countries, total citations per country, most relevant sources, most relevant keywords, and research collaboration index. It was observed from the retrieved data that there is an increase in publications of research on electro-catalysts for direct methanol fuel cells from 1992 to 2020. A huge drop was observed from 2021 to 2023. The data provided a documents per author of 0.408 and authors per document of 2.45. It is observed that collaboration index is 2.48. China, USA, and Korea are the top 3 countries in both total citations and countries with most articles in this field. This study is of great help in informing communities, researchers, policy makers, and industries about the importance of DMFC development in providing alternative power source. [ABSTRACT FROM AUTHOR]

To find a solution to the global energy demand, efficient energy production and storage devices are utmost required. Taking advantage of the unique combination of hydrophilicity and conductivity of MXene, a bifunctional nonnoble metal-based electrode NiCo2O4/NiO/MXene (CNOT) is developed. Low conductivity and aggregation of transition metal oxides are compensated by making a hybrid of NiCo2O4/NiO with MXene. CNOT, as an anode catalyst in direct methanol fuel cell (DMFC), offers methanol oxidation reaction current density of 15A/g and low onset potential. Symmetric supercapacitor developed using CNOT in 3M KOH solution offers 0.9V potential window, and 32.66Fg−1 specific capacitance at 2.5A/g. Whereas, symmetric supercapacitor CNOT//CNOT in PVA/KOH hydrogel polymer electrolyte provides a broader window of 1.4V, with specific capacitance of 87.331Fg−1, and very high energy and power density of 23.77Wh/kg and 1808.87W/kg, respectively, at 2.5A/g. The hydrogel polymer electrolyte (PVA/KOH) outperforms aqueous 3M KOH by providing a larger window, higher capacitance, excellent energy and power density. Thus, the hybrid electrode provides synergistic effects of the electro-active NiCo2O4, NiO and MXene nanosheets and exhibits versatility in DMFC and symmetric supercapacitor. [ABSTRACT FROM AUTHOR]

The development of advanced efficient and durable non-precious metal-based anode catalysts for photo-assisted direct methanol fuel cells remains a significant challenge. In this study, Ce-doped Co3O4 (Ce–Co3O4) was prepared by a three-step process involving hydrothermal synthesis, cation exchange and calcination. The introduction of Ce can not only induce more Co3+ with oxidation properties, but also expand the light absorption range and improve the separation efficiency of photogenerated electron–hole pairs. In an alkaline solution and under visible light irradiation, Ce–Co3O4 showed high current density (31.4 A g−1), high photo-response current (3.52 A g−1) and good long-term stability (the current density retention was 82% after 13 h under visible light irradiation). The reaction mechanism for the photo-assisted methanol oxidation was investigated by a series of optical characterization studies (UV-vis diffuse reflectance spectroscopy, Mott–Schottky, photoluminescence spectroscopy, and electron paramagnetic resonance). The results indicated that the strong oxidative photogenerated hole (h+), ˙OH, and ˙O2− were beneficial for the oxidation of methanol and COads. This study provides a good idea for the design of efficient non-precious metal based anode catalysts for photo-assisted direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) is a critical step for oxygen production during the electrochemical splitting of water. Effective OER catalysts support the development of clean energy technologies by increasing the energy efficiency of these processes. In this study, carbon aerogel (CA) was first synthesized as a catalyst support material using sol-gel, supercritical drying, and pyrolysis process. Then, mono-metallic (Pd/CA, Al/CA), bi-metallic (Pd–Al/CA, Pd–Ni/CA), and tri-metallic (Pd–Ni–Al/CA) catalysts were synthesized by microwave irradiation method. Inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy have been made to examine the structural properties of the synthesized catalysts. Electrochemical analysis was carried out through cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS) in alkaline media (1 M KOH: Methanol) to examine the effect of metal loading of CA support material towards OER performance. All the compositions showed excellent activity toward OER, among all Pd–Ni/CA catalysts showed the highest activity. The OER peak current increased remarkably up to 48 mA cm−2 with methanol addition, which signifies the substantial application of carbon aerogel supported-Pd-Ni-Al catalysts in direct methanol fuel cells (DMFCs). Pd–Ni/CA display high OER performance with maximum diffusion coefficient, Do (6.6 × 10−8 cm2 s−1) and heterogeneous rate constant, ko (4.706 × 10−4 cm s−1), and smaller value of Tafel slope (128 mV dec−1). Electrochemical studies predicted that all the prepared carbon aerogel supported-Pd-Ni-Al catalysts can be used as efficient catalysts for OER and other related electrocatalysis applications. • Carbon aerogel (CA) supported Pd–Ni–Al based catalysts were synthesized. • Microwave irradiation method was used as catalyst preparation method. • Mono-metallic (Pd/CA, Al/CA), bi-metallic (Pd–Al/CA, Pd–Ni/CA) and tri-metallic (Pd–Ni–Al/CA) catalysts were synthesized. • Carbon aerogel supported Pd–Ni–Al catalysts can be used as efficient catalyst for OER. [ABSTRACT FROM AUTHOR]

In this work, an anode current collector with a scaled step-hole structure (called SF-type) and a cathode current collector with a perforated cross-tilt structure (called X-type) were designed and fabricated for application in passive direct methanol fuel cells (DMFCs). A whole-cell test showed that the combination of an anode SF-type current collector and cathode conventional current collector increased the optimal methanol concentration from 6 M to 8 M and the maximum power density to 5.40 mW cm−2, which improved the cell performance by 51.6% compared to that of the conventional design under ambient testing conditions. The combination of the anode conventional current collector and cathode X-type current collector achieved a maximum power density of 5.65 mW cm−2 with a 58.7% performance improvement, while the optimal methanol concentration was increased to 10 M. Furthermore, the combination of anode SF-type and cathode X-type obtained the highest power density at 6.22 mW cm−2. Notably, the anode and cathode catalyst loadings used in this study were 2.0 mg cm−2, which is lower than the commonly used loading, thus reducing the fuel cell cost. [ABSTRACT FROM AUTHOR]

In this work, a poly (vinylidene fluoride) (PVDF) and cellulose acetate (CA) blend membrane is developed using the solution casting method for a direct methanol fuel cell (DMFC). The CA addition in PVDF polymer reduces the dense structure of the polymer and creates a porous surface by increasing the amorphous region that is confirmed by surface morphology and crystallinity examination tests. The high glass transition temperature of CA boosts the protection from the melting of PVDF membrane and increases the thermal shrinkage that reduces the probability of a short circuit. PVDF and CA with abundant hydroxyl groups and carboxylic groups enhance the water uptake, also the hydrogen bonding in between them promotes the mechanical strength and develops a tortuous structure that allows protons to pass through them and block the methanol crossover. The 60% PVDF and 40% CA blend membrane shows an ion exchange capacity value of 0.91 and a methanol permeability value of 4.21 × 10–7 cm2 s−1, which is lower than that of the conventional Nafion 117 membrane (19.5 × 10–7 cm2 s−1). A direct methanol fuel cell with this membrane represents a power density value of 16.5 mW cm−2 with a voltage and current density values of 0.178 V and 165 mA cm−2 at 1 M methanol concentration and room temperature. Moreover, it shows a 70% voltage retention after 20 h of testing of the cell at room temperature that is superior to that of the commercial Nafion 117 membrane (48% voltage retention). [ABSTRACT FROM AUTHOR]

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]

Metal-organic frameworks are beginning to be employed in the thermal management system of lithium-ion batteries because of its high water absorption and enthalpy of phase change. However, its cooling performance is only preliminarily explored used in small cylindrical cells or a single large cell. The effect on multiple large-capacity cells has not be verified yet. In this study, a micro heat pipe arrays@ MIL-101(Cr) hybrid battery thermal management system is proposed, and its cooling performance of different number of battery modules at different discharge rates is studied. Experimental results show that MIL-101(Cr) is evenly distributed, and the water vapor adsorption capacity reached 1.65 g/g. The maximum temperature of the micro heat pipe arrays@MIL-101(Cr) group was 36.42 °C in the experiment of the four-cell battery pack at 1C discharge rate, which was 12.98 °C lower than that of the natural cooling group and 3.05 °C lower than that of the micro heat pipe arrays group. With the increase of the number of cells, the maximum temperature of the battery pack rises from 43.12-47.37 °C, and the temperature difference rises from 1.53-5.57 °C at 2C discharge rate. As the discharge rate increases, the maximum temperature of the battery consisting of four cells rises from 36.42-47.37 °C, and the maximum temperature difference rises from 2.87-5.57 °C, which suggests that the current micro heat pipe arrays@MOF based battery thermal management system be combined with an active thermal management system to ensure temperature control in high rate and multi-battery modules. [ABSTRACT FROM AUTHOR]

Four non-fluorinated sulfonimide polyamides (s-PAs) were successfully synthesized and a series of membranes were prepared by blending s-PA with polyvinylidene fluoride (PVDF) to achieve high-methanol-permeation resistivity for direct methanol fuel cell (DMFC) applications. Four membranes were fabricated by blending 50 wt% PVDF with s-PA, named BPD-101, BPD-102, BPD-111 and BPD-211, respectively. The s-PA/PVDF membranes exhibit high methanol resistivity, especially for the BPD-111 membrane with methanol resistivity of 8.13 × 10−7 cm2/s, which is one order of magnitude smaller than that of the Nafion 117 membrane. The tensile strength of the BPD-111 membrane is 15 MPa, comparable to that of the Nafion 117 membrane. Moreover, the four membranes also show good thermal stability up to 230 °C. The BPD-x membrane exhibits good oxidative stability, and the measured residual weights of the BPD-111 membrane are 97% and 93% after treating in Fenton's reagent (80 °C) for 1 h and 24 h, respectively. By considering the mechanical, thermal and dimensional properties, the polyamide proton-exchange membrane exhibits promising application potential for direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Applied Chemistry (JAC) is the property of Semnan University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work presents a comparative study of three synthesis methods for PtRu/C catalysts for use in polymer electrolyte fuel cells, investigating their activity in methanol oxidation. The evaluated methods were formic acid reduction (FAM), methanol reduction (ARM), and ethylene glycol reduction (ARE). XRD analysis confirmed the formation of a Pt-Ru binary alloy in all syntheses. Electrochemical tests indicated that all catalysts were properly prepared, with the PtRu/CARE catalyst standing out as having the best performance, achieving a power density of 74,88 mW cm−2 at 90°C and an oxygen pressure of 3 atm on the cathode. These results highlight the potential of PtRu/CARE for application in direct methanol fuel cells, surpassing the catalysts obtained through the other methods.