36,989 research outputs found
Anisotropic-cyclicgraphene: A new two-dimensional semiconducting carbon allotrope
Potentially new, single-atom thick semiconducting 2D-graphene-like material,
called Anisotropic-cyclicgraphene, have been generated by the two stage
searching strategy linking molecular and ab initio approach. The candidate
derived from the evolutionary based algorithm and molecular simulations was
then profoundly analysed using first-principles density functional theory from
the structural, mechanical, phonon, and electronic properties point of view.
The proposed polymorph of graphene (rP16-P1m1) is mechanically, dynamically,
and thermally stable and can be semiconducting with a direct band gap of 0.829
eV.Comment: 15 pages, 14 figure
Nanostructured Conductive Polymers for Advanced Energy Storage
Conductive polymers combine the attractive properties associated with conventional polymers and unique electronic properties of metals or semiconductors. Recently, nanostructured conductive polymers have aroused considerable research interest owing to their unique properties over their bulk counterparts, such as large surface areas and shortened pathways for charge/mass transport, which make them promising candidates for broad applications in energy conversion and storage, sensors, actuators, and biomedical devices. Numerous synthetic strategies have been developed to obtain various conductive polymer nanostructures, and high-performance devices based on these nanostructured conductive polymers have been realized. This Tutorial review describes the synthesis and characteristics of different conductive polymer nanostructures; presents the representative applications of nanostructured conductive polymers as active electrode materials for electrochemical capacitors and lithium-ion batteries and new perspectives of functional materials for next-generation high-energy batteries, meanwhile discusses the general design rules, advantages, and limitations of nanostructured conductive polymers in the energy storage field; and provides new insights into future directions.University of Texas at Austin3M Non-tenured Faculty awardWelch Foundation F-1861Materials Science and Engineerin
Cross-linked CoMoO4/rGO nanosheets as oxygen reduction catalyst
Development of inexpensive and robust electrocatalysts towards oxygen reduction reaction
(ORR) is crucial for the cost-affordable manufacturing of metal-air batteries and fuel cells. Here
we show that cross-linked CoMoO4 nanosheets and reduced graphene oxide (CoMoO4/rGO) can
be integrated in a hybrid material under one-pot hydrothermal conditions, yielding a composite
material with promising catalytic activity for oxygen reduction reaction (ORR). Cyclic voltammetry
(CV) and linear sweep voltammetry (LSV) were used to investigate the efficiency of the fabricated
CoMoO4/rGO catalyst towards ORR in alkaline conditions. The CoMoO4/rGO composite revealed
the main reduction peak and onset potential centered at 0.78 and 0.89 V (vs. RHE), respectively.
This study shows that the CoMoO4/rGO composite is a highly promising catalyst for the ORR under
alkaline conditions, and potential noble metal replacement cathode in fuel cells and metal-air batteries
Recent Developments in Synthesis and Photocatalytic Applications of Carbon Dots
The tunable photoluminescent and photocatalytic properties of carbon dots (CDs) via chemical surface modification have drawn increased attention to this emerging class of carbon nanomaterials. Herein, we summarize the advances in CD synthesis and modification, with a focus on surface functionalization, element doping, passivation, and nanocomposite formation with metal oxides, transition metal chalcogenides, or graphitic carbon nitrides. The effects of CD size and functionalization on photocatalytic properties are discussed, along with the photocatalytic applications of CDs in energy conversion, water splitting, hydrogen evolution, water treatment, and chemical degradation. In particular, the enzyme-mimetic and photodynamic applications of CDs for bio-related uses are thoroughly reviewed
Graphene-Based Nanostructures in Electrocatalytic Oxygen Reduction
Application of graphene-type materials in electrocatalysis is a topic of
growing scientific and technological interest. A tremendous amount of research
has been carried out in the field of oxygen electroreduction, particularly with
respect to potential applications in the fuel cell research also with use of
graphene-type catalytic components. This work addresses fundamental aspects and
potential applications of graphene structures in the oxygen reduction
electrocatalysis. Special attention will be paid to creation of catalytically
active sites by using non-metallic heteroatoms as dopants, formation of
hierarchical nanostructured electrocatalysts, their long-term stability, and
application as supports for dispersed metals (activating interactions)
Nanostructured semiconductor materials for dye-sensitized solar cells
Since O'Regan and Grätzel's first report in 1991, dye-sensitized solar cells (DSSCs) appeared immediately as a promising low-cost photovoltaic technology. In fact, though being far less efficient than conventional silicon-based photovoltaics (being the maximum, lab scale prototype reported efficiency around 13%), the simple design of the device and the absence of the strict and expensive manufacturing processes needed for conventional photovoltaics make them attractive in small-power applications especially in low-light conditions, where they outperform their silicon counterparts. Nanomaterials are at the very heart of DSSC, as the success of its design is due to the use of nanostructures at both the anode and the cathode. In this review, we present the state of the art for both n-type and p-type semiconductors used in the photoelectrodes of DSSCs, showing the evolution of the materials during the 25 years of history of this kind of devices. In the case of p-type semiconductors, also some other energy conversion applications are touched upon. © 2017 Carmen Cavallo et al
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