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1.
Small ; 15(16): e1900015, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30924269

RESUMO

Transition metal oxides (TMOs) are regarded as promising candidates for anodes of lithium ion batteries, but their applications have been severely hindered by poor material conductivity and lithiated volume expansion. As a potential solution, herein is presented a facile approach, by electrospinning a manganese-based metal organic framework (Mn-MOF), to fabricate yolk-shell MnOx nanostructures within carbon nanofibers in a botryoid morphology. While the yolk-shell structure accomodates the lithiated volume expansion of MnOx , the fiber confinement ensures the structural integrity during charge/discharge, achieving a so-called double-buffering for cyclic volume fluctuation. The formation mechanism of the yolk-shell structure is well elucidated through comprehensive instrumental characterizations and cogitative control experiments, following a combined Oswald ripening and Kirkendall process. Outstanding electrochemical performances are demonstrated with prolonged stability over 1000 cycles, boosted by the double-buffering design, as well as the "breathing" effect of lithiation/delithiation witnessed by ex situ imaging. Both the fabrication methodology and electrochemical understandings gained here for nanostructured MnOx can also be extended to other TMOs toward their ultimate implementation in high-performance lithium ion batteries (LIBs).

2.
Adv Sci (Weinh) ; : e2205077, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36398622

RESUMO

Electro-organic synthesis has attracted a lot of attention in pharmaceutical science, medicinal chemistry, and future industrial applications in energy storage and conversion. To date, there has not been a detailed review on electro-organic synthesis with the strategy of heterogeneous catalysis. In this review, the most recent advances in synthesizing value-added chemicals by heterogeneous catalysis are summarized. An overview of electrocatalytic oxidation and reduction processes as well as paired electrocatalysis is provided, and the anodic oxidation of alcohols (monohydric and polyhydric), aldehydes, and amines are discussed. This review also provides in-depth insight into the cathodic reduction of carboxylates, carbon dioxide, CC, C≡C, and reductive coupling reactions. Moreover, the electrocatalytic paired electro-synthesis methods, including parallel paired, sequential divergent paired, and convergent paired electrolysis, are summarized. Additionally, the strategies developed to achieve high electrosynthesis efficiency and the associated challenges are also addressed. It is believed that electro-organic synthesis is a promising direction of organic electrochemistry, offering numerous opportunities to develop new organic reaction methods.

3.
Front Chem ; 10: 1063288, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36578353

RESUMO

Photocatalytic hydrogen generation from direct water splitting is recognized as a progressive and renewable energy producer. The secret to understanding this phenomenon is discovering an efficient photocatalyst that preferably uses sunlight energy. Two-dimensional (2D) graphitic carbon nitride (g-C3N4)-based materials are promising for photocatalytic water splitting due to special characteristics such as appropriate band gap, visible light active, ultra-high specific surface area, and abundantly exposed active sites. However, the inadequate photocatalytic activity of pure 2D layered g-C3N4-based materials is a massive challenge due to the quick recombination between photogenerated holes and electrons. Creating 2D heterogeneous photocatalysts is a cost-effective strategy for clean and renewable hydrogen production on a larger scale. The 2D g-C3N4-based heterostructure with the combined merits of each 2D component, which facilitate the rapid charge separation through the heterojunction effect on photocatalyst, has been evidenced to be very effective in enhancing the photocatalytic performance. To further improve the photocatalytic efficiency, the development of novel 2D g-C3N4-based heterostructure photocatalysts is critical. This mini-review covers the fundamental concepts, recent advancements, and applications in photocatalytic hydrogen production. Furthermore, the challenges and perspectives on 2D g-C3N4-based heterostructure photocatalysts demonstrate the future direction toward sustainability.

4.
Adv Sci (Weinh) ; 9(2): e2102530, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34859614

RESUMO

Artificial Z-scheme, a tandem structure with two-step excitation process, has gained significant attention in energy production and environmental remediation. By effectively connecting and matching the band-gaps of two different photosystems, it is significant to utilize more photons for excellent photoactivity. Herein, a novel one-photon (same energy-two-photon) Z-scheme system is constructed between rGO modified boron-nitrogen co-doped-WO3 , and coupled CdSe quantum dots-(QDs). The coctalyst-0.5%Rhx Cr2 O3 (0.5RCr) modified amount-optimized sample 6%CdSe/1%rGO3%BN-WO3 revealed an unprecedented visible-light driven overall-water-splitting to produce ≈51 µmol h-1 g-1 H2 and 25.5 µmol h-1 g-1 O2 , and it remained unchanged for 5 runs in 30 h. This superior performance is ascribed to the one-photon Z-scheme, which simultaneously stimulates a two photocatalysts system, and enhanced charge separation as revealed by various spectroscopy techniques. The density-functional theory is further utilized to understand the origin of this performance enhancement. This work provides a feasible strategy for constructing an efficient one-photon Z-scheme for practical applications.

5.
J Pak Med Assoc ; 61(8): 828-32, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22356017

RESUMO

OBJECTIVE: To assess the level of awareness and ethical issues related to organ donation especially kidney donation and the willingness to donate a kidney among the rural population of Pakistan. METHOD: A cross sectional study was conducted in a sample of 324 subjects residing in Nurpur Shahan by means of a pre tested questionnaire. Data collection was carried out via a face to face interview and the data was analyzed using SPSS 10.0 and associations were tested using the Chi-square test. RESULTS: Knowledge about organ donation was significantly associated with age (p = 0.00) and education (p = 0.024). Allowance of organ donation in religion was an important factor in determining the attitude of individuals towards organ donation and their willingness to donate. Media emerged as a major source of information for the population of Nurpur Shahan; kidney was the organ most known for its donation. Most (69%) respondents did not consider organ vending to be ethically correct but a sizeable proportion (25%) thought it may be considered in times of dire need. CONCLUSION: Awareness of organ donation in our sample was high and more than half of the people were willing to become donors.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Transplante de Rim/psicologia , População Rural , Doadores de Tecidos/psicologia , Obtenção de Tecidos e Órgãos , Adolescente , Adulto , Fatores Etários , Idoso , Conscientização , Estudos Transversais , Cultura , Feminino , Humanos , Entrevistas como Assunto , Rim , Masculino , Pessoa de Meia-Idade , Paquistão , Fatores Socioeconômicos , Inquéritos e Questionários , Adulto Jovem
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