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Graphene has promising applications in agriculture and forestry. In the current study, six different concentrations of graphene (0mg/L, 0.01mg/L, 0.10mg/L, 1.00mg/L, 10.00mg/L, and 100.00mg/L) were used to investigate its effect on the growth and development of V. angularis plants in soil culture. The results showed that the group treated with 1.00mg/L graphene (G-1) had significantly increased plant height (19.86%), stem diameter (24.33%), and leaf area (13.69%), compared to the control group (CK). Moreover, all concentrations of graphene had positive effects on the total root length, total root surface area, and the number of root tips of V. angularis. Compared to the CK group, the G-1 group had significantly increased leaf water potential (37.89%), leaf conductivity (2.25%), and SOD, POD, and CAT activities (47.67%, 35.22%, and 199.3%, respectively). The G-1 group also showed improved leaf net photosynthetic rate, chlorophyll content, and soluble sugar content (51.28%, 24.25%, and 38.35%, respectively), compared to the CK group. Additionally, 1.00mg/L graphene led to a 23.88% increase in the podding rate and a 17.04% increase in the yield of V. angularis plants. The rhizosphere soil of V. angularis treated with 1.00mg/L graphene had a 25.14% increase in hydrolyzable nitrogen content and a 66.67% increase in available phosphorus content. RNA-seq data indicated that 1.00mg/L graphene induced the expression of photosynthesis and nitrogen transmembrane transport genes, including ATP synthase subunit b, photosystem I reaction center subunit XI, photosystem I reaction center subunit IV A, ferredoxin, and psbP-like protein 1, as well as genes for photosynthesis antenna proteins, glutamine synthetase, glutamate dehydrogenase 1, cyanate hydratase, protein fluG-like, and NRT1/PTR family, suggesting that graphene promoted the growth and development of V. angularis by enhancing the photosynthesis and nitrogen metabolism processes in V. angularis plants. Our results indicated that a suitable concentration of graphene could significantly promote the growth of V. angularis plants in soil. [ABSTRACT FROM AUTHOR]

In order to investigate the molecular mechanism and transcriptomics of the response of graphene to the roots of Castanopsis hystrix Miq plant. Seedlings were cultivated with 4 groups of graphene solution concentrations of 0, 25, 33 and 50 mg/L, 0 refers to distilled water culture, the root development, gene expression, enrichment pathway and range of differentially expressed genes were analyzed. Compared with 0 group, 25 mg/L graphene solution had the best promoting effect on root development of Castanopsis hystrix seedlings(t=2.86 to 7.80, P<0.05). Transcriptomic data showed that the expression levels of 12 845 genes were changed after 25 mg/L graphene solution was applied to Castanopsis hystrix roots, among which 10 899 genes were up-regulated and 1 946 genes were inhibited. According to the Kyoto encyclopedia of genes and genomes(KEGG) pathway enrichment analysis, the up-regulated genes were mainly enriched in 126 KEGG pathways, and down-regulated genes were enriched in 99 KEGG pathways. In addition, 110 transcription factor genes were differentially expressed and could be classified into 33 different families. Among them, 7 transcription factor family genes, including ERF, WRKY, MYB, NAC, bHLH, TCP and Trihelix were related to root development of Castanopsis hystrix. Analyses of differentially expressed genes related to plant hormone signal transduction pathways showed changes in the expression levels of 7 hormone-related genes, including auxin, cytokinin, gibberellin, ethylene, salicylic acid, brassinosteroid and strigolactone, were closely related to the root growth of Castanopsis hystrix. [ABSTRACT FROM AUTHOR]

Prussian blue analogue (PBA), with a three-dimensional open skeleton and abundant unsaturated surface coordination atoms, attracts extensive research interest in electrochemical energy-related fields due to facile preparation, low cost, and adjustable components. However, it remains a challenge to directly employ PBA as an electrocatalyst for water splitting owing to their poor charge transport ability and electrochemical stability. Herein, the PBA/rGO heterostructure is constructed based on structural engineering. Graphene not only improves the charge transfer efficiency of the compound material but also provides confined growth sites for PBA. Furthermore, the charge transfer interaction between the heterostructure interfaces facilitates the electrocatalytic oxygen evolution reaction of the composite, which is confirmed by the results of the electrochemical measurements. The overpotential of the PBA/rGO material is only 331.5 mV at a current density of 30 mA cm−2 in 1.0 M KOH electrolyte with a small Tafel slope of 57.9 mV dec−1, and the compound material exhibits high durability lasting for 40 h. [ABSTRACT FROM AUTHOR]

Nanopesticides can facilitate controlled release kinetics and efficiently enhance the permeability of active ingredients to reduce the dosage and loss of pesticides. To clarify the synergistic mechanism of graphene–insecticide nanocarriers against cotton bollworm, treatment groups, namely, control, graphene (G), insecticide (lambda-cyhalothrin (Cyh) and cyfluthrin (Cyf)), and graphene-delivered insecticide groups were used to treat the third-instar larvae of cotton bollworm. The variations in phenotypes, namely, the body length, body weight, and mortality of the cotton bollworm, were analyzed. The results show that graphene enhances the insecticidal activity of lambda-cyhalothrin and cyfluthrin against cotton bollworm. The two graphene-delivered insecticides with optimal compositions (3:1) had the strongest inhibitory effects and the highest mortality rates, with the fatality rates for the 3/1 Cyh/G and Cyf/G mixture compositions being 62.91% and 38.89%, respectively. In addition, the 100 μg/mL Cyh/G mixture had the greatest inhibitory effect on cotton bollworm, and it decreased the body length by 1.40 mm, decreased the weight by 1.88 mg, and had a mortality rate of up to 61.85%. The 100 and 150 μg/mL Cyh/G mixtures achieved the same mortality rate as that of lambda-cyhalothrin, thus reducing the use of the insecticide by one-quarter. The graphene-delivered insecticides could effectively destroy the epicuticle spine cells of the cotton bollworm by increasing the permeability and, thus, the toxicity of the insecticides. [ABSTRACT FROM AUTHOR]

Graphene has shown great potential for improving growth of many plants, but its effect on woody plants remains essentially unstudied. In this work, Pinus tabuliformis Carr. bare-rooted seedlings grown outdoors in pots were irrigated with a graphene solution over a concentration range of 0–50 mg/L for six months. Graphene was found to stimulate root growth, with a maximal effect at 25 mg/L. We then investigated root microstructure and carried out transcript profiling of root materials treated with 0 and 25 mg/L graphene. Graphene treatment resulted in plasma-wall separation and destruction of membrane integrity in root cells. More than 50 thousand of differentially expressed genes (DEGs) were obtained by RNA sequencing, among which 6477 could be annotated using other plant databases. The GO enrichment analysis and KEGG pathway analysis of the annotated DEGs indicated that abiotic stress responses, which resemble salt stress, were induced by graphene treatment in roots, while responses to biotic stimuli were inhibited. Numerous metabolic processes and hormone signal transduction pathways were altered by the treatment. The growth promotion effects of graphene may be mediated by encouraging proline synthesis, and suppression of the expression of the auxin response gene SMALL AUXIN UP-REGULATED RNA 41 (SAUR41), PYL genes which encode ABA receptors, and GSK3 homologs. [ABSTRACT FROM AUTHOR]

[Display omitted] We have developed a facile approach to undertake chemical modifications of carbon nanotubes (CNT) and of graphite/graphene via oxidation and surface chemical modification to superhydrophobic nanomaterials. Chemical silane is functionalized to these oxide nanowires forms of carbon-oxygen-silicon chemical bonds via the liquid chemical-vapor-deposition (CVD) technique. After a correlation test of combinations of heating at a set temperature then measuring the surface water contact angle, these two types of materials have been generated showing both having very high thermally stable superhydrophobic nanomaterials. Both of modified CNT and graphene can maintain a superhydrophobic surface at extremely high temperatures, up to 550 and 600 °C, generated from graphene oxide (GO) and surface oxidized carbon nanotubes (CNTO), respectively. Over the critical switchable temperature, the surface switches from superhydrophobic to superhydrophilic immediately; it can be reversed to superhydrophobic by re-coating silane, thereby showing a reversible surface property. The superhydrophobic carbon nanomaterials can rapidly absorb oil either under water or from the surface water. Gaussian DFT calculations for the dissociation energies via different pathways confirm that this system is quite stable, consistent with the thermal test results. [ABSTRACT FROM AUTHOR]

Graphene reportedly exerts positive effects on plant root growth and development, although the corresponding molecular response mechanism remains to be elucidated. Maize seeds were randomly divided into a control and experimental group, and the roots of Zea mays L. seedlings were watered with different concentrations (0–100 mg/L) of graphene to explore the effects and molecular mechanism of graphene on the growth and development of Z. mays L. Upon evaluating root growth indices, 50 mg/L graphene remarkably increased total root length, root volume, and the number of root tips and forks of maize seedlings compared to those of the control group. We observed that the contents of nitrogen and potassium in rhizosphere soil increased following the 50 mg/L graphene treatment. Thereafter, we compared the transcriptome changes in Z. mays roots in response to the 50 mg/L graphene treatment. Transcriptional factor regulation, plant hormone signal transduction, nitrogen and potassium metabolism, as well as secondary metabolism in maize roots subjected to graphene treatment, exhibited significantly upregulated expression, all of which could be related to mechanisms underlying the response to graphene. Based on qPCR validations, we proposed several candidate genes that might have been affected with the graphene treatment of maize roots. The transcriptional profiles presented here provide a foundation for deciphering the mechanism underlying graphene and maize root interaction. [ABSTRACT FROM AUTHOR]

Graphene sheets were prepared by calcination of calcium carbonate with plant leaves under the protection of an argon gas atmosphere. This is an environmentally friendly approach to produce graphene. Calcium carbonate decomposes with the evolution of carbon dioxide at high temperature, which is reduced into graphene by the magnesium from plant leaves. The formation mechanism of graphene is discussed in detail. The synthesized graphene sheets were characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), and Raman spectroscopy. Calcium carbonate and plant leaves are readily available and inexpensive natural resources, and this new methodology can be applied for large‐scale graphene production in industry. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Fe 2 O 3 @Fe 3 O 4 @FeCO 3 /rGO composite was synthesized for the first time by green and simple strategy. • The specific discharge capacities of Fe 2 O 3 @Fe 3 O 4 @FeCO 3 /rGO composite are 868.7 mA g−1 after 200 cycles at 200 mA g−1 and 578.9 mA g−1 after 500 cycles at 2 A g−1.The first reversible capacity is much larger than the theoretical capacity. Fe-based oxides have received tremendous attention owing to its high capacity, low cost, controllable morphology, and immense natural reserves. However, their poor cycle stability hinders practical application. In the present paper, Fe 2 O 3 @Fe 3 O 4 @FeCO 3 /reduced graphene oxide (3-Fe/rGO) composite was synthesized by green and simple strategy. The particle size of 3-Fe heterostructure is reduced and dispersed evenly on the rGO surface. The 3-Fe/rGO composite exhibits excellent electrochemical performance as anode material in Li-ion batteries. The specific discharge capacities of 3-Fe/rGO composite are 868.7 mA g−1 after 200 cycles at 200 mA g−1 and 578.9 mA g−1 after 500 cycles at 2 A/g. The outstanding electrochemical properties arise from the effective synergy existing between FeCO 3 , Fe 3 O 4, Fe 2 O 3, and rGO. Considering the charge transfer and Li+ diffusion, 3-Fe/rGO composite shows excellent properties, indicating that the typical structure and excellent properties of rGO can aid in the coating and buffering of the expansion of 3-Fe heterostructure during the Li+ extraction and insertion processes, reducing the loss of irreversible capacity. Moreover, the conductivity of the electrode is significantly improved. This is an already established method to improve the electrochemical performance of Fe-based oxides, but the present work has added new dimensions to it. [ABSTRACT FROM AUTHOR]

The magnetic and spin transport properties of asymmetric edge-hydrogenated zigzag graphene nanoribbons (ZGNRs) selectively doped with nitrogen atoms were investigated using spin-polarized density functional theory and non-equilibrium Green's function. Results show that the rectifying performance of spin-polarized current with a ratio higher than 10 can be modulated by changing the positions of the nitrogen dopant. Complete spin filtering (100%) and excellent negative differential resistance behaviors were observed in the ZGNR junctions. These doping position-dependent spin transport characteristics were further tested by shifting from the odd-numbered zigzag-shaped C chains ( N) to the even-numbered N in ZGNRs. This study suggests that adopting a suitable nitrogen doping position could be an effective approach to significantly enhance the rectifying behavior of asymmetric edge-hydrogenated ZGNRs, which are promising materials for multifunctional spintronic devices. [ABSTRACT FROM AUTHOR]

In this study, crumpled graphene balls (CGB), a kind of nano-material, was used as an additive to improve the tribological properties of base oil. Nano-magnesium silicate hydroxide (MSH)/CGB composites were prepared by ultrasound-assisted liquid-phase exfoliation. The loading of MSH significantly increased the number of pleats and reduced the lamellar thickness of CGB. Then, in order to improve the compatibility with the base oil, the MSH/CGB composites were decorated with oleic acid and stearic acid to get modified lipophilic composites (ML-MSH/CGB). The ML-MSH/CGB were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, the tribological properties of the ML-MSH/CGB in base oils were investigated using a ball-on-disc setup tribometer. It indicated that the fantastic tribological behavior of the ML-MSH/CGB in base oil may contribute to a smaller and extremely wrinkled laminated structure. Furthermore, the base oil with 0.005 wt% ML-MSH/CGB composites exhibited the best anti-friction effect, and its average friction coefficient, wearing capacity and wear scar diameter were reduced by 25.4%, 22.1% and 16.7%, respectively. The introduction of ML-MSH/CGB composed materials is an excellent strategy to optimize the friction performance of lubricating oil. [ABSTRACT FROM AUTHOR]

• Digital terahertz device with ni/GaN and graphene/GaN dual Schottky barrier junctions. • Metasurface comprising of patterned metal electrodes and a graphene layer. • Modulating the graphene fermi level in a graphene/GaN Schottky barrier junction. • Realization of the three-state logic gate operation for the transmission coefficient of terahertz wave. • Realization of the 1-bit reflected phase coding manipulation and the maximum radar cross section reduction of approximately 11.14 dB. Terahertz technology, III-V group semiconductor devices, and graphene have great potential for broad applications in 6 G wireless communications. A novel digital terahertz device with nickel/GaN and graphene/GaN Schottky barrier junctions was proposed in this study. The patterned metal electrodes of the device, together with the graphene layer, formed a terahertz metasurface. The mechanisms of modulating the fermi level of graphene and the conductivity of the device to manipulate the transmission coefficient and reflected phase of terahertz waves were investigated using numerical calculations. The electrical and optical simulation results theoretically demonstrated that the three-state logic gate operation for the transmission coefficient of terahertz wave at 1.458 THz and the 1-bit reflected phase coding manipulation in 1.51–1.55 THz were realized. In addition, the maximum radar cross section reduction for the reflected wave was approximately 11.14 dB, comparing the designed coding sequences with the metal plate. These functions are mainly implemented by applying an external bias voltage to the device. This study provides a new and feasible strategy for designing digital terahertz manipulation devices. [ABSTRACT FROM AUTHOR]

Well-dispersed graphene oxide (GO) in resin matrix has been found for improving corrosion protection performance of the coatings. In this paper, a new strategy relying on waterborne epoxy curing agent contained GO (GO-WCA) was developed, which was prepared via endcapping, modifying and in-situ grafting process. Wherein, endcapping includes blocking the high-activity hydrogen which is used to modulate curing activity. And the modifying process introduces homologous epoxy segment so as to improve compatibility between curing agent, resin matrix and GO. Attributing to this evolvement of WCA and superior barrier effects of GO, the epoxy coatings cured by GO-WCA exhibit desirable corrosion protection capacity. Besides, the failure mode is discovered as bubbling. This environmentally-friendly waterborne curing agent, only with 4.2 g/L VOC content, is anticipated to become available in diverse waterborne epoxy coatings system with excellent barrier property. [Display omitted] • A strategy of GO-epoxy coating by waterborne curing agent contained GO is presented. • GO-WCA was synthesized by endcapping, modifying and in-situ grafting process. • Modulating curing activity and compatibility promote anticorrosive ability. • The failure mode of GO-containing coatings is discovered as surface powdering. [ABSTRACT FROM AUTHOR]

Thermal management of electronic products and communication equipment is a key bottleneck restricting the integration of products, and high-performance thermal management materials are an effective means to solve this problem. In this study, graphene prepared by liquid phase exfoliation was used as a functional additive material to successfully prepare a graphene high-thermal-conductivity coating material on stainless steel substrates for enhanced cooling performance. The research found that the thermal conductivity of different coating materials with different graphene contents significantly varies, and when the graphene content is 15 %, the thermal conductivity can reach as high as 9.499 W/(m·K), which can rapidly achieve heat dissipation. Considering the actual working conditions of the thermal coating, the comprehensive performance of the coating was tested, and it has excellent corrosion resistance and excellent temperature cycling resistance. Under experimental conditions, after adding the thermal coating to the stainless steel substrate, its cooling effect significantly improved. Compared with uncoated blank samples, the maximum temperature difference during heat transfer under room temperature can reach 11 °C, and the maximum temperature difference under −80 °C can reach 19 °C. This study's coating has potential application prospects in the field of thermal management. [ABSTRACT FROM AUTHOR]

Ni-based amorphous transition metal catalysts have gained considerable research attention owing to their superior alkaline oxygen evolution performance compared to their crystalline counterparts. In this work, we prepared amorphous NiFe/graphene composites via the solvothermal method. By regulating the ratio of components, the composite catalyst exhibited an exceptionally low overpotential of 231 mV at a current density of 10 mA cm−2 and maintained stable catalytic behavior for 100 h at this current density. Electrochemical analysis and differential charge density diagrams revealed the presence of charge transport at the interface of the heterogeneous structure, greatly increasing the intrinsic activity of the material. Additionally, pH dependence on the catalytic activity suggested a decoupled proton-electron transfer (PT/ET) pathway, and chemical deprotonation is identified as the rate-limiting step in the catalytic reaction. These findings provide critical insights and reliable data to facilitate future research on improving the oxygen evolution performance of NiFe-based amorphous catalysts. [ABSTRACT FROM AUTHOR]