This work aims at the effects of anion-exchange membranes (AEMs) and ionomer binders on the catalyst electrodes for anion-exchange membrane fuel cells (AEMFCs). In the experiments, four metal catalysts (nano-grade Pt, PtRu, PdNi and Ag), four AEMs (aQAPS-S8, AT-1, X37-50T and X37-50RT) and two alkaline ionomers (aQAPS-S14 and XB-7) were used. They were verified through several technical parameters examination and cell performance comparison for the optimal selection of AMEs. The bimetallic PdNi nanoparticles (PdNi/C) loaded with Vulcan XC-72R carbon black were used as anode electrodes by using the wet impregnation method, and Ag nanoparticles (Ag/C) were used as the catalyst cathode. It was found that the power density and current density of the X37-50RT are higher than the other three membranes. Also, alkaline ionomers of XB-7 had better performance than aQAPS-S14. The efficiency was improved by 32%, 155% and 27%, respectively, when compared to other membranes by using the same catalyst of PdNi/C, Ag/C and Pt/C. The results are consistent with the membrane ion conductivity measurements, which showed that the conductivity of the X37-50RT membrane is the highest among them. The conductivity values for hydroxide ions (OH⁻) and bromide ions (Br⁻) are 131 mS/cm and 91 mS/cm, respectively. These findings suggest that the properties (water uptake, swelling rate and mechanical) of the anion-exchange membrane (AEM) can serve as a key reference for AEM fuel cell applications.

This work shows that electrolyte current-density as an indicator can assist in the optimized timing of the addition of the electrolyte to plasma electrolytic polishing (PEP) to keep it active and in operation. In this experiment, 2 wt% ammonium sulfate was used as an electrolyte to polish 1 cm × 1 cm stainless steel SUS304. The hot-bath heating method was successfully used to heat it from 60 to 90 °C, followed by suction filtration. The cathode was fixed at the beaker edge in the electrolyte and the input voltage was 340 volts. Once the gas-phase layer formed stably around the workpiece, the plasma went through the electrolyte to polish the workpiece surface. Then, the anode was slowly immersed into the electrolyte and the current-density measured. It was found that based on the current-density–temperature curve, for the timing of the addition of the electrolyte, the current-density difference could be used to decide whether it needed to be supplemented or not. When the temperature was from 75 to 80 °C and 85 to 90 °C, it was found that the 2 wt% ammonium sulfate solution should be supplemented. The result showed that the electrolyte life indicator, using the current-density, is a feasible method of practical technology for PEP.

Anion exchange membrane fuel cells (AEMFCs) are the most feasible choice of catalyst due to their high efficiency and scale of commercialization. However, the challenge posed by the sluggish kinetics of AEMFCs can only be countered by an effective electrocatalyst that enhances the reaction kinetics and, thereby, the fuel cell performance. The Pd-Co/C cathode catalyst is a promising choice of electrocatalyst, with the phenomenon of alloying playing a key role at appropriate temperatures and residence time distributions of annealing due to the influence of the lattice parameter, electrochemically active surface area (ECSA), and particle size. After completing the synthesis of 20 wt.% Pd-Co/C, the catalyst was treated under various annealing and loading conditions. This was subsequently followed by a series of physicochemical and electrochemical characterizations that verified the successful synthesis of the catalyst material, paving a path to optimizing the annealing temperature, annealing residence time, and catalyst loading. Further, proceeding with the fuel cell test runs with multiple profiles of the above parameters resulted in the optimization of the annealing temperature, residence time of annealing, and catalyst loading, and it was subsequently concluded that the best performance of the fuel cell was achieved when the Pd-Co/C catalyst was annealed at 500 °C for a duration of 1 h and loaded at 0.25 mg/cm², which resulted in an impeccable power density of 724 mW/cm².

This investigation addresses the enhancement of ammonia fuel cell performance using Pd (palladium)- and Co (cobalt)-doped cathode catalysts. Initially, the performance of the Ag/C cathode catalyst in ammonia fuel cells yielded a baseline power density of only 38 mW/cm². To improve efficiency, Pd and Co were introduced, resulting in the synthesis of a new 15 wt% PdAgCo/C (15 wt% PdAgCo and 85 wt% C) cathode catalyst, which increased the power density to 74 mW/cm². Further performance enhancement was achieved by using a highly efficient 40 wt% PtIr/C anode catalyst, as reported in the literature, and applying a cathode catalyst loading of 0.5 mg/cm², raising the power density to 172 mW/cm². This investigation addresses the successful synthesis of a 15 wt% PdAgCo/C cathode catalyst, which has proven to be a better choice over conventional catalysts, along with the significance of doping Pd and Co with Ag/C in the augmentation of catalytic activity and fuel cell performance. Thus, a series of physicochemical and electrochemical characterizations, the approach for optimization of the working parameters, and the impact analysis of catalyst loading have all resulted in the achievement of an impeccable power density of 332 mW/cm².

This study investigated the modification of nanosilver (Ag) by Co-Pc (phthal–cyanine) and the synergistic effect of Ag-Co/CNT (carbon nanotube) for the long-term stability of AEMFCs (anion exchange membrane fuel cells). This study also aimed to use non-precious metal catalysts on both the cathode and anode to reduce the catalyst costs. Through a simple and efficient chemical synthesis method, a composite catalyst consisting of Co-Pc-modified Ag/CNT was successfully prepared and characterized for its structure and composition. Co-Pc and Ag were chosen for their high durability and catalytic activity in fuel cells, combined with a multi-wall carbon nanotube (MWCNT) as a carrier for the cathode catalyst, and the anode catalyst used Pd-CeO₂/C. The performance of the cell module was tested based on a commercial anion exchange membrane (X37-50RT). The experiment focused on different synthesis times and ratios of catalyst and ionomer, observing the enhancement in Co on the active sites of Ag/CNT. Finally, the cell performance was tested for the optimal loading amount. It was observed that when the loading of the nanosilver–cobalt/carbon nanotube (Ag-Co/CNT) is 1 mg/cm², the highest power density is 434.1 mW/cm². Through 100 cycles of testing, only an 18% decrease was observed, while the decrease in open circuit voltage was approximately 4.6%. Compared to nanosilver (Ag/CNT), the Co-Pc-modified nano-Ag with the degradation rate has significantly slowed down, and its catalytic activity has also improved significantly. The enhanced stability of this synergistic effect is mainly attributed to the introduction of cobalt metal, which prevents excessive fusion of nano-Ag particles and surface oxidation, effectively maintaining durability in catalytic activity.