South Central Minzu University

Large-scale synthesis of aligned carbon nanotubes was achieved by using a method based on chemical vapor deposition catalyzed by iron nanoparticles embedded in mesoporous silica. Scanning electron microscope images show that the nanotubes are approximately perpendicular to the surface of the silica and form an aligned array of isolated tubes with spacings between the tubes of about 100 nanometers. The tubes are up to about 50 micrometers long and well graphitized. The growth direction of the nanotubes may be controlled by the pores from which the nanotubes grow.

Graphitic carbon nitride, g-C3N4, is a polymeric material consisting of C, N, and some impurity H, connected via tris-triazine-based patterns. Compared with the majority of carbon materials, it has electron-rich properties, basic surface functionalities and H-bonding motifs due to the presence of N and H atoms. It is thus regarded as a potential candidate to complement carbon in material applications. In this review, a brief introduction to g-C3N4 is given, the methods used for synthesizing this material with different textural structures and surface morphologies are described, and its physicochemical properties are referred. In addition, four aspects of the applications of g-C3N4 in catalysis are discussed: (1) as a base metal-free catalyst for NO decomposition, (2) as a reference material in differentiating oxygen activation sites for oxidation reactions over supported catalysts, (3) as a functional material to synthesize nanosized metal particles, and (4) as a metal-free catalyst for photocatalysis. The reasons for the use of g-C3N4 for such applications are also given, and we expect that this paper will inspire readers to search for further new applications for this material in catalysis and in other fields.

Polyploidization has provided much genetic variation for plant adaptive evolution, but the mechanisms by which the molecular evolution of polyploid genomes establishes genetic architecture underlying species differentiation are unclear. Brassica is an ideal model to increase knowledge of polyploid evolution. Here we describe a draft genome sequence of Brassica oleracea, comparing it with that of its sister species B. rapa to reveal numerous chromosome rearrangements and asymmetrical gene loss in duplicated genomic blocks, asymmetrical amplification of transposable elements, differential gene co-retention for specific pathways and variation in gene expression, including alternative splicing, among a large number of paralogous and orthologous genes. Genes related to the production of anticancer phytochemicals and morphological variations illustrate consequences of genome duplication and gene divergence, imparting biochemical and morphological variation to B. oleracea. This study provides insights into Brassica genome evolution and will underpin research into the many important crops in this genus. Brassica oleracea is plant species comprising economically important vegetable crops. Here, the authors report the draft genome sequence of B. oleracea and, through a comparative analysis with the closely related B. rapa, reveal insights into Brassicaevolution and divergence of interspecific genomes and intraspecific subgenomes.

Perovskite oxides with formula ABO 3 or A 2 BO 4 are a very important class of functional materials that exhibit a range of stoichiometries and crystal structures. Because of the structural features, they could accommodate around 90% of the metallic natural elements of the Periodic Table that stand solely or partially at the A and/or B positions without destroying the matrix structure, offering a way of correlating solid state chemistry to catalytic properties. Moreover, their high thermal and hydrothermal stability enable them suitable catalytic materials either for gas or solid reactions carried out at high temperatures, or liquid reactions carried out at low temperatures. In this review, we addressed the preparation, characterization, and application of perovskite oxides in heterogeneous catalysis. Preparation is an important issue in catalysis by which materials with desired textural structure and physicochemical property could be achieved; characterization is the way to explore and understand the textural structures and physicochemical properties of the material; however, application reflects how and where the material could be used and what it can solve in practice, which is the ultimate goal of catalysis. This review is organized in five sections: (1) a brief introduction to perovskite oxides, (2) preparation of perovskite oxides with different textural structures and surface morphologies, (3) general characterizations applied to perovskite oxides, (4) application of perovskite oxides in heterogeneous catalysis, and (5) conclusions and perspectives. We expected that the overview on these achievements could lead to research on the nature of catalytic performances of perovskite oxides and finally commercialization of them for industrial use.

Heterogeneous photocatalysis using semiconductors and renewable solar energy has been regarded as one of the most promising processes to alleviate, and even solve, both the world crises of energy supply and environmental pollution. In the past few years, many encouraging achievements have been made in the research area of graphene‐based semiconductor photocatalysts. Among them, CdS/graphene nanocomposites have attracted extensive attention as an important kind of photocatalyst in chemical and material science, due to its superior photocatalytic activity and photostability under visible‐light irradiation. The aim here is to address the enhancement mechanism of the photocatalytic performance of CdS/graphene composite photocatalysts, and systematically summarize recent progress regarding the design and synthesis of CdS/graphene nanocomposites. These nanocomposites are promising for a great diversity of applications in visible‐light photocatalytic fields, including artificial photosynthetic systems (photocatalytic hydrogen production and CO 2 reduction), environmental remediation, and organic photosynthesis. Special attention is given to the photocatalytic hydrogen production and pollutant photodegradation over CdS/graphene nanocomposite photocatalysts. Furthermore, perspectives on CdS/graphene‐based materials are discussed, including the various remaining challenges for large‐scale applications, identifying prospective areas for related research in this field.

A wide variety of commodity chemicals can be produced from the catalytic oxidation of carbohydrates or carbohydrate derived molecules including formic acid, acetic acid, glycolic acid, gluconic acid, glucaric acid, malonic acid, oxalic acid, 2,5-diformylfuran (DFF), 5-hydroxymethyl-2-furancarboxylic acid (HFCA), 5-formyl-2-furancarboxylic acid (FFCA), and 2,5-furandicarboxylic acid (FDCA). This review will highlight the recent research progress in the development of new routes for the production of organic acids and furan compounds via catalytic oxidation reactions. Particular attention will be paid to these one-pot reactions with the requirements of an acidic site and a metal site. For the one-pot transformation of cellobiose or lignocellulose into gluconic acid, these reactions were performed via a one-step strategy using a single catalyst containing an acidic site and a metal site. However, a two-step strategy was adopted for the oxidative transformation of carbohydrates into DFF or FDCA in order to avoid the oxidation of the carbohydrates. The first step was performed for the dehydration of carbohydrates into 5-hydroxylmethylfuran (HMF) in the presence of an acid catalyst, and the second step was performed for the oxidation of HMF into DFF or FDCA with a metal catalyst.

Nitrogen modified reduced graphene oxide (N-RGO) was prepared by a hydrothermal method. The nitrogen modification enhanced its adsorption and catalysis ability. For an initial bisphenol concentration of 0.385 mmol L(-1), the adsorption capacity of N-RGO was evaluated as 1.56 and 1.43 mmol g(-1) for bisphenol A (BPA) and 1.43 mmol g(-1) for bisphenol F (BPF), respectively, both of which were about 1.75 times that (0.90 and 0.84 mmol g(-1)) on N-free RGO. N-RGO could activate persulfate, producing strong oxidizing sulfate radicals. The apparent degradation rate constant of BPA on N-RGO was 0.71 min(-1), being about 700 times that (0.001 min(-1)) on N-free RGO. In mixtures of various phenols, the degradation rate constant of each phenol was linearly increased with its adsorption capacity. A simultaneous use of N-RGO and persulfate yielded fast and efficient removal of bisphenols. The use of N-RGO (120 mg L(-1)) and persulfate (0.6 mmol L(-1)) almost completely removed the added bisphenols (0.385 mmol L(-1)) at pH 6.6 within 17 min. A mechanism study indicated that the adsorption enriched the pollutant, and the catalytically generated sulfate radicals rapidly degrade the adsorbed pollutant, accelerating in turn the adsorption of residual pollutant.

As the rapid growth of social media technologies continues, Cyber-Physical-Social System (CPSS) has been a hot topic in many industrial applications. The use of “microblogging” services, such as Twitter, has rapidly become an influential way to share information. While recent studies have revealed that understanding and modelling microblog user behaviour with massive users’ data in social media are keen to success of many practical applications in CPSS, a key challenge in literatures is that diversity of geography and cultures in social media technologies strongly affect user behaviour and activity. The motivation of this article is to understand differences and similarities between microblogging users from different countries using social media technologies, and to attempt to design a Country-Level Micro-Blog User (CLMB) behaviour and activity model for supporting CPSS applications. We proposed a CLMB model for analysing microblogging user behaviour and their activity across different countries in the CPSS applications. The model has considered three important characteristics of user behaviour in microblogging data, including content of microblogging messages, user emotion index, and user relationship network. We evaluated CLBM model under the collected microblog dataset from 16 countries with the largest number of representative and active users in the world. Experimental results show that (1) for some countries with small population and strong cohesiveness, users pay more attention to social functionalities of microblogging service; (2) for some countries containing mostly large loose social groups, users use microblogging services as a news dissemination platform; (3) users in countries whose social network structure exhibits reciprocity rather than hierarchy will use more linguistic elements to express happiness in microblogging services.

Catalytic synthesis of value-added chemicals from renewable biomass or biomass-derived platform chemicals is an important way to reduce current dependence on fossil-fuel resources. In recent years, 2,5-furandicarboxylic acid (FDCA) has received significant attention due to its wide application in many fields, particularly as a substitute of petrochemical-derived terephthalic acid in the synthesis of useful polymers. Therefore, much effort has been devoted to the catalytic synthesis of FDCA. In this critical review, we will provide an overview of concise and up-to-date methods for the synthesis of FDCA from HMF oxidation or directly from carbohydrates by one-pot reaction, giving special attention to catalytic systems, mechanistic insight, reaction pathway, and catalyst stability. In addition, the one-pot oxidative conversion of carbohydrates into FDCA and the one-pot synthesis of FDCA derivatives are also discussed. It is anticipated that the chemistry detailed in this review will guide researchers to develop effective catalysts for the economical and environmentally friendly synthesis of FDCA in large-scale.

Holey ultrathin g-C3N4 nanosheets (CNHS) with abundant micro-, meso-, and macropores are fabricated by thermal “etching” of bulk g-C3N4. The prepared CNHS possess a unique ultralight characteristic, high specific surface area, more catalytic active sites, and enhanced electron transport ability, leading to a much superior activity in hydrogen generation and photodegradation of pollutant. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is one of the key reactions for producing chemical commodities from biomass and their derivatives. The challenge for this reaction is to develop an efficient catalytic process that can be conducted under mild conditions (room temperature and atmospheric pressure, using oxygen molecules in air as the oxidant) and a recyclable catalyst. Herein we report a photocatalyst of cobalt thioporphyrazine (CoPz) dispersed on g-C 3 N 4 (abbreviated as CoPz/g-C 3 N 4 ), which exhibits excellent catalytic activity toward the selective oxidation of HMF into FDCA under simulated sunlight using oxygen molecules in air as a benign oxidant. For example, an FDCA yield of 96.1% in an aqueous solution at pH = 9.18 is achieved at ambient temperature and air pressure. At lower pH (4.01), the product generated is 2,5-diformylfuran. Hence, it is possible to control the reaction outcome by control of the pH of the reaction system. g-C 3 N 4 itself is not a suitable catalyst for the selective oxidation because under the experimental conditions g-C 3 N 4 generates hydroxyl radicals that initiate processes that oxidize HMF directly to CO 2 and H 2 O. CoPz on the other hand activates O 2 to give singlet oxygen ( 1 O 2 ), which more controllably oxidizes HMF to FDCA albeit at a more moderate yield (36.2%). The strong interaction between the CoPz and g-C 3 N 4 in the CoPz/g-C 3 N 4 catalyst is experimentally evidenced, which not only improves accessibility of the CoPz sites and makes the catalyst recyclable but also disables the hydroxyl radical generation by g-C 3 N 4 and promotes 1 O 2 generation on the CoPz sites, significantly enhancing the catalytic performance. This study demonstrates the potential for efficient non-noble metal photocatalysts for organic transformations driven by sunlight.

Abstract As a prospective next‐generation energy storage solution, lithium–sulfur batteries excel at their economical attractiveness (sulfur abundance) and electrochemical performance (high energy density, ≈2600 Wh kg −1 ). However, their application is impracticable without addressing the following vital issues: i) shuttling effect of lithium polysulfides (LPSs), ii) sluggish redox conversion kinetics of LPSs, iii) large volumetric expansion of S after lithiation (≈80%), and iv) uncontrollable Li dendritic formation. Recently, many strategies have been proposed to solve these issues, which have focused on physical/chemical entrapment of LPSs, catalytic promotion of LPSs conversion and directional regulation of Li plating/stripping. Designing/constructing heterostructured materials is one of the promising approaches to potentially resolve all the above challenges with one material. In this review, the recent advances of heterostructures focused on S cathodes, interlayers and Li anodes are reviewed in detail. First, the fundamental chemistry of Li–S batteries and principles of heterostructures reinforced Li–S batteries are described. Second, the applications of heterostructures in Li–S batteries are discussed comprehensively. Finally, a concise outlook on utilizing the intrinsic and extrinsic properties of heterostructures is delivered, with the aim to provide some inspiration for the design and fabrication of advanced Li–S batteries.

Abstract The development of efficient photocatalysts for the degradation of organic pollutants and production of hydrogen peroxide (H 2 O 2 ) is an attractive two‐in‐one strategy to address environmental remediation concerns and chemical resource demands. Graphitic carbon nitride (g‐C 3 N 4 ) possesses unique electronic and optical properties. However, bulk g‐C 3 N 4 suffers from inefficient sunlight absorption and low carrier mobility. Once exfoliated, ultrathin nanosheets of g‐C 3 N 4 attain much intriguing photocatalytic activity. Herein, a mussel‐inspired strategy is developed to yield silver‐decorated ultrathin g‐C 3 N 4 nanosheets (Ag@U‐g‐C 3 N 4 ‐NS). The optimum Ag@U‐g‐C 3 N 4 ‐NS photocatalyst exhibits enhanced electrochemical properties and excellent performance for the degradation of organic pollutants. Due to the photoformed valence band holes and selective two‐electron reduction of O 2 by the conduction band electrons, it also renders an efficient, economic, and green route to light‐driven H 2 O 2 production with an initial rate of 0.75 × 10 −6 m min −1 . The improved photocatalytic performance is primarily attributed to the large specific surface area of the U‐g‐C 3 N 4 ‐NS layer, the surface plasmon resonance effect induced by Ag nanoparticles, and the cooperative electronic capture properties between Ag and U‐g‐C 3 N 4 ‐NS. Consequently, this unique photocatalyst possesses the extended absorption region, which effectively suppresses the recombination of electron–hole pairs and facilitates the transfer of electrons to participate in photocatalytic reactions.

Black BiOCl with oxygen vacancies was prepared by UV light irradiation with Ar blowing. The as-prepared black BiOCl sample showed 20 times higher visible light photocatalytic activity than white BiOCl for RhB degradation. The trapping experiment showed that the superoxide radical (O(2)(•-)) and holes (h(+)) were the main active species in aqueous solution under visible light irradiation.

Nowadays, photothermal therapy (PTT) utilizing photothermal conversion agents (PTAs) to generate sufficient heat under near-infrared (NIR) light irradiation for tumor ablation has attracted extensive research attention. Despite the great advancement, the therapeutic efficacy of PTT in tumor treatment is still compromised by several obstacles, such as low photothermal conversion efficiency, poor stability of PTAs, inadequate tumor accumulation and cellular uptake, and thermal-resistance of tumors, as well as tumor recurrence and metastasis. In this review, we highlight recent advances in nanomaterials that focus on overcoming the above obstacles and thus enhancing the therapeutic outcome of PTT. PTAs with improved photothermal performance and modification strategies for efficient PTT are summarized, which are further classified into three main types, utilizing activatable PTAs, improving the local concentration of PTAs, and overcoming intrinsic drawbacks of PTT (e.g., heat shock responses). Furthermore, the limitations and challenges of nanomaterials for enhanced PTT are also discussed.

Pure rutile nanorods were synthesized by hydrolysis of TiCl 4 ethanolic solution in water at 50 °C. The assembly of rutile nanorods could be controlled through simply changing the molar ratios of TiCl 4, ethanol, and water, resulting in different superstructures with flower- or urchinlike morphologies. The resulting samples were characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, nitrogen sorption, and UV−vis diffuse reflectance spectrum. A possible mechanism for the growth and assembly of rutile nanorod superstructures was proposed on the basis of characterization results. More importantly, we found that those low temperature synthesized superstructures showed significantly higher photocatalytic activities than commercial photocatalyst P25 on degradation of rhodamine B in water under artificial solar light. This study provides a simple and inexpensive way to prepare high active rutile nanorods superstructures photocatalysts on a large scale.

One of the research hotspots in solar energy conversion is developing photocatalysts for visible-light-driven H2 production. In this study, a ternary CdS@Au/MXene composite was elaborately constructed by a facile in situ self-assembly strategy, where the ultrathin Ti3–xC2Ty nanosheets with characteristic Ti vacancies were employed as a support for core–shell structured CdS@Au nanojunctions. In the presence of 1.0 wt % MXene, merely 0.1 wt % Au helped the composites achieve a high H2-production rate of 5371 μmol·g–1·h–1 under visible-light irradiation, more than 26.6 times higher than that of bare CdS. Such an enhancement was predominantly attributed to the “dual Schottky barriers” formed at the interface of CdS@Au/MXene, which was evidenced by systematic characterizations including X-ray photoelectron spectroscopy and Kelvin probe measurements, in conjunction with density functional theory (DFT) calculations. This work not only highlights the significant role of MXene in reducing the dosage of noble metal cocatalysts for photocatalysis, but also opens avenues to fabricate more MXene-based composites for solar energy conversion and beyond.

Mulberry (Morus alba L.) fruit has a high yield in one fruiting season in many countries, especially in Asia, and a long history of use as an edible fruit and traditional medicine. A great diversity of nutritive compounds such as fatty acids, amino acids, vitamins, minerals, and bioactive compounds, including anthocyanins, rutin, quercetin, chlorogenic acid, and polysaccharides have been found in mulberry fruit depending on the cultivars and maturity stages. Furthermore, the extracts and active components of mulberry fruit have demonstrated numerous biological activities, including antioxidant, neuroprotective, antiatherosclerosis, immunomodulative, antitumor, antihyperglycemic, and hypolipidemic activities in in vitro and in vivo studies, and they have received increasing interest from researchers and pharmaceutical companies. Although some mechanistic studies further substantiate these potential health benefits of mulberry fruit, a need exists to make a better understanding of the roles of these compounds in traditional medicine and the diet. This review provides recent findings regarding the chemical constituents and biological activities of mulberry fruit, which may be useful for stimulating deep research of mulberry fruit and for predicting their uses as important and safe contributors to benefit human health.

This paper investigates the problem of global exponential lag synchronization of a class of switched neural networks with time-varying delays via neural activation function and applications in image encryption. The controller is dependent on the output of the system in the case of packed circuits, since it is hard to measure the inner state of the circuits. Thus, it is critical to design the controller based on the neuron activation function. Comparing the results, in this paper, with the existing ones shows that we improve and generalize the results derived in the previous literature. Several examples are also given to illustrate the effectiveness and potential applications in image encryption.

Abstract Defect‐rich carbon materials possess high gravimetric potassium storage capability due to the abundance of active sites, but their cyclic stability is limited because of the low reversibility of undesirable defects and the deteriorative conductivity. Herein, in situ defect‐selectivity and order‐in‐disorder synergetic engineering in carbon via a self‐template strategy is reported to boost the K + ‐storage capacity, rate capability and cyclic stability simultaneously. The defect‐sites are selectively tuned to realize abundant reversible carbon‐vacancies with the sacrifice of poorly reversible heteroatom‐defects through the persistent gas release during pyrolysis. Meanwhile, nanobubbles generated during the pyrolysis serve as self‐templates to induce the surface atom rearrangement, thus in situ embedding nanographitic networks in the defective domains without serious phase separation, which greatly enhances the intrinsic conductivity. The synergetic structure ensures high concentration of reversible carbon‐vacancies and fast charge‐transfer kinetics simultaneously, leading to high reversible capacity (425 mAh g −1 at 0.05 A g −1 ), high‐rate (237.4 mAh g −1 at 1 A g −1 ), and superior cyclic stability (90.4% capacity retention from cycle 10 to 400 at 0.1 A g −1 ). This work provides a rational and facile strategy to realize the tradeoff between defect‐sites and intrinsic conductivity, and gives deep insights into the mechanism of reversible potassium storage.