China Jiliang University

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTGraphene Oxide: Preparation, Functionalization, and Electrochemical ApplicationsDa Chen†‡, Hongbin Feng†, and Jinghong Li*†View Author Information† Department of Chemistry, Tsinghua University, Beijing 100084, China‡ College of Materials Science & Engineering, China Jiliang University, Hangzhou 310018, China*Tel/Fax: +86 10 6279 5290. E-mail address: [email protected]Cite this: Chem. Rev. 2012, 112, 11, 6027–6053Publication Date (Web):August 14, 2012Publication History Received4 December 2010Published online14 August 2012Published inissue 14 November 2012https://pubs.acs.org/doi/10.1021/cr300115ghttps://doi.org/10.1021/cr300115greview-articleACS PublicationsCopyright © 2012 American Chemical SocietyRequest reuse permissionsArticle Views62297Altmetric-Citations2967LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Electrodes,Materials,Peptides and proteins,Sensors,Two dimensional materials Get e-Alerts

Food security is a high-priority issue for sustainable global development both quantitatively and qualitatively. In recent decades, adverse effects of unexpected contaminants on crop quality have threatened both food security and human health. Heavy metals and metalloids (e.g., Hg, As, Pb, Cd, and Cr) can disturb human metabolomics, contributing to morbidity and even mortality. Therefore, this review focuses on and describes heavy metal contamination in soil-food crop subsystems with respect to human health risks. It also explores the possible geographical pathways of heavy metals in such subsystems. In-depth discussion is further offered on physiological/molecular translocation mechanisms involved in the uptake of metallic contaminants inside food crops. Finally, management strategies are proposed to regain sustainability in soil-food subsystems.

Graphene, as the fundamental 2D carbon structure with exceptionally high crystal and electronic quality, has emerged as a rapidly rising star in the field of material science. Its sudden discovery in 2004 led to an explosion of interest in the study of graphene with respect to its unique physical, chemical, and mechanical properties, opening up a new research area for materials science and condensed-matter physics, and aiming for wide-ranging and diversified technological applications. In this critical review, we will describe recent advances in the development of graphene-based materials from the standpoint of electrochemistry. To begin with, electron transfer properties of graphene will be discussed, involving its unusual electronic structure, extraordinary electronic properties and fascinating electron transport. The next major section deals with the exciting progress related to graphene-based materials in electrochemistry since 2004, including electrochemical sensing, electrochemiluminescence, electrocatalysis, electrochemical energy conversion and FET devices. Finally, prospects and further developments in this exciting field of graphene-based materials are also suggested (224 references).

The abundant reserve and low cost of sodium have provoked tremendous evolution of Na-ion batteries (SIBs) in the past few years, but their performances are still limited by either the specific capacity or rate capability. Attempts to pursue high rate ability with maintained high capacity in a single electrode remains even more challenging. Here, an elaborate self-branched 2D SnS 2 (B-SnS 2 ) nanoarray electrode is designed by a facile hot bath method for Na storage. This interesting electrode exhibits areal reversible capacity of ca . 3.7 mAh cm –2 (900 mAh g –1 ) and rate capability of 1.6 mAh cm –2 (400 mAh g –1 ) at 40 mA cm –2 (10 A g –1 ). Improved extrinsic pseudocapacitive contribution is demonstrated as the origin of fast kinetics of an alloying-based SnS 2 electrode. Sodiation dynamics analysis based on first-principles calculations, ex-situ HRTEM, in situ impedance, and in situ Raman technologies verify the S-edge effect on the fast Na + migration and reversible and sensitive structure evolution during high-rate charge/discharge. The excellent alloying-based pseudocapacitance and unsaturated edge effect enabled by self-branched surface nanoengineering could be a promising strategy for promoting development of SIBs with both high capacity and high rate response.

We establish an operational theory of coherence (or of superposition) in quantum systems, by focusing on the optimal rate of performance of certain tasks. Namely, we introduce the two basic concepts-"coherence distillation" and "coherence cost"-in the processing quantum states under so-called incoherent operations [Baumgratz, Cramer, and Plenio, Phys. Rev. Lett. 113, 140401 (2014)]. We, then, show that, in the asymptotic limit of many copies of a state, both are given by simple single-letter formulas: the distillable coherence is given by the relative entropy of coherence (in other words, we give the relative entropy of coherence its operational interpretation), and the coherence cost by the coherence of formation, which is an optimization over convex decompositions of the state. An immediate corollary is that there exists no bound coherent state in the sense that one would need to consume coherence to create the state, but no coherence could be distilled from it. Further, we demonstrate that the coherence theory is generically an irreversible theory by a simple criterion that completely characterizes all reversible states.

Advances in solid state white lighting technologies witness the explosive development of phosphor materials (down-conversion luminescent materials). A large amount of evidence has demonstrated the revolutionary role of the emerging nitride phosphors in producing superior white light-emitting diodes for lighting and display applications. The structural and compositional versatility together with the unique local coordination environments enable nitride materials to have compelling luminescent properties such as abundant emission colors, controllable photoluminescence spectra, high conversion efficiency, and small thermal quenching/degradation. Here, we summarize the state-of-art progress on this novel family of luminescent materials and discuss the topics of materials discovery, crystal chemistry, structure-related luminescence, temperature-dependent luminescence, and spectral tailoring. We also overview different types of nitride phosphors and their applications in solid state lighting, including general illumination, backlighting, and laser-driven lighting. Finally, the challenges and outlooks in this type of promising down-conversion materials are highlighted.

This paper provides an overview and makes a deep investigation on sampled-data-based event-triggered control and filtering for networked systems. Compared with some existing event-triggered and self-triggered schemes, a sampled-data-based event-triggered scheme can ensure a positive minimum inter-event time and make it possible to jointly design suitable feedback controllers and event-triggered threshold parameters. Thus, more attention has been paid to the sampled-data-based event-triggered scheme. A deep investigation is first made on the sampled-data-based event-triggered scheme. Then, recent results on sampled-data-based event-triggered state feedback control, dynamic output feedback control, H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> filtering for networked systems are surveyed and analyzed. An overview on sampled-data-based event-triggered consensus for distributed multiagent systems is given. Finally, some challenging issues are addressed to direct the future research.

Abstract Optical fiber gratings have developed into a mature technology with a wide range of applications in various areas, including physical sensing for temperature, strain, acoustic waves and pressure. All of these applications rely on the perturbation of the period or refractive index of a grating inscribed in the fiber core as a transducing mechanism between a quantity to be measured and the optical spectral response of the fiber grating. This paper presents a relatively recent variant of the fiber grating concept, whereby a small tilt of the grating fringes causes coupling of the optical power from the core mode into a multitude of cladding modes, each with its own wavevector and mode field shape. The main consequence of doing so is that the differential response of the modes can then be used to multiply the sensing modalities available for a single fiber grating and also to increase the sensor resolution by taking advantage of the large amount of data available. In particular, the temperature cross‐sensitivity and power source fluctuation noise inherent in all fiber grating designs can be completely eliminated by referencing all the spectral measurements to the wavelength and power level of the core mode back‐reflection. The mode resonances have a quality factor of 10 5 , and they can be observed in reflection or transmission. A thorough review of experimental and theoretical results will show that tilted fiber Bragg gratings can be used for high resolution refractometry, surface plasmon resonance applications, and multiparameter physical sensing (strain, vibration, curvature, and temperature).

Abstract Zinc‐ion batteries are under current research focus because of their uniqueness in low cost and high safety. However, it is still desirable to improve the rate performance by improving the Zn 2+ (de)intercalation kinetics and long‐cycle stability by eliminating the dendrite formation problem. Herein, the first paradigm of a high‐rate and ultrastable flexible quasi‐solid‐state zinc‐ion battery is constructed from a novel 2D ultrathin layered zinc orthovanadate array cathode, a Zn array anode supported by a conductive porous graphene foam, and a gel electrolyte. The nanoarray structure for both electrodes assures the high rate capability and alleviates the dendrite growth. The flexible Zn‐ion battery has a depth of discharge of ≈100% for the cathode and 66% for the anode, and delivers an impressive high‐rate of 50 C (discharge in 60 s), long‐term durability of 2000 cycles at 20 C, and unprecedented energy density ≈115 Wh kg −1 , together with a peak power density ≈5.1 kW kg −1 (calculation includes masses of cathode, anode, and current collectors). First principles calculations and quantitative kinetics analysis show that the high‐rate and stable properties are correlated with the 2D fast ion‐migration pathways and the introduced intercalation pseudocapacitance.

Rating-based collaborative filtering is the process of predicting how a user would rate a given item from other user ratings. We propose three related slope one schemes with predictors of the form f (x) = x + b, which precompute the average difference between the ratings of one item and another for users who rated both. Slope one algorithms are easy to implement, efficient to query, reasonably accurate, and they support both online queries and dynamic updates, which makes them good candidates for real-world systems. The basic slope one scheme is suggested as a new reference scheme for collaborative filtering. By factoring in items that a user liked separately from items that a user disliked, we achieve results competitive with slower memory-based schemes over the standard benchmark EachMovie and Movielens data sets while better fulfilling the desiderata of CF applications.

The near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) have great potential in food industry and medical fields. For applications based on NIR spectroscopy, the next generation of NIR pc-LEDs is in a high demand of a spectrum with a much broader full width at half-maximum (fwhm), which triggers the discovery of novel broadband NIR phosphors. In this work, the Cr3+-doped La2MgZrO6 (LMZ) was successfully synthesized by a conventional solid-state method in a reducing atmosphere, and the double-perovskite oxide LMZ with two distorted octahedral sites finally led to an ultra-broadband Cr3+ emission centered at 825 nm with an extremely large fwhm of 210 nm and an internal quantum efficiency of ∼58%. The experimental data and theoretical calculation confirmed that two available Cr3+ sites with different crystal field environments contributed to the broadband emission. The crystal field parameters, decay time, and temperature-dependent photoluminescence properties were investigated and discussed to further understand the luminescence of Cr3+ in LMZ:Cr. The suitability of the title NIR phosphor in multifunctional pc-LEDs was demonstrated by pumping it with blue, green, and/or red LED chips.

Nanoscale surface engineering is playing important role in enhancing the performance of battery electrode. VO2 is one of high-capacity but less-stable materials and has been used mostly in the form of powders for Li-ion battery cathode with mediocre performance. In this work, we design a new type of binder-free cathode by bottom-up growth of biface VO2 arrays directly on a graphene network for both high-performance Li-ion and Na-ion battery cathodes. More importantly, graphene quantum dots (GQDs) are coated onto the VO2 surfaces as a highly efficient surface "sensitizer" and protection to further boost the electrochemical properties. The integrated electrodes deliver a Na storage capacity of 306 mAh/g at 100 mA/g, and a capacity of more than 110 mAh/g after 1500 cycles at 18 A/g. Our result on Na-ion battery may pave the way to next generation postlithium batteries.

Hollow porous micro/nanostructures with high surface area and shell permeability have attracted tremendous attention. Particularly, the synthesis and structural tailoring of diverse hollow porous materials is regarded as a crucial step toward the realization of high-performance electrode materials, which has several advantages including a large contact area with electrolyte, a superior structural stability, and a short transport path for Li(+) ions. Meanwhile, owing to the inexpensive, abundant, environmentally benign, and renewable biological resources provided by nature, great efforts have been devoted to understand and practice the biotemplating technology, which has been considered as an effective strategy to achieve morphology-controllable materials with structural specialty, complexity, and related unique properties. Herein, we are inspired by the natural microalgae with its special features (easy availability, biological activity, and carbon sources) to develop a green and facile biotemplating method to fabricate monodisperse MnO/C microspheres for lithium-ion batteries. Due to the unique hollow porous structure in which MnO nanoparticles were tightly embedded into a porous carbon matrix and form a penetrative shell, MnO/C microspheres exhibited high reversible specific capacity of 700 mAh g(-1) at 0.1 A g(-1), excellent cycling stability with 94% capacity retention, and enhanced rate performance of 230 mAh g(-1) at 3 A g(-1). This green, sustainable, and economical strategy will extend the scope of biotemplating synthesis for exploring other functional materials in various structure-dependent applications such as catalysis, gas sensing, and energy storage.

Increased temperatures caused by global warming threaten agricultural production, as warmer conditions can inhibit plant growth and development or even destroy crops in extreme circumstances. Extensive research over the past several decades has revealed that chloroplasts, the photosynthetic organelles of plants, are highly sensitive to heat stress, which affects a variety of photosynthetic processes including chlorophyll biosynthesis, photochemical reactions, electron transport and CO2 assimilation. Important mechanisms by which plant cells respond to heat stress to protect these photosynthetic organelles have been identified and analyzed. More recent studies have made it clear that chloroplasts play an important role in inducing the expression of nuclear heat-response genes during the heat stress response. In this review, we summarize these important advances in plant-based research and discuss how the sensitivity, responses and signaling roles of chloroplasts contribute to plant heat sensitivity and tolerance.

Abstract Perovskite light‐emitting diodes (PeLEDs) are strong candidates for next‐generation display and lighting technologies due to their high color purity and low‐cost solution‐processed fabrication. However, PeLEDs are not superior to commercial organic light‐emitting diodes (OLEDs) in efficiency, as some key parameters affecting their efficiency, such as the charge carrier transport and light outcoupling efficiency, are usually overlooked and not well optimized. Here, ultrahigh‐efficiency green PeLEDs are reported with quantum efficiencies surpassing a milestone of 30% by regulating the charge carrier transport and near‐field light distribution to reduce electron leakage and achieve a high light outcoupling efficiency of 41.82%. Ni 0.9 Mg 0.1 O x films are applied with a high refractive index and increased hole carrier mobility as the hole injection layer to balance the charge carrier injection and insert the polyethylene glycol layer between the hole transport layer and the perovskite emissive layer to block the electron leakage and reduce the photon loss. Therefore, with the modified structure, the state‐of‐the‐art green PeLEDs achieve a world record external quantum efficiency of 30.84% (average = 29.05 ± 0.77%) at a luminance of 6514 cd m −2 . This study provides an interesting idea to construct super high‐efficiency PeLEDs by balancing the electron‐hole recombination and enhancing the light outcoupling.

Photovoltaic power generation forecasting is an important topic in the field of sustainable power system design, energy conversion management, and smart grid construction. Difficulties arise while the generated PV power is usually unstable due to the variability of solar irradiance, temperature, and other meteorological factors. In this paper, a hybrid ensemble deep learning framework is proposed to forecast short-term photovoltaic power generation in a time series manner. Two LSTM neural networks are employed working on temperature and power outputs forecasting, respectively. The forecasting results are flattened and combined with a fully connected layer to enhance forecasting accuracy. Moreover, we adopted the attention mechanism for the two LSTM neural networks to adaptively focus on input features that are more significant in forecasting. Comprehensive experiments are conducted with recently collected real-world photovoltaic power generation datasets. Three error metrics were adopted to compare the forecasting results produced by attention LSTM model with state-of-art methods, including the persistent model, the auto-regressive integrated moving average model with exogenous variable (ARIMAX), multi-layer perceptron (MLP), and the traditional LSTM model in all four seasons and various forecasting horizons to show the effectiveness and robustness of the proposed method.

Due to its unique atom-thick 2D structure and remarkable physicochemical properties, graphene has been making a profound impact in many areas of science and technology. In particular, a great deal of recent attention has been attracted to explore graphene and its derivatives for photoelectrochemical applications, with the potential to harness graphene's excellent properties for opening up new opportunities in next generation photoelectrochemical systems. Over the past few years, much work has been done in the design and preparation of novel graphene-based materials for a wide range of applications in photoelectrochemistry, ranging from photoelectrochemical solar cells, photocatalytic decomposition of organic pollutants, photocatalytic splitting of H2O, photocatalytic conversion for fuels, and so on. In this review article, we summarize the state of research on graphene-based materials from the standpoint of photoelectrochemistry. The prospects and further developments in this exciting field of graphene-based materials are also discussed.

Abstract Solid‐state lighting is advancing toward higher power, higher brightness, and smaller size to cope with the market competitiveness, and laser‐driven solid‐state lighting technology is springing up owing to its super‐high brightness and compactness. These developments put forward new requirements for color conversion materials (i.e., phosphors). Here, the state‐of‐art achievements in laser phosphors are summarized, and the topics of luminescence saturation, light extraction efficiency, and light uniformity encountered in laser lighting technology are discussed. Several typical types of color converters, such as single crystal, phosphor ceramics, phosphor‐in‐glass, phosphor films, and quantum‐well light‐emitting diodes, are comparatively overviewed and discussed. The cutting‐edge applications of high‐brightness white laser light in lighting, displays, healthcare, and communications are summarized. The challenges and outlook in laser‐driven solid‐state lighting and some empirical rules for designing novel laser phosphors are highlighted.

Abstract The family of transition metal carbides, nitrides, and carbonitrides (collectively called MXenes) has been a thriving field since the first invention of Ti 3 C 2 T x (MXene) in 2011. MXene is a new type of nanometer 2D sheet material, which exhibits great application potentials in various fields due to its multiple advantages such as high specific surface area, good electrical conductivity, and high mechanical strength. Electrocatalysis is regarded as the core of future clean energy conversion technologies, and MXene‐based materials provide inspiration for the design and preparation of electrocatalysts with high activity, high selectivity, and long loading life time. The applications of MXene‐based materials in electrocatalysis, including hydrogen evolution reaction, nitrogen reduction reaction, oxygen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction, and methanol oxidation reaction are summarized in this review. As a crucial session regarding experiments, the current safer and more environmentally friendly preparation methods of MXene are also discussed. Focusing on the materials design and enhancement methods, the key challenges and opportunities for MXene‐based materials as a next‐generation platform in both fundamental research and practical electrocatalysis applications are presented. This account serves to promote future efforts toward the development of MXenes and related materials in the electrocatalysis applications.

Carbon-based composite electrode materials, including carbon–carbon, carbon–metal oxide, carbon–polymer and carbon–polymer–metal oxide for efficient capacitive deionization are summarized.