The availability of durable, high-performance electrocatalysts for the hydrogen oxidation reaction (HOR) is currently a constraint for anion-exchange membrane fuel cells (AEMFCs). Herein, a rapid microwave-assisted synthesis method is used to develop a core–shell catalyst support based on a hydrogenated TiO2/carbon for PtRu nanoparticles (NPs). The hydrogenated TiO2 provides a strong metal-support interaction with the PtRu NPs, which improves the catalyst's oxophilicity and HOR activity compared to commercial PtRu/C and enables greater size control of the catalyst NPs. The as-synthesized PtRu/TiO2/C-400 electrocatalyst exhibits respectable performance in an AEMFC operated at 80 °C, yielding the highest current density (up to 3× higher) within
An ultrathin amine-rich selective layer comprising the fixed-site carrier from polyvinylamine (PVAm) and the mobile carrier with an amino acid salt was successfully coated on top of the polysulfone (PSf) substrate for enhanced CO2-facilitated transport. PVAm with an ultrahigh molecular weight was synthesized via the inverse emulsion polymerization method, which allows the excellent dissipation of the reaction heat and reduces gel formation drastically. Several batches of PVAm with different hydrolysis degrees and molecular weights were successfully synthesized. The mobile carriers of 2-(1-piperazinyl)ethylamine salts of sarcosine (PZEA-Sar) were synthesized and introduced to strengthen the facilitated transport contribution, while cellulose nanocrystals (CNCs)
Despite the recent progress in increasing the power generation of Anion-exchange membrane fuel cells (AEMFCs), their durability is still far lower than that of Proton exchange membrane fuel cells (PEMFCs). Using the complementary techniques of X-ray micro-computed tomography (CT), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) spectroscopy, we have identified Pt ion migration as an important factor to explain the decay in performance of AEMFCs. In alkaline media Pt+2 ions are easily formed which then either undergo dissolution into the carbon support or migrate to the membrane. In contrast to PEMFCs, where hydrogen cross over reduces the ions forming
Considering the worldwide efforts for designing catalysts that are not based on platinum group metals while still reserving the many advantages thereof, this study focused on the many variables that dictate the performance of cathodes used for fuel cells, regarding the efficient and selective reduction of oxygen to water. This was done by investigating two kinds of porous carbon electrodes, modified by molecular cobalt(III) complexes chelated by corroles that differ very much in size and electron-withdrawing capability. Examination of the electronic effect uncovered shifts in the CoII/CoIII redox potentials and also large differences in the affinity of the cobalt center to
The existing gap in the ability to quantify the impacts of resistive losses on the performance of anion-exchange membrane fuel cells (AEMFCs) during the lifetime of their operation is a serious concern for the technology. In this paper, we analyzed the ohmic region of an operating AEMFC fed with pure oxygen followed by CO2-free air at various operating currents, using a combination of electrochemical impedance spectroscopy (EIS) and a novel technique called impedance spectroscopy genetic programming (ISGP). Presented here for the first time in this work, we isolated and quantified the individual effective resistance (Reff) values occurring in the AEMFC
Fuel cell deployable anion exchange membranes (AEMs) constitute some of the cleanest and most affordable electrochemical devices. Elucidation of key design principles underlying these electrolytes requires a fundamental understanding of the effect of different cationic functional groups (FGs) on the performance of an AEM. In this study, we use fully atomistic ab initio molecular dynamics simulations to study the effect of the trimethyl alkyl ammonium (TMA) and imidazolium (IMI) FGs on the hydroxide ions and water diffusivity in AEMs under low hydration conditions using nano-confined structures. The IMI FG was found to be a better chaotropic ion, resulting in a higher water diffusivity.
Computer-aided data acquisition, analysis, and interpretation are rapidly gaining traction in numerous facets of research. One of the subsets of this field, image processing, is most often implemented for post-processing material microstructural characterization data to understand better and predict materials' features, properties, and behaviors at multiple scales. However, to tackle the ambiguity of multi-component materials analysis, spectral data can be used in combination with image processing. The current study introduces a novel Python-based image and data processing method for in-depth analysis of energy dispersive spectroscopy (EDS) elemental maps to analyze multi-component agglomerate size distribution, the average area of each component,
Covalent organic framework nanosheets (COF-NSs) are emerging building blocks for functional materials, and
their scalable fabrication is highly desirable. Current synthetic methods suffer from low volume yields resulting from
confined on-surface/at-interface growth space and complex multiple-phase synthesis systems. Herein, we report the
synthesis of charged COF-NSs in open space using a single-phase organic solution system, achieving magnitudes higher
volume yields of up to 18.7 mgmL 1. Charge-induced electrostatic repulsion forces enable in-plane anisotropic secondary
growth from initial discrete and disordered polymers into large and crystalline COF-NSs. The charged COF-NS colloidal
suspensions are cast into thin and compact proton exchange membranes (PEMs) with lamellar morphology and oriented
crystallinity,
Anion exchange membrane fuel cells (AEMFCs) have been regarded as a promising low-cost alternative to proton exchange membrane fuel cells (PEMFCs) due to their potential to utilize platinum group metal (PGM) free catalysts and their recently demonstrated improvement in power density. However, the development of highly active and stable PGM-free electrocatalysts for the hydrogen oxidation reaction (HOR) in alkaline solutions remains a significant challenge. In this study, reactive spray deposition technology (RSDT) is used to fabricate a set of Ni/CeO2/C catalysts, and their activity toward the HOR is investigated as a function of the nanoparticle size. The structural and morphological characterization of as synthesized Ni/CeO2/C catalysts confirms that the RSDT is capable of
The alkaline operating environment of anion-exchange membrane (AEM) fuel cells (AEMFCs) makes it possible to employ a wide variety of catalysts, including platinum group metals (PGMs) as well as PGM-free materials. However, little is understood about radical formation during AEMFC operation with different catalysts and their implications. In this investigation, we utilized spin-trapping and electron-paramagnetic resonance measurements to measure and identify the radicals produced on selected PGM and PGM-free oxygen-reduction reaction catalysts. To the best of our knowledge, this is an original study exploring radical formation on different classes of catalysts in operando AEMFCs. This work highlights an unexplored radical
