Materials

Editorial

Jump to: Research, Review

4 pages, 184 KiB

Open AccessEditorial

Special Issue “Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications”

by Rolando Pedicini

Materials 2022, 15(2), 423; https://doi.org/10.3390/ma15020423 - 6 Jan 2022

Viewed by 1246

Abstract

Hydrogen is a green energy vector that is considered to be one of the most promising fuels for the future [...] Full article

(This article belongs to the Special Issue Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications)

Research

Jump to: Editorial, Review

12 pages, 2246 KiB

Open AccessArticle

A Process for Hydrogen Production from the Catalytic Decomposition of Formic Acid over Iridium—Palladium Nanoparticles

by Hamed M. Alshammari, Mohammad Hayal Alotaibi, Obaid F. Aldosari, Abdulellah S. Alsolami, Nuha A. Alotaibi, Yahya A. Alzahrani, Mosaed S. Alhumaimess, Raja L. Alotaibi and Gamal A. El-Hiti

Materials 2021, 14(12), 3258; https://doi.org/10.3390/ma14123258 - 12 Jun 2021

Cited by 4 | Viewed by 2359

Abstract

The present study investigates a process for the selective production of hydrogen from the catalytic decomposition of formic acid in the presence of iridium and iridium–palladium nanoparticles under various conditions. It was found that a loading of 1 wt.% of 2% palladium in [...] Read more.

The present study investigates a process for the selective production of hydrogen from the catalytic decomposition of formic acid in the presence of iridium and iridium–palladium nanoparticles under various conditions. It was found that a loading of 1 wt.% of 2% palladium in the presence of 1% iridium over activated charcoal led to a 43% conversion of formic acid to hydrogen at room temperature after 4 h. Increasing the temperature to 60 °C led to further decomposition and an improvement in conversion yield to 63%. Dilution of formic acid from 0.5 to 0.2 M improved the decomposition, reaching conversion to 81%. The reported process could potentially be used in commercial applications. Full article

(This article belongs to the Special Issue Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications)

► Show Figures

Figure 1

15 pages, 3788 KiB

Open AccessFeature PaperArticle

Insight towards Nucleation Mechanism and Change in Morphology for Nanostructured Platinum Thin Film Directly Grown on Carbon Substrate via Electrochemical Deposition

by Prabhakaran Dhanasekaran, Swaminathan Rajavarman, Sivasuriyanarayanan Vinod Selvaganesh and Santoshkumar Dattatray Bhat

Materials 2021, 14(9), 2330; https://doi.org/10.3390/ma14092330 - 30 Apr 2021

Cited by 8 | Viewed by 2277

Abstract

Nanocrystalline platinum with different morphologies is synthesized via electrochemical deposition technique. The nucleation mechanism and its structural effect over the electrodeposited Pt on carbon electrodes have been systematically studied. Powder X-ray diffraction, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy are employed to [...] Read more.

Nanocrystalline platinum with different morphologies is synthesized via electrochemical deposition technique. The nucleation mechanism and its structural effect over the electrodeposited Pt on carbon electrodes have been systematically studied. Powder X-ray diffraction, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy are employed to study nucleation, oxidation states, and Pt structure growth on a carbon electrode. This study reports significant development of Pt metal nanoparticles with different morphologies such as a sphere, flower, core-flower, and rod-like structure directly fabricated on carbon electrode while tuning the deposition parameters such as current density, time, temperature, pH during the deposition process. The proposed electrochemical route represents a superior fabrication procedure for large-scale electrode fabrication compared to a conventional method for preparing membrane electrode assemblies for fuel cell stacks. Full article

(This article belongs to the Special Issue Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications)

► Show Figures

Figure 1

20 pages, 10045 KiB

Open AccessArticle

Hydrophilic Cross-Linked Aliphatic Hydrocarbon Diblock Copolymer as Proton Exchange Membrane for Fuel Cells

by David Julius, Jim Yang Lee and Liang Hong

Materials 2021, 14(7), 1617; https://doi.org/10.3390/ma14071617 - 26 Mar 2021

Cited by 5 | Viewed by 2067

Abstract

This study proposes a hydrophobic and hydrophilic aliphatic diblock copolymer wherein the hydrophobic block contains glycidyl methacrylate (GMA) units that are distanced by poly(acrylonitrile) (PAN) segments to fabricate a proton exchange membrane (PEM). This diblock copolymer also known as ionomer due to the [...] Read more.

This study proposes a hydrophobic and hydrophilic aliphatic diblock copolymer wherein the hydrophobic block contains glycidyl methacrylate (GMA) units that are distanced by poly(acrylonitrile) (PAN) segments to fabricate a proton exchange membrane (PEM). This diblock copolymer also known as ionomer due to the hydrophilic block comprising 3-sulfopropyl methacrylate potassium salt (SPM) block. The diblock copolymer was synthesized in the one-pot atom transfer radical polymerization (ATRP) synthesis. Subsequently, the membrane was fabricated by means of solution casting in which an organic diamine, e.g., ethylene diamine (EDA), was introduced to crosslink the diblock copolymer chains via the addition of amine to the epoxide group of GMA. As a result, the PEM attained possesses dual continuous phases, in which the hydrophobic domains are either agglomerated or bridged by the EDA-derived crosslinks, whereas the hydrophilic domains constitute the primary proton conducting channels. The in-situ crosslinking hydrophobic block by using a hydrophilic cross-linker represents the merit aspect since it leads to both improved proton conductivity and dimensional stability in alcohol fuel. To characterize the above properties, Nafion^® 117 and random copolymer of P(AN-co-GMA-co-SPM) were used as control samples. The PEM with the optimized composition demonstrates slightly better fuel cell performance than Nafion 117. Lastly, this diblock ionomer is nonfluorinated and hence favors lowering down both material and environmental costs. Full article

(This article belongs to the Special Issue Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications)

► Show Figures

Figure 1

16 pages, 4317 KiB

Open AccessArticle

Effects of the Chemical Treatment on the Physical-Chemical and Electrochemical Properties of the Commercial Nafion™ NR212 Membrane

by Enza Passalacqua, Rolando Pedicini, Alessandra Carbone, Irene Gatto, Fabio Matera, Assunta Patti and Ada Saccà

Materials 2020, 13(22), 5254; https://doi.org/10.3390/ma13225254 - 20 Nov 2020

Cited by 14 | Viewed by 1938

Abstract

Polymer Electrolyte Fuel Cells (PEFCs) are one of the most promising power generation systems. The main component of a PEFC is the proton exchange membrane (PEM), object of intense research to improve the efficiency of the cell. The most commonly and commercially successful [...] Read more.

Polymer Electrolyte Fuel Cells (PEFCs) are one of the most promising power generation systems. The main component of a PEFC is the proton exchange membrane (PEM), object of intense research to improve the efficiency of the cell. The most commonly and commercially successful used PEMs are Nafion™ perfluorosulfonic acid (PFSA) membranes, taken as a reference for the development of innovative and alternative membranes. Usually, these membranes undergo different pre-treatments to enhance their characteristics. With the aim of understanding the utility and the effects of such pre-treatments, in this study, a commercial Nafion™ NR212 membrane was subjected to two different chemical pre-treatments, before usage. HNO₃ or H₂O₂ were selected as chemical agents because the most widely used ones in the procedure protocols in order to prepare the membrane in a well-defined reference state. The pre-treated membranes properties were compared to an untreated membrane, used as-received. The investigation has showed that the pre-treatments enhance the hydrophilicity and increase the water molecules coordinated to the sulphonic groups in the membrane structure, on the other hand the swelling of the membranes also increases. As a consequence, the untreated membrane shows a better mechanical resistance, a good electrochemical performance and durability in fuel cell operations, orienting toward the use of the NR212 membrane without any chemical pre-treatment. Full article

(This article belongs to the Special Issue Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications)

► Show Figures

Figure 1

27 pages, 6078 KiB

Open AccessArticle

Ionic Transport Properties of P₂O₅-SiO₂ Glassy Protonic Composites Doped with Polymer and Inorganic Titanium-based Fillers

by Maciej Siekierski, Maja Mroczkowska-Szerszeń, Rafał Letmanowski, Dariusz Zabost, Michał Piszcz, Lidia Dudek, Michał M. Struzik, Magdalena Winkowska-Struzik, Renata Cicha-Szot and Magdalena Dudek

Materials 2020, 13(13), 3004; https://doi.org/10.3390/ma13133004 - 6 Jul 2020

Cited by 4 | Viewed by 2092

Abstract

This paper is focused on the determination of the physicochemical properties of a composite inorganic–organic modified membrane. The electrical conductivity of a family of glassy protonic electrolytes defined by the general formula (P₂O₅)_x(SiO₂)_y, [...] Read more.

This paper is focused on the determination of the physicochemical properties of a composite inorganic–organic modified membrane. The electrical conductivity of a family of glassy protonic electrolytes defined by the general formula (P₂O₅)_x(SiO₂)_y, where x/y is 3/7 are studied by Alternating Current electrochemical impedance spectroscopy (AC EIS) method. The reference glass was doped with polymeric additives—poly(ethylene oxide) (PEO) and poly(vinyl alcohol) (PVA), and additionally with a titanium-oxide-based filler. Special attention was paid to determination of the transport properties of the materials thus modified in relation to the charge transfer phenomena occurring within them. The electrical conductivities of the ‘dry’ material ranged from 10⁻⁴ to 10⁻⁹ S/cm, whereas for ‘wet’ samples the values were ~10⁻³ S/cm. The additives also modified the pore space of the samples. The pore distribution and specific surface of the modified glassy systems exhibited variation with changes in electrolyte chemical composition. The mechanical properties of the samples were also examined. The Young’s modulus and Poisson’s ratio were determined by the continuous wave technique (CWT). Based on analysis of the dispersion of the dielectric losses, it was found that the composite samples exhibit mixed-type proton mobility with contributions related to both the bulk of the material and the surface of the pore space. Full article

(This article belongs to the Special Issue Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications)

► Show Figures

Figure 1

13 pages, 3732 KiB

Open AccessArticle

Molybdenum Oxide and Nickel Nitrate as Cooperative Sintering Aids for Yttria-Stabilized Zirconia

by Clay Hunt, John Kyle Allemeier, David Driscoll, Adam Weisenstein and Stephen Sofie

Materials 2020, 13(12), 2875; https://doi.org/10.3390/ma13122875 - 26 Jun 2020

Cited by 1 | Viewed by 2635

Abstract

The entirely accidental observation of increased sintering performance of nickel-infiltrated yttria-stabilized zirconia (8YSZ) in a molybdenum and oxygen rich atmosphere was explored. Molybdenum and nickel were found to be synergistic sintering aids for 8YSZ. However, sintering had to take place in an atmosphere [...] Read more.

The entirely accidental observation of increased sintering performance of nickel-infiltrated yttria-stabilized zirconia (8YSZ) in a molybdenum and oxygen rich atmosphere was explored. Molybdenum and nickel were found to be synergistic sintering aids for 8YSZ. However, sintering had to take place in an atmosphere of flowing oxygen. Samples sintered in air consistently burst. The sintering performance, microstructure, and crystal structure of 8YSZ with additions of both Mo and Ni together are compared to the sintering performance, microstructure, and crystal structure of pure 8YSZ, 8YSZ with only Ni added as a sintering aid, and 8YSZ with only Mo added as a sintering aid. Enhanced densification and grain growth is observed in the Mo–Ni 8YSZ samples when compared to all other sintering samples. Order of magnitude sintering rate increases are observed in the Mo–Ni 8YSZ over that of pure 8YSZ. With a maximum sintering temperature of 1200 °C and a one-hour dwell, sintered densities of 85% theoretical density (5.02 g⁄cm³) are achieved with the Mo–Ni samples: a 57% increase in density over pure 8YSZ sintered with the same sintering profile. EIS results suggest conductivity may not be negatively impacted by the use of these two sintering aids at temperatures above 750 °C. Finally, the spontaneous generation of nickel-molybdenum nano-rods was observed on the 5, and 10 mol.% Mo–Ni infiltrated 8YSZ samples after being left under vacuum in a scanning electron microscope chamber, suggesting evaporation of a possible nickel–molybdenum compound from the sample fracture surfaces. Full article

(This article belongs to the Special Issue Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications)

► Show Figures

Figure 1

17 pages, 5220 KiB

Open AccessArticle

Composite Sulfonated Polyether-Ether Ketone Membranes with SBA-15 for Electrochemical Energy Systems

by A. Rico-Zavala, J. L. Pineda-Delgado, A. Carbone, A. Saccà, E. Passalacqua, M.P. Gurrola, A. Alvarez, S. Rivas, J. Ledesma-García and L.G. Arriaga

Materials 2020, 13(7), 1570; https://doi.org/10.3390/ma13071570 - 29 Mar 2020

Cited by 4 | Viewed by 2311

Abstract

The aim of this work is the evaluation of a Sulfonated Poly Ether-Ether Ketone (S-PEEK) polymer modified by the addition of pure Santa Barbara Amorphous-15 (SBA-15, mesoporous silica) and SBA-15 previously impregnated with phosphotungstic acid (PWA) fillers (PWA/SBA-15) in order to prepare composite [...] Read more.

The aim of this work is the evaluation of a Sulfonated Poly Ether-Ether Ketone (S-PEEK) polymer modified by the addition of pure Santa Barbara Amorphous-15 (SBA-15, mesoporous silica) and SBA-15 previously impregnated with phosphotungstic acid (PWA) fillers (PWA/SBA-15) in order to prepare composite membranes as an alternative to conventional Nafion^® membranes. This component is intended to be used as an electrolyte in electrochemical energy systems such as hydrogen and methanol Proton Exchange Membrane Fuel Cell (PEMFC) and Electrochemical Hydrogen Pumping (EHP). The common requirements for all the applications are high proton conductivity, thermomechanical stability, and fuel and oxidant impermeability. The morphology of the composite membranes was investigated by Scanning Electron Microscopy- Energy Dispersive X-ray Spectroscopy (SEM-EDS) analysis. Water Uptake (Wup), Ion Exchange Capacity (IEC), proton conductivity, methanol permeability and other physicochemical properties were evaluated. In PEMFC tests, the S-PEEK membrane with a 10 wt.% SBA-15 loading showed the highest performance. For EHP, the inclusion of inorganic materials led to a back-diffusion, limiting the compression capacity. Concerning methanol permeability, the lowest methanol crossover corresponded to the composites containing 5 wt.% and 10 wt.% SBA-15. Full article

(This article belongs to the Special Issue Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications)

► Show Figures

Graphical abstract

Review

Jump to: Editorial, Research

17 pages, 4686 KiB

Open AccessReview

Research Progress of Proton Exchange Membrane Failure and Mitigation Strategies

by Yijing Xing, Haibin Li and George Avgouropoulos

Materials 2021, 14(10), 2591; https://doi.org/10.3390/ma14102591 - 16 May 2021

Cited by 51 | Viewed by 4348

Abstract

Proton exchange membrane (PEM) is critical for the efficient, reliable and safe operation of proton exchange membrane fuel cells (PEMFC). The lifetime of PEM is the main factor restricting the commercialization of PEMFC. The complexity of operating conditions, such as open-circuit/idling, dynamic load [...] Read more.

Proton exchange membrane (PEM) is critical for the efficient, reliable and safe operation of proton exchange membrane fuel cells (PEMFC). The lifetime of PEM is the main factor restricting the commercialization of PEMFC. The complexity of operating conditions, such as open-circuit/idling, dynamic load and startup-shutdown under automotive conditions, on PEMFC will cause the mechanical and chemical degradation of PEM and affect the service life of PEMFC. In order to understand the degradation behavior and durability of PEM, this paper presents an overview of the degradation failure mechanism and mitigation strategies of PEM. The mechanical and chemical degradation behavior of PEM and its causes, as well as the mitigation strategies are discussed in order to give a direction for PEM design and fuel cell system control strategy. It is proposed as a primary principle in order to further develop and promote the durability of PEM, to focus on the material improvement and system engineering. Full article

(This article belongs to the Special Issue Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (9 papers)

Editorial

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI