1,721,067 research outputs found
South Africa launches new hydrogen energy storage research centre
No full textThe South African Department
of Science & Technology (DST)
has launched a suite of laboratories
dedicated to hydrogen and energy
storage research, at the Council for
Scientific and Industrial Research
(CSIR) in Pretoria. The new facility
will be jointly used by Hydrogen
South Africa (HySA) and the Batteries
Research Centre, for research to
develop novel materials that meet
the challenging requirements for
hydrogen and energy storagehttp://www.sciencedirect.com/science/article/pii/S1464285914703505doi:10.1016/S1464-2859(14)70350-
Theoretical limit of reversible hydrogen storage capacity for pristine and oxygen-doped boron nitride
No full textTo achieve higher hydrogen storage capacity than that of compressed gas vessels, new advanced materials must be developed. Among the most promising are two-dimensional layered nanomaterials, such as graphene and boron nitride, storing hydrogen via physisorption which is potentially reversible at relatively low pressures. Unlike graphene, boron nitride is a polar material that makes it potentially more attractive for hydrogen physisorption. To quickly evaluate storage capacity of novel materials an efficient theoretical tool is proposed. A customized model combining quantum simulation with thermodynamic calculation is developed and applied for pristine and oxygen-doped boron nitride materials. It is shown that pristine boron nitride has a maximum reversible hydrogen storage capacity of 1.5 wt.% under 5 MPa at room temperature. Oxygen doping increases the capacity to 1.9 wt.% under the same conditions by deepening and widening the adsorption potential. Both gravimetric and volumetric storage properties are found to be strong functions of the interlayer separation distance of the material, with an optimum distance near 7 Å. The present results indicate that pristine and oxygen doped boron nitride materials have a suitable base configuration for potentially high reversible hydrogen storag
PEM electrolysis for hydrogen production: principles and applications
No full textAn ever-increasing dependence on green energy has brought on a renewed interest in polymer electrolyte membrane (PEM) electrolysis as a viable solution for hydrogen production. While alkaline water electrolyzers have been used in the production of hydrogen for many years, there are certain advantages associated with PEM electrolysis and its relevance to renewable energy sources. PEM Electrolysis for Hydrogen Production: Principles and Applications discusses the advantages of PEM electrolyzers over alkaline electrolyzers, presents the recent advances of hydrogen PEM fuel cells accelerating the large-scale commercialization of PEM electrolysis, and considers the challenges that must be addressed before PEM electrolysis can become a commercially feasible option.
Written by international scientists in PEM electrolysis and fuel cell research areas, this book addresses the demand for energy storage technologies that store intermittent renewable energy and offers the most complete and up-to-date information on PEM electrolysis technology and researc
Aromatic liquid organic hydrogen carriers for hydrogen storage and release
Get PDFHydrogen production from renewable energy sources has the
potential to significantly reduce the carbon footprint of critical
economic sectors that rely heavily on fossil fuels. Liquid
organic hydrogen carrier (LOHC) technology has the capability
to overcome the limitations associated with conventional
hydrogen storage technologies. To date, dibenzyltoluene and
benzyltoluene are the benchmark LOHC molecules due to the
unique hydrogen storage properties. However, the reaction
temperature for dehydrogenation reaction is high and catalysts
need to be further developed so that efficient release of
hydrogen can be realized. Exploration of various catalyst
preparation methods such as supercritical carbon-dioxide
deposition, the selection on support material with relevant
textural and chemical properties and optimization of catalyst
modifiers are rewarding approaches of improving the catalyst
performance. In addition to this, the lowering of the dehydro
genation temperature by employing electrochemical methods
and reactive distillation approaches are strategies that will
make the LOHC technology competitive
Low cost hydrogen production by anion exchange membrane electrolysis: A review
No full textAnion exchange membrane (AEM) water electrolysis is a hydrogen production method that is achieved with an AEM, using electricity. One of the major advantages of AEM water electrolysis is the replacement of conventional noble metal electrocatalysts with low cost transition metal catalysts. AEM electrolysis is still a developing technology; therefore, with a view to using it to eventually achieve commercially viable hydrogen production, AEM electrolysis requires further investigation and improvements, specifically regarding its power efficiency, membrane stability, robustness, ease of handling, and cost reduction.
This review addresses state of the art technology of AEM electrolysis for hydrogen production. It also provides a summary of important research that has been carried out on membranes, electrocatalysts, and ionomers used in AEM electrolyzers, and the performance of such electrolyzers. The aim of this review is to identify gaps in AEM water electrolysis research and to make recommendations for future directions in AEM water electrolysis researc
Electrochemical Characterization and Oxygen Reduction Kinetics of Cu-incorporated Cobalt Oxide Catalyst
Get PDFElectrochem
ical characterization of Cu incorporated cobalt oxide is carried out and
oxygen reduction
reaction
(ORR) activity also determined at different catalyst loadings (CLs), using thin film
rotating
disk electrode (RDE)
technology. E
lectrochemical properties such as the electrochemical surface area
(ECSA), ORR, mass activity specific activity, as well as the durability of the electrocatalyst is
evaluated.
ESCA is determined by cyclic voltammetry (CV) measurements in
1 M KOH
at 30
C,
using scanning rates of 5
–
100 mV s
–
1
. The active CO
3
+
present in the surface of the
(CuCoO)
x
lattice
acts as a donor
–
acceptor in the reduction sites during the ORR.
The o
xygen reduction activity for
(CuCoO)
x
catalysts is evaluated at various rotation rate
in the range 400
–
3000 rpm.
The data are
analysed using the Koutecky
–
Levich relationship;
parallel lines indicate first
-
order kinetics.
The
number of electrons
transfer
favours
a 4e
-
pathway
oxygen reduction process
, the rate constant of the
reaction is in
the range 0.07
–
0.11 mol L
–
1
s
–
1
at CL 0.05 mg cm
–
Modeling hydrogen storage in boron-substituted graphene decorated with potassium metal atoms
No full textBoron-substituted graphene decorated with potassium metal atoms was considered as a novel material for hydrogen
storage. Density functional theory calculations were used to model key properties of the material, such as geometry,
hydrogen packing, and hydrogen adsorption energy. We found that the new material has extremely high hydrogen
storage capacity: 22.5wt%. It is explained by high-density packing of hydrogen molecules into hydrogen layers with
specific geometry. In turn, such geometry is determined by the composition and topology of the materialDepartment of
Science and Technology for funding through the Hydrogen
South Africa progra
Modulated synthesis of zirconium-metal organic framework (Zr-MOF) for hydrogen storage applications
No full textA modulated synthesis of Zr-metal organic framework (Zr-MOF) with improved ease of handling and decreased reaction time is reported to yield highly crystalline Zr-MOF with well-defined octahedral shaped crystals for practical hydrogen storage applications. The Zr-MOF obtained from the modulated synthesis showed high thermal and moisture stabilities with enhanced hydrogen storage capacity. Further study suggests that the modulated synthesis of Zr-MOF may lead to the development of a flow-through synthesis proces
Low equivalent weight short-side-chain perfluorosulfonic acid ionomers in fuel cell cathode catalyst layers
No full textThe morphology and fuel cell performance of cathode catalyst layers (CCLs) using low equivalent weight (EW) short-side-chain (SSC) perfluorosulfonic acid ionomers have been investigated in this work. The results were compared with those for a baseline CCL containing 30 wt% of the conventional ionomer 1100 EW Nafion�. The CCLs fabricated with 10�20 wt% of the Aquivion� ionomer displayed a similar morphology to the Nafion�-based CCLs. Electrochemical surface areas (ECSA) and double layer capacitances of all the Aquivion�-based samples were similar to those of the baseline. The oxygen reduction reaction (ORR) kinetics in CCLs with 20 wt% and 30 wt% Aquivion� were lower than the baseline under 100% relative humidity (RH), yet similar to the baseline at 70% RH. In situ electrochemical impedance spectroscopy (EIS) measurements suggested that the lowered ORR kinetics at 100% RH may be attributed to the large mass transport resistance in Aquivion�-based samples at low current densities. Relative to the baseline, CCLs containing 20 wt% Aquivion� ionomer demonstrated an improvement in fuel cell performance under operating conditions of 95 �C and RH values of 30, 50 and 70%. The greater hydrophilicity of the SSC ionomers is believed to account for the improved fuel cell performance at the relatively higher operating temperature and dry conditions
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