p.6
Nanocatalysts for MgH2
What type of nanoparticles were synthesized to improve hydrogen storage properties of MgH2?
ZrMn2 intermetallic nanoparticles with sizes ranging from 100 to 300 nm.
p.2
Nanocatalysts for MgH2
What effect do TiC nanoparticles have on the dehydrogenation temperatures of MgH2?
They reduce the onset and peak temperatures of H2 desorption to 190 °C and 280 °C, respectively.
p.4
Nanocatalysts for MgH2
What hydrogen absorption capacity was achieved by the Mg-Ti nanocomposite at room temperature?
6.2 wt% H2 within 2 hours at 3 MPa.
p.9
Nanostructuring Methods for MgH2
How were Mg nanoparticles synthesized?
By reducing di-n-butylmagnesium (MgBu2) in THF solution containing lithium and naphthalene.
p.2
Nanocatalysts for MgH2
Why are nanoscale catalysts more effective than conventional catalysts for MgH2?
They generate more active catalytic sites due to intimate contacts with MgH2.
p.3
Nanocatalysts for MgH2
What is the significance of Ti in the MgH2 nanocrystalline preparation?
Ti catalyzes the reaction of Mg with anthracene and TiCl4 in THF solution.
p.2
Thermodynamics and Kinetics of MgH2
What are the main challenges in the kinetics of MgH2?
High thermal stability (ΔH = 76 kJ/mol) and kinetic barrier (Ea = 160 kJ/mol).
p.5
Nanocatalysts for MgH2
Which transition metal compounds have been developed to improve the hydrogen-storage properties of MgH2?
Nb, V, Co, Fe, Zr, and Ce-based compounds.
p.3
Thermodynamics and Kinetics of MgH2
What was the hydrogen absorption capacity of the Mg-TiH nanocomposite at room temperature?
4.3 wt% H2 in 10 minutes.
p.2
Nanocatalysts for MgH2
What is the significance of Na2Ti3O7 nanotubes in improving MgH2 performance?
They showed superior catalytic effects, lowering the onset dehydrogenation temperature significantly.
p.9
Thermodynamics and Kinetics of MgH2
What was the hydrogen absorption and release temperature for Mg nano fibers?
Absorbed at 300 °C and released at 360 °C.
p.9
Nanostructuring Methods for MgH2
What is the impact of Grignard reagents on MgH2 synthesis?
The types of Mg precursors and synthesis conditions significantly influence the morphologies and hydrogen storage properties.
p.7
Thermodynamics and Kinetics of MgH2
What was the hydrogen absorption capacity of the Mg@Ni8Gn2 composite at 100 °C?
6.28 wt% of hydrogen in 100 seconds.
p.8
Recent Advances in Nanocatalysts
What are metal-organic frameworks (MOFs) used for in this context?
To synthesize carbon-wrapped transition metal catalysts.
p.2
Nanostructuring Methods for MgH2
What strategies have been proposed to improve the thermodynamics and kinetics of MgH2?
Alloying, nanostructuring, and catalyzing.
p.9
Nanostructuring Methods for MgH2
What happens to the size of Mg nanoparticles with increasing lithium/naphthalene ratios?
The particle size decreases.
p.4
Nanocatalysts for MgH2
What role does multiple valence Ti play in the MgH2 system?
Acts as intermediate and catalytic active sites for electron transfers.
p.4
Bimetallic and Metal/Carbon Composite Catalysts
What effect does Ni doping have on MgH2?
It significantly decreases the activation energy for hydrogen desorption.
p.4
Recent Advances in Nanocatalysts
What type of nanoparticles were synthesized to lower the onset temperature of dehydrogenation to 180 °C?
Amorphous NiB nanoparticles.
p.1
Thermodynamics and Kinetics of MgH2
What barriers does MgH2 face for practical use?
Challenges in thermodynamics and kinetics.
p.8
Nanocatalysts for MgH2
What method was used to synthesize nanocrystalline Ni@C and Co@C?
By calcining a mixture of LiOH·H2O, benzimidazole, and Ni(NO3)2·6H2O/Co(NO3)2·6H2O at low temperatures.
p.8
Nanocatalysts for MgH2
What was the hydrogen absorption capacity of the MgH2-5 wt% Ni@C composite at 150 °C?
5.0 wt% H2 within 40 seconds.
p.9
Thermodynamics and Kinetics of MgH2
What factors influence hydrogen sorption kinetics in Mg nanocrystallines?
Defect sites in the Mg nanocrystallines.
p.6
Bimetallic and Metal/Carbon Composite Catalysts
What is the advantage of using carbon as a supporting material for metal nanoparticles?
It helps overcome agglomeration and growth during hydrogen sorption, increasing catalytic efficiency.
p.3
Nanocatalysts for MgH2
What method was used to obtain the Mg-TiH nanocomposite that quickly absorbed hydrogen?
Hydrogen plasma-metal reaction (HPMR) method.
p.1
Nanotechnology in Hydrogen Storage
How can nanotechnology improve MgH2 performance?
By employing nanocatalysts and reducing particle size to nanoscale.
p.8
Recent Advances in Nanocatalysts
What was the particle size range for Co@C and Ni@C nanoparticles obtained from MOFs?
8-10 nm for Co@C and 12-16 nm for Ni@C.
p.4
Thermodynamics and Kinetics of MgH2
What temperature was required to release 5 wt% H2 from the Ti-coated Mg composite?
250 °C within 15 minutes.
p.8
Nanocatalysts for MgH2
What is the significance of the TiO2@C catalyst in hydrogen storage?
It reduces the dehydrogenation onset temperature to 205 °C and releases 6.7 wt% H2 within 7 minutes at 300 °C.
p.9
Challenges in Hydrogen Storage
What effect does replacing Li with Na or K have on Mg nanoparticles?
It results in the formation of NaMgH3 and KMgH3 perovskite structures, enhancing cycle stability.
p.5
Bimetallic and Metal/Carbon Composite Catalysts
What is the hydrogen absorption and desorption performance of the Ni-doped TiO2 nanocatalyst?
Absorbed 4.5 wt% H2 at 50 °C and desorbed 5.24 wt% H2 in 1800 seconds at 250 °C.
p.5
Bimetallic and Metal/Carbon Composite Catalysts
What role does Ni play in the NiTiO3 enhanced MgH2 system?
Ni provides hydrogen diffusion channels and heterogeneous nucleation sites for easy H2 release.
p.6
Bimetallic and Metal/Carbon Composite Catalysts
Which composite showed higher catalytic activity for MgH2: carbon-supported nano nickel or a physical mixture of nickel and carbon?
Carbon-supported nano nickel particles.
p.5
Bimetallic and Metal/Carbon Composite Catalysts
What is the performance of the Mg@Ti@Ni composite compared to Mg@Ti?
Mg@Ti@Ni shows better hydrogen storage performance than Mg@Ti.
p.2
Nanocatalysts for MgH2
How does the addition of TiO2 nanosheets affect the kinetic performance of MgH2?
It allows for the release of 6.0 wt% hydrogen within 3.2 minutes at 260 °C.
p.8
Nanostructuring Methods for MgH2
What effect does nanostructuring have on MgH2?
It increases specific surface areas and provides more active sites for hydrogen absorption and dissociation.
p.2
Nanocatalysts for MgH2
What is the hydrogen absorption capacity of a MgH2-0.1TiH2 nanocomposite?
It can absorb hydrogen at room temperature and maintain capacity over 80 cycles.
p.8
Thermodynamics and Kinetics of MgH2
What is the effect of particle size below 10 nm on MgH2?
It can lead to thermodynamic destabilization of MgH2.
p.1
Nanotechnology in Hydrogen Storage
What are the two main strategies discussed for enhancing MgH2 performance?
Using nanocatalysts and nanostructuring methods.
p.1
Challenges in Hydrogen Storage
What is a significant challenge for onboard hydrogen storage?
Safe, efficient, and economical hydrogen storage.
p.6
Thermodynamics and Kinetics of MgH2
What did density functional theory calculations reveal about ZrMn2's effect on MgH2?
ZrMn2 elongated the Mg-H bond length and weakened the Mg-H bond, enhancing kinetics.
p.9
Nanostructuring Methods for MgH2
What effect does the synthetic medium have on the morphology of MgH2?
It varies the size and shape of the nanoparticles.
p.7
Thermodynamics and Kinetics of MgH2
What advantage does the MgH2-Co/Pd@B-CNTs composite have in terms of hydrogen absorption?
It can absorb 6.68 wt% H2 within 10 seconds at 250 °C.
p.1
Challenges in Hydrogen Storage
What are the current hydrogen storage methods mentioned?
High-pressure gaseous storage, cryogenic liquid storage, and solid-state storage.
p.5
Nanocatalysts for MgH2
What was the hydrogen absorption rate of MgH2 doped with 0.2 mol% Nb2O5 at 300 °C?
6.9 wt% H2 within 60 seconds.
p.2
Nanocatalysts for MgH2
What unique structure does Ti3C2 MXene have, and how does it affect MgH2?
It has a unique layer structure that enhances catalytic activity, lowering the onset dehydrogenation temperature to 185 °C.
p.5
Bimetallic and Metal/Carbon Composite Catalysts
What was the hydrogen desorption performance of the 10 wt% TiVO3.5-containing MgH2 at 250 °C?
Desorbed 5.0 wt% H2 in 10 minutes.
p.9
Thermodynamics and Kinetics of MgH2
What was observed about the hydrogenolysis temperatures and their effect on MgH2 morphology?
Higher temperatures led to different particle shapes and sizes, affecting desorption performance.
p.7
Nanocatalysts for MgH2
What method was used to prepare the Ni/Gn-MgH2 composite?
Hydriding combustion synthesis (HCS) method.
p.7
Nanocatalysts for MgH2
What is the effect of the Ni@C nanorod structure on MgH2?
It restricts the growth and agglomeration of Ni nanoparticles and MgH2 grains, enhancing catalytic effect.
p.5
Nanocatalysts for MgH2
What special species formed in situ improve hydrogen absorption kinetics in Nb-based compounds?
NbHx, NbO, and MgNb x O y.
p.7
Nanocatalysts for MgH2
What role do dispersive Ni particles play in the Ni/Gn-MgH2 composite?
They act as nucleation sites to facilitate the nucleation of Mg on graphene nanoplate.
p.7
Nanocatalysts for MgH2
What is the significance of using multiwall carbon nanotubes (MWCNTs) in catalysts?
They support metal composites like Pd/MWCNTs and enhance hydrogen absorption and desorption kinetics.
p.5
Nanocatalysts for MgH2
What effect does the size and disorder of NbHx nanoparticles have on catalytic activity?
Smaller and more disordered NbHx nanoparticles exhibit higher catalytic activity.
p.6
Nanocatalysts for MgH2
What effect does TiN@rGO have on the dehydrogenation onset temperature of MgH2?
It reduces the onset temperature to 167 °C from 307 °C.
p.2
Nanocatalysts for MgH2
What is the role of catalyst doping in MgH2 systems?
It effectively relieves the de-/rehydrogenation energy barrier.
p.7
Nanocatalysts for MgH2
What was the performance of the MgH2 plus Ni-VOx/AC composite in hydrogen absorption?
It absorbed 6.2 wt% H2 within just 1 minute at 150 °C.
p.3
Bimetallic and Metal/Carbon Composite Catalysts
What is the effect of doping MgH2 with Nb on its hydrogen storage properties?
It shows a capacity of 7.0 wt% at 237 °C.
p.7
Nanocatalysts for MgH2
What transformation occurs to Ni during the reaction with Mg?
Ni is transformed into Mg2Ni.
p.7
Thermodynamics and Kinetics of MgH2
What was the hydrogen absorption capacity of the Mg95-(Pd3Ni3/MWCNTs4)5 composite at 100 °C?
6.44 wt% H2 within 100 seconds.
p.7
Nanocatalysts for MgH2
What unique structure was created by using bamboo-shaped carbon nanotubes (B-CNTs)?
Co/Pd nanoparticles were dispersed, with Pd nanoparticles attached to the walls and Co nanoparticles at the tips.
p.1
Magnesium Hydride (MgH2) Properties
What is magnesium hydride (MgH2) considered for?
One of the most promising candidates for solid-state hydrogen storage.
p.1
Magnesium Hydride (MgH2) Properties
What are the advantages of MgH2 as a hydrogen storage medium?
High hydrogen capacity, excellent reversibility, and low cost.
