Journal of Hydrogen, Fuel Cell and Energy Storage
Volume:10 Issue: 2, Spring 2023

This study explored the impact of solvent dielectric constant on the catalyst layer of proton exchange membrane fuel cell (PEMFC) cathodes during the oxygen reduction reaction. Electrochemical analyses were conducted at 25ºC in 2.0 M H2SO4 on electrodes that had been prepared with the same Nafion and Pt loadings, but different solvent dielectric constants for ink preparation of the catalyst layer. A Nafion loading of 0.5 mg cm-2 and Pt loading of 1 mg cm-2 were employed for all electrodes. The findings of the research revealed that the dielectric constant of the ink utilized for preparing the gas diffusion electrode reaction layer has an impact on the electrode's performance for the oxygen reduction reaction. This effect was evident in both the kinetics parameters linked to the oxygen reduction reaction and the physical characteristics of the electrode surface. In the preparation of the reaction layer, an optimal electrode performance result of 4.2 was achieved in relation to the dielectric constant.

This study aimed to explore new insights within the realm of hybrid renewable energy systems specifically designed for off-grid applications, using a combination of numerical simulations and real-world experiments. The system described in the study was developed to cater to the electricity needs of a telecommunications tower. It was achieved by integrating various components, including a photovoltaic (PV) unit, a proton exchange membrane electrolyzer (PEME), a proton exchange membrane fuel cell (PEMFC), and a battery storage unit. Additionally, an Organic Rankine Cycle (ORC) system is integrated to efficiently capture and utilize waste heat generated by the PEMFC. In this setup, the PV unit serves as the primary source of power, with any excess solar energy being directed towards the PEME during periods of high solar irradiation. The PEME then converts this surplus energy into hydrogen and oxygen. Subsequently, the PEMFC utilizes the stored hydrogen, which is stored in metal hydride tanks, to generate electricity, thus ensuring a continuous and reliable power supply for the telecom tower. Results indicate that an optimal ORC turbine inlet pressure of approximately 600 kPa maximizes overall exergy and energy efficiencies, with 53.2% and 50.9% respectively.

In the near future, hydrogen is expected to become a significant fuel that will largely contribute to the quality of atmospheric air. Hydrogen global production has so far been dominated by fossil fuels. Pure hydrogen is also produced by electrolysis of water, an energy demanding process. In this study a novel multigeneration system is introduced using nanofluid in the solar system. The proposed system includes a quadruple effect absorption refrigeration cycle, a thermoelectric generator, a PEM electrolyzer, vapor generator and domestic water heater. A parametric study is accomplished to consider the effect of significant parameters on the efficiency of the system. It is observed that the power generated by the system is 18.78 kW and the collector energy and exergy efficiency are 82.21% and 80.48%, respectively. Furthermore, the results showed that the highest exergy destruction rate occurs in the solar system at the rate of 4461 kW. The energy and exergy COPs of the absorption chiller are discovered to be 1.527 and 0.936, respectively. The amount of hydrogen production rate decreases by increasing the volume concentration of the nanoparticles, the solar radiation and the figure of merit index.

The development of microelectronic devices has increased the need for a power supply with high power density for long-term operation. In this article, firstly, the microfluidic fuel cells (MFCs) have been introduced, secondly, due to the significant effect of mass transfer on their performance, mass transfer in these fuel cells has been investigated. MFCs have small dimensions and simple geometry, and usually, formic acid and oxygen dissolved in sulfuric acid are used as fuel and oxidizers, respectively. To model the MFC, the equations of continuity, momentum, and mass transfer have been solved in three-dimensional by Open-Foam open-source software and validated with the results available in the references. From Fick's equation has been used to calculate rate of diffusion and from the Butler-Volmer equation has been used to calculate rates of electrochemical reactions in catalyst layers. Preliminary results indicate that the performance of this fuel cell is greatly limited by poor fuel utilization, which is consistent with the experimental data. The flow is fully developed in this short distance from the inlet, and in the fully developed area, the ratio u_max⁄u ̅ is equal 2.1. The mixing zone located at the interface of fuel and oxidizer is in the shape of an hourglass in cross-section, and with increasing the inlet velocity, its thickness decreases along the channel. Also, as the flow moves along the channel, the thickness of the layer with a low concentration near the electrodes increases.

The electrochemical performances derived from the supercapacitors extremely depend on their morphology. So, designing nanostructured electrode materials has a dramatic role in supercapacitors. Herein, highly ordered nanoporous Ni(OH)2 nanobelt arrays (HONNA) were synthesized via a mild wet-chemical route. Ammonia and persulfate concentrations played an important role in the formation of the nanobelt array architecture. The as-prepared nanobelt arrays were characterized using FE-SEM, FT-IR, XRD, and EDX analysis. The resultant Ni(OH)2 nanobelt electrode revealed a specific capacitance of 384 mF cm 2 at 1.0 mA cm 2, fast rate performance, and excellent cycle life. These notable electrochemical features were related to the morphology of highly ordered nanoporous nanobelt array architectures, which provides numerous free channels and offers more electroactive sites and sufficient buffering space to moderate inner mechanical stress and minimize the ion transfer path during the redox reactions. These highly ordered nanoporous Ni(OH)2 nanobelt arrays were suitable candidates as electrode material in supercapacitors.

Along with simulation and data processing tools, computer-aided manufacturing technologies have changed the design and manufacturing methods of functional parts. However, the emerging field of fuel cells and catalytic technology in chemical engineering is also of great interest. In addition to expanding the capabilities of 3D printing, the graceful transfer of digital data and physical parts in these manufacturing methods will be beneficial to research in the design of reactors and structured catalysts, as well as micro fuel cells. Additive manufacturing combines theory and experiment by enabling the design of optimized geometries using computational fluid dynamics. Considering computational modeling and 3D printing as digital tools, this article addresses the design and construction of new structured reactors and fuel cells and also explores the fabrication of micro and solid oxide fuel cells using Additive Manufacturing (AM) and Digital Light Processing (DLP). In this article, we discuss how digital fabrication and computational modeling are intertwined in the field of manufacturing engineering, materials science and chemistry.