scholarly journals Photocatalytic Hydrogen Evolution from Water Splitting Using Core-Shell Structured Cu/ZnS/COF Composites

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3380
Author(s):  
Wenmin Wang ◽  
Bing Li ◽  
Hsin-Ju Yang ◽  
Yuzhi Liu ◽  
Lakshmanan Gurusamy ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Active Sites ◽  
Fossil Fuels ◽  
High Energy ◽  
High Energy Density ◽  
Core Shell ◽  
Porous Network ◽  
Photocatalytic Hydrogen Production ◽  
Redox Sites

Hydrogen is considered to be a very efficient and clean fuel since it is a renewable and non-polluting gas with a high energy density; thus, it has drawn much attention as an alternative fuel, in order to alleviate the issue of global warming caused by the excess use of fossil fuels. In this work, a novel Cu/ZnS/COF composite photocatalyst with a core-shell structure was synthesized for photocatalytic hydrogen production via water splitting. The Cu/ZnS/COF microspheres formed by Cu/ZnS crystal aggregation were covered by a microporous thin-film COF with a porous network structure, where COF was also modified by the dual-effective redox sites of C=O and N=N. The photocatalytic hydrogen production results showed that the hydrogen production rate reached 278.4 µmol g−1 h−1, which may be attributed to its special structure, which has a large number of active sites, a more negative conduction band than the reduction of H+ to H2, and the ability to inhibit the recombination of electron-hole pairs. Finally, a possible mechanism was proposed to effectively explain the improved photocatalytic performance of the photocatalytic system. The present work provides a new concept, in order to construct a highly efficient hydrogen production catalyst and broaden the applications of ZnS-based materials.

scholarly journals Recent Advances in WS2 and Its Based Heterostructures for Water-Splitting Applications

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1283
Author(s):  
Zeineb Thiehmed ◽  
Abdul Shakoor ◽  
Talal Altahtamouni
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Fossil Fuels ◽  
Renewable Energy Sources ◽  
Cost Effective ◽  
High Energy ◽  
Green Energy ◽  
High Energy Density ◽  
Photocatalytic Water Splitting ◽  
Prime Concern

The energy from fossil fuels has been recognized as a main factor of global warming and environmental pollution. Therefore, there is an urgent need to replace fossil fuels with clean, cost-effective, long-lasting, and environmentally friendly fuel to solve the future energy crisis of the world. Therefore, the development of clean, sustainable, and renewable energy sources is a prime concern. In this regard, solar energy-driven hydrogen production is considered as an overriding opening for renewable and green energy by virtue of its high energy efficiency, high energy density, and non-toxicity along with zero emissions. Water splitting is a promising technology for producing hydrogen, which represents a potentially and environmentally clean fuel. Water splitting is a widely known process for hydrogen production using different techniques and materials. Among different techniques of water splitting, electrocatalytic and photocatalytic water splitting using semiconductor materials have been considered as the most scalable and cost-effective approaches for the commercial production of sustainable hydrogen. In order to achieve a high yield of hydrogen from these processes, obtaining a suitable, efficient, and stable catalyst is a significant factor. Among the different types of semiconductor catalysts, tungsten disulfide (WS2) has been widely utilized as a catalytic active material for the water-splitting process, owing to its layered 2D structure and its interesting chemical, physical, and structural properties. However, WS2 suffers from some disadvantages that limit its performance in catalytic water splitting. Among the various techniques and strategies that have been constructed to overcome the limitations of WS2 is heterostructure construction. In this process, WS2 is coupled with another semiconducting material in order to facilitate the charge transfer and prevent the charge recombination, which will enhance the catalytic performance. This review aims to summarize the recent studies and findings on WS2 and its heterostructures as a catalyst in the electrocatalytic and photocatalytic water-splitting processes.

In situ Synthesis of Nickel-Dimethylglyoxime/Black Phosphorus Nanorods for Photocatalytic Hydrogen Production from Water Splitting

NANO ◽  
2020 ◽  
Vol 15 (10) ◽  
pp. 2050125
Author(s):  
Hui’e Wang
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Active Sites ◽  
Hydrogen Generation ◽  
Hollow Structure ◽  
Black Phosphorus ◽  
In Situ Growth ◽  
Photocatalytic Hydrogen Production ◽  
Reaction Cycles

Here, a novel material consisting of black phosphorus (BP) and nickel-dimethylglyoxime nanorods was successfully prepared via a facile in situ calcination strategy, which possesses efficient catalytic activity for hydrogen production from water splitting. The reason for this phenomenon was explained by a series of characterization technologies such as SEM, TEM, XRD, UV–Vis, XPS and photoelectrochemical. We demonstrated that the fast e− transport channels were provided by the formed hollow structure of C@Ni-D nanorods, the highly exposed active sites on C@Ni-BP nanorods benefiting from the direct in situ growth of BP, the resulted synergetic effects of C@Ni-D-2 nanorods and BP achieved a better performance of photocatalytic hydrogen production from water splitting. The optimal hydrogen generation of C@Ni-BP-2 nanorods could reach up to 600[Formula: see text][Formula: see text]mol within 180[Formula: see text]min and the rate of hydrogen production did not decrease significantly after four repeated reaction cycles. This work may offer new direction in situ growth of novel catalysts for achieving highly efficient hydrogen production.

The design of 3D artificial leaves with spatially separated active sites for H2 and O2 generation and their application to water splitting

2016 ◽  
Vol 52 (21) ◽  
pp. 4080-4083 ◽  
Author(s):  
Haiyan Li ◽  
Jian Han ◽  
Na Guo ◽  
Hongwen Yu
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Active Sites ◽  
Photocatalytic Hydrogen Production ◽  
Production Activity

TiO2 artificial leaves with spatially separated CoOx and Pt cocatalysts from biotemplates have been designed and exhibit enhanced photocatalytic hydrogen-production activity.

scholarly journals Membrane-Based Electrolysis for Hydrogen Production: A Review

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 810
Author(s):  
Mohd Fadhzir Ahmad Kamaroddin ◽  
Nordin Sabli ◽  
Tuan Amran Tuan Abdullah ◽  
Shamsul Izhar Siajam ◽  
Luqman Chuah Abdullah ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Water Electrolysis ◽  
Cost Effective ◽  
High Energy ◽  
High Energy Density ◽  
Available Energy ◽  
Electrolytic Hydrogen ◽  
Production Technologies ◽  
Hydrogen Systems

Hydrogen is a zero-carbon footprint energy source with high energy density that could be the basis of future energy systems. Membrane-based water electrolysis is one means by which to produce high-purity and sustainable hydrogen. It is important that the scientific community focus on developing electrolytic hydrogen systems which match available energy sources. In this review, various types of water splitting technologies, and membrane selection for electrolyzers, are discussed. We highlight the basic principles, recent studies, and achievements in membrane-based electrolysis for hydrogen production. Previously, the NafionTM membrane was the gold standard for PEM electrolyzers, but today, cheaper and more effective membranes are favored. In this paper, CuCl–HCl electrolysis and its operating parameters are summarized. Additionally, a summary is presented of hydrogen production by water splitting, including a discussion of the advantages, disadvantages, and efficiencies of the relevant technologies. Nonetheless, the development of cost-effective and efficient hydrogen production technologies requires a significant amount of study, especially in terms of optimizing the operation parameters affecting the hydrogen output. Therefore, herein we address the challenges, prospects, and future trends in this field of research, and make critical suggestions regarding the implementation of comprehensive membrane-based electrolytic systems.

Transportation: Fuel Energies

2017 ◽  
Author(s):  
Peter Rez
Keyword(s):  
Energy Density ◽  
Fossil Fuels ◽  
High Energy ◽  
Ease Of Use ◽  
Low Energy ◽  
High Energy Density ◽  
Nuclear Fuels ◽  
Liquid Hydrocarbons ◽  
Transportation Fuel ◽  
Journey Time

Transportation efficiency can be measured in terms of the energy needed to move a person or a tonne of freight over a given distance. For passengers, journey time is important, so an equally useful measure is the product of the energy used and the time taken for the journey. Transportation requires storage of energy. Rechargeable systems such as batteries have very low energy densities as compared to fossil fuels. The highest energy densities come from nuclear fuels, although, because of shielding requirements, these are not practical for most forms of transportation. Liquid hydrocarbons represent a nice compromise between high energy density and ease of use.

scholarly journals Designing high energy density flow batteries by tuning active-material thermodynamics

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5432-5443
Author(s):  
Shyam K. Pahari ◽  
Tugba Ceren Gokoglan ◽  
Benjoe Rey B. Visayas ◽  
Jennifer Woehl ◽  
James A. Golen ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Energy Storage ◽  
Energy Density ◽  
Fossil Fuels ◽  
Active Material ◽  
High Energy ◽  
Theoretical Framework ◽  
High Energy Density ◽  
Density Flow ◽  
The Cost

With the cost of renewable energy near parity with fossil fuels, energy storage is paramount. We report a breakthrough on a bioinspired NRFB active-material, with greatly improved solubility, and place it in a predictive theoretical framework.

scholarly journals Hydrogen production from water electrolysis: role of catalysts

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Shan Wang ◽  
Aolin Lu ◽  
Chuan-Jian Zhong
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Noble Metal ◽  
Active Sites ◽  
Current Knowledge ◽  
Low Cost ◽  
Critical Role ◽  
Water Electrolysis ◽  
Efficient Production ◽  
Production Of Hydrogen

AbstractAs a promising substitute for fossil fuels, hydrogen has emerged as a clean and renewable energy. A key challenge is the efficient production of hydrogen to meet the commercial-scale demand of hydrogen. Water splitting electrolysis is a promising pathway to achieve the efficient hydrogen production in terms of energy conversion and storage in which catalysis or electrocatalysis plays a critical role. The development of active, stable, and low-cost catalysts or electrocatalysts is an essential prerequisite for achieving the desired electrocatalytic hydrogen production from water splitting for practical use, which constitutes the central focus of this review. It will start with an introduction of the water splitting performance evaluation of various electrocatalysts in terms of activity, stability, and efficiency. This will be followed by outlining current knowledge on the two half-cell reactions, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), in terms of reaction mechanisms in alkaline and acidic media. Recent advances in the design and preparation of nanostructured noble-metal and non-noble metal-based electrocatalysts will be discussed. New strategies and insights in exploring the synergistic structure, morphology, composition, and active sites of the nanostructured electrocatalysts for increasing the electrocatalytic activity and stability in HER and OER will be highlighted. Finally, future challenges and perspectives in the design of active and robust electrocatalysts for HER and OER towards efficient production of hydrogen from water splitting electrolysis will also be outlined.

Enhanced dielectric properties and thermostability in polyimide composites with core-shell structured polyimide@BaTiO3 nanoparticles

2021 ◽  
pp. 095400832199352
Author(s):  
Wei Deng ◽  
Guanguan Ren ◽  
Wenqi Wang ◽  
Weiwei Cui ◽  
Wenjun Luo
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Energy Density ◽  
Breakdown Strength ◽  
In Situ Polymerization ◽  
Dielectric Materials ◽  
High Energy ◽  
Amic Acid ◽  
High Energy Density ◽  
Core Shell

Polymer composites with high dielectric constant and thermal stability have shown great potential applications in the fields relating to the energy storage. Herein, core-shell structured polyimide@BaTiO3 (PI@BT) nanoparticles were fabricated via in-situ polymerization of poly(amic acid) (PAA) and the following thermal imidization, then utilized as fillers to prepare PI composites. Increased dielectric constant with suppressed dielectric loss, and enhanced energy density as well as heat resistance were simultaneously realized due to the presence of PI shell between BT nanoparticles and PI matrix. The dielectric constant of PI@BT/PI composites with 55 wt% fillers increased to 15.0 at 100 Hz, while the dielectric loss kept at low value of 0.0034, companied by a high energy density of 1.32 J·cm−3, which was 2.09 times higher than the pristine PI. Moreover, the temperature at 10 wt% weight loss reached 619°C, demonstrating the excellent thermostability of PI@BT/PI composites. In addition, PI@BT/PI composites exhibited improved breakdown strength and toughness as compared with the BT/PI composites due to the well dispersion of PI@BT nanofillers and the improved interfacial interactions between nanofillers and polymer matrix. These results provide useful information for the structural design of high-temperature dielectric materials.

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