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Potential applications of previously synthesized pillared graphene oxide frameworks with phenyldiboronic acid linkers in the field of the adsorption and separation of polar protic and aprotic liquid solvents have been systematically explored using grand canonical Monte Carlo simulations. Particular attention was initially paid to the adsorption of pure liquid water, methanol, and dimethyl sulfoxide. The results obtained a significant increase in the isosteric heat of adsorption at low uptake in the case of dimethyl sulfoxide, which is about 17.9 and 26.8 kJ/mol higher than the values corresponding to methanol and water adsorption. These findings indicated that from a thermodynamic point of view, these pillared graphene oxide frameworks could be used in the separation of dimethyl sulfoxide–water liquid mixtures. Systematic grand canonical Monte Carlo simulations were then subsequently performed for dimethyl sulfoxide–water mixtures, with a low dimethyl sulfoxide concentration. The calculated values of the separation selectivity indicate that these materials could have potential applications in the separation of these mixed liquid solvents. Molecular dynamics simulations performed for a representative adsorbed mixture have revealed a substantial slowing down of the dynamics under confinement, particularly in the case of the hydrogen bonds formed between water and dimethyl sulfoxide. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is a two-dimensional, mechanically strong, and chemically tunable material for separations. Elucidating GO–ion–water interactions at the molecular scale is highly important for predictive understanding of separation systems. However, direct observations of the nanometer region by GO surfaces under operando conditions are not trivial. Therefore, thin films of GO at the air/water interface can be used as model systems. With this approach, we study the effects of alkali metal ions on water organization near graphene oxide films at the air/water interface using vibrational sum frequency generation (SFG) spectroscopy. We also use an arachidic acid Langmuir monolayer as a benchmark for a pure carboxylic acid surface. Theoretical modeling of the concentration-dependent sum frequency signal from graphene oxide and arachidic acid surfaces reveals that the adsorption of monovalent ions is mainly controlled by the carboxylic acid groups on graphene oxide. An in-depth analysis of sum frequency spectra reveals at least three distinct water populations with different hydrogen bonding strengths. The origin of each population can be identified from concentration dependent variations of their SFG signal. Interestingly, an interfacial water structure seemed mostly insensitive to the character of the alkali cation, in contrast to similar studies conducted at the silica/water interface. However, we observed an ion-specific effect with lithium, whose strong hydration prevented direct interactions with the graphene oxide film. [ABSTRACT FROM AUTHOR]

As water pollution is increasing due to industrialization, there is a high demand for easy-processing photocatalytic materials to clean wastewater. Here, the improvement in the photocatalytic dye degradation effect of graphene oxide (GO) surfaces, made of ultra-sonication assisted modified Hummer's method, is demonstrated with increasing alumina (Al2O3) concentration in the range of 4–30 wt. %. Scanning electron microscopy and x-ray diffraction results suggest a gradual increment in crystalline Al2O3 nanoparticles (NPs) by reducing GO, in good agreement with the first-principles calculations. Moreover, x-ray photoelectron spectroscopy reveals the appearance of oxygenated functional groups with increasing Al2O3 concentration, leading to the formation of defect-rich GO as demonstrated by Raman spectroscopy. Ultraviolet-visible spectroscopy further reflects a maximum reduction in the optical bandgap from 1.88 to 1.56 eV up to a concentration of 15 wt. % Al2O3. Interestingly, the methylene blue degradation efficiency of GO under ultraviolet irradiation is also found to be improved from 45% to 64% with 15 wt. % Al2O3, whereas the formation of Al2O3 NPs in the range of 100–300 nm with 30 wt. % Al2O3 is found to be detrimental for photocatalytic activity. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated red light (∼ 660 nm) and magnetic field dependence of impedance across (100 − x)% ZnO(zinc oxide)– x % rGO(reduced graphene oxide)/La 0.7 Sr 0.3 MnO 3 (LSMO)/ITO (x =0,0.6,0.8,100) heterostructure devices. Field-induced scattering due to the spin filter effect and spin polarized tunneling (SPT) have been extracted from the zinc oxide–reduced graphene oxide nanocomposite/LSMO space charge region (ZnO–rGO/LSMO SCR) and the LSMO active region of the devices, respectively. Higher SPT leads to higher LSMO SCR scattering across the devices. Devices with higher rGO contents could not be fitted with two RC circuits as resistance values because the two phenomena are incomparable with each other. Light-induced scattering has been observed at the ZnO–rGO nanocomposite active region and ZnO–rGO/LSMO SCR of the devices. For composite devices with x =0.8 and 0.6, higher photocarrier generation at ZnO–rGO nanocomposite active layer leads to enhanced scattering at LSMO SCR with light illumination. Light-dependent scattering at both regions, however, follows almost same decreasing trend for bare devices with x =0, 100. The decreasing trend of light-dependent scattering for ZnO/LSMO/ITO and rGO/LSMO/ITO bare devices suddenly gets reversed and, eventually, follows an increasing trend at magnetic field ambiance of 0.5 and 1 kOe, respectively. The LSMO SCRs of the bare devices got enhanced with the field, leading to a light-dependent response similar to composite devices at the higher field. [ABSTRACT FROM AUTHOR]

This study investigated the improvement of the electro-optical properties of a liquid crystal (LC) cell fabricated through brush coating using graphene oxide (GO) doping. The physical deformation of the surface was analyzed using atomic force microscopy. The size of the groove increased as the GO dopant concentration increased, but the direction of the groove along the brush direction was maintained. X-ray photoelectron spectroscopy analysis confirmed that the number of C–C and O–Sn bonds increased as the GO concentration increased. Since the van der Waals force on the surface increases as the number of O–metal bonds increases, we were able to determine why the anchoring energy of the LC alignment layer increased. This was confirmed by residual DC voltage and anchoring energy measurements that were later performed. As the GO concentration increased, the width of the hysteresis curve decreased, indicating that the residual DC voltage decreased. Additionally, the 15% GO-doped sample exhibited a significant increase in its anchoring energy up to 1.34 × 10−3 J/m2, which is similar to that of rubbed polyimide. It also secured a high level of electro-optical properties and demonstrated potential as a next-generation thin-film display despite being produced via a simple brush-coating process. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) ultra-thin materials are more crucial than their bulk counterparts for the covalent functionalization of their surface owing to atomic thinness, large surface-to-volume ratio, and high reactivity of surface atoms having unoccupied orbitals. Since the surface of a 2D material is composed of atoms having unoccupied orbitals, covalent functionalization enables one to improve or precisely modify the properties of the ultra-thin materials. Chemical functionalization of 2D materials not only modifies their intrinsic properties but also makes them adapted for nanotechnology applications. Such engineered materials have been used in many different applications with their improved properties. In the present Perspective, we begin with a brief history of functionalization followed by the introduction of functionalized 2D materials. Our Perspective is composed of the following sections: the applications areas of 2D graphene and graphene oxide crystals, transition metal dichalcogenides, and in-plane anisotropic black phosphorus, all of which have been widely used in different nanotechnology applications. Finally, our Perspectives on the future directions of applications of functionalized 2D materials are given. The present Perspective sheds light on the current progress in nanotechnological applications of engineered 2D materials through surface functionalization. [ABSTRACT FROM AUTHOR]

The development of composite materials with excellent thermal conductivity is attracting extensive attention to meet the increasing heat concentration challenges in both power and electronic equipment. Previous strategies for improving the thermal conductivities usually accompanied by the cost of mechanical strength. Herein, we propose a new strategy for developing both mechanically strong and thermally conductive composite films. The aramid nanofibers (ANF) are well prepared with introducing Ag nanoflakes and graphene oxide (GO) via vacuum-assisted filtration and hot-pressing treatment. Results indicate the synergistic effects of low dimension materials have resulted in a tightly arranged phonon network construction. The in-plane thermal conductivity of the prepared ANF/Ag/GO film reaches 9.84 W m−1 K−1, about 371% higher than that of pure ANF. Meanwhile, the strong hydrogen bond formed between the functional group of GO and the amide group of ANFs plays a synergistic strengthening and toughening role at the complex interface, and the tensile strength reaches 231 MPa. We believe that these findings shed some light on the design and fabrication of multifunctional materials for thermal management applications. [ABSTRACT FROM AUTHOR]

The rational synergy of chemical composition and spatial nanostructures plays an important role in high-performance electromagnetic wave (EMW) absorption materials. Here, reduced graphene oxide (RGO) hollow microspheres loaded with CoNi alloy nanoparticles (Air@RGO/CoNi) were constructed by a facile water-in-oil emulsification route followed by high-temperature thermal treatment. The crystal structure, composition, microstructure, and magnetic properties of Air@RGO/CoNi were characterized by XRD, XPS, TEM, and VSM, respectively. The results demonstrated that the as-obtained Air@RGO/CoNi composites showed a uniform spherical morphology with a remarkably hollow structure. Impressively, nano-CoNi particles were compactly and uniformly distributed on the surface of RGO. Benefiting from the unique structure and compositional merits, the optimized Air@RGO/CoNi hollow microspheres exhibit superior (EMW) absorption performance. The minimum reflection loss (RLmin) value reached up to −56.16 dB at 13.67 GHz with a thin thickness of 2.55 mm and the widest effective absorption bandwidth (RL values are below −10 dB) covered 8.65 GHz (9.15–17.8 GHz) with a thinner thickness of 2.4 mm. Furthermore, possible EMW attenuation mechanisms had been proposed. Given these outstanding findings, we believe the as-fabricated Air@RGO/CoNi hollow microspheres can be promising candidates as highly microwave absorption materials with thin thickness, wide absorption bandwidth, and high absorption capacity. [ABSTRACT FROM AUTHOR]

Absolute kinetics for reactions of C2H2 with a series of ∼60 individual carbon nanoparticles (NPs) from graphite, graphene, graphene oxide, carbon black, diamond, and nano-onion feedstocks were measured for temperatures (TNP) ranging from 1200 to 1700 K. All the NPs were observed to gain mass by carbon addition under conditions that varied with feedstock but with large variations in initial growth rate. Long reaction periods were studied to allow the evolution of growth rates over time to be observed. Diamond NPs were found to passivate against C2H2 addition if heated above ∼1400 K, and the highly variable initial reactivity for carbon nano-onions was found to depend on the presence of non-onion-structure surface carbon. For graphitic and carbon black NPs, three distinct growth modes were observed, correlated with the initial NP mass (Minitial). Smallest graphitic and carbon black NPs, with masses <∼25 MDa, initially grew rapidly but also passivated quickly after adding <4% of Minitial. NPs in the 20–50 MDa range also passivated but only after multiple waves of fast growth separated by periods of low reactivity, with up to ∼11% total mass gain before passivation. The largest carbon black and graphitic NPs, with Minitial >50 MDa, grew rapidly and continuously, adding up to ∼300% of Minitial with no sign of rate slowing as long as C2H2 was present. The efficiencies for C2H2 addition and etching by O2 are strongly correlated, but the correlation changes as the NPs passivate. Growth and passivation mechanisms are discussed. [ABSTRACT FROM AUTHOR]

Structure-directing synthesis, such as by the template method, allows us to control the porous structure and morphological properties of solid-state materials. Traditionally, molecules and zero-, one-, and three-dimensional materials have been used as structure-directing agents and templates. Recently, two-dimensional materials (e.g., graphene oxide and graphitic carbon nitride) have been investigated for their use in the synthesis of nanostructured materials. In this study, we used carbon nitride as the structure-directing agent for controlling SiO2 and cupric oxide (CuO) formation in the development of porous CuO–SiO2 nanocomposites via the calcination of a mixture of Cu2+, polyhedral oligomeric silsesquioxane (POSS), and carbon nitride to solve the problems with CuO (e.g., porosity control and low efficiency per weight relative to light materials). Further, we investigated the formation factors of the nanocomposites using comparative experiments to understand the roles of Cu2+, POSS, and carbon nitride. During calcination, carbon nitride induced the formation of SiO2, which supported CuO; the effect of Cu species removed carbon nitride. Subsequently, porous CuO–SiO2 nanocomposites were constructed. The constructed CuO–SiO2 nanocomposites presented a unique morphology (i.e., a fluffy structure), high surface area, and narrow optical band gap. The demonstrated method may pave the way for the design of CuO composite materials and the development of their application as adsorbents and catalysts. [ABSTRACT FROM AUTHOR]

Hydrazine borane (HB) has been considered to be an excellent medium for hydrogen storage, but the development of efficient catalysts for controllable and complete hydrolytic dehydrogenation of HB remains a severe challenge. In this study, a novel catalyst consisting of Ni0.6Pt0.4 nanoparticles supported on phosphorus-doped reduced graphene oxide (P-rGO) is readily obtained via a simple co-reduction method and serves as a highly efficient and stable catalyst toward the complete hydrolytic dehydrogenation of HB. Compared with Ni0.6Pt0.4/rGO, the as-prepared Ni0.6Pt0.4/P-rGO catalyst exhibits much higher catalytic activity for HB dehydrogenation, providing a total turnover frequency (TOF) value of 2419.4 h−1 at 323 K, which surpasses that of the majority of reported catalysts. Meanwhile, it also exhibits lower activation energy (Ea) and better recycle stability. The reason for the outstanding catalytic performance of Ni0.6Pt0.4/P-rGO could be attributed to the combined influence of small particle sizes, the enhanced synergistic effects of NiPt nanoparticles and the P-rGO substrate, the electronic interaction between Ni and Pt, and the NaOH promotion effect. This work provides an innovative approach to construct highly efficient and robust catalyst systems using simple and controllable methods. [ABSTRACT FROM AUTHOR]

Here, ternary layer hydroxide (NiCoFe-LDH) nanosheets have been grafted in situ onto graphene oxide (GO) using a one-pot hydrothermal method to obtain NiCoFe-LDH/GO for the fabrication of a non-enzymatic glucose sensor with high stability. SEM analysis shows that ternary LDHs with a nanosheet layer structure grow on GO at an angle with less stacking, thus imparting NiCoFe-LDH/GO with a large specific surface area (112.32 m2 g−1) that exposes more active sites. The results of cyclic voltammetry (CV) and chronoamperometry (CA) studies show that NiCoFe-LDH/GO/GCE displays a wide linear detection range of 0.005–7.54 mM, a sensitivity of 196.18 μA cm−2 mM−1, and a low detection limit of 0.41 μM (S/N = 3). In particular, NiCoFe-LDH/GO/GCE has high stability, that is, it still holds 90.2% of its initial value even after 90 days. Meanwhile, the study results demonstrate that the NiCoFe-LDH/GO/GCE electrode is suitable for the detection of glucose in artificial saliva, and it also reveals a good recovery ranging from 95.6% to 105.5% in actual saliva. Therefore, NiCoFe-LDH/GO is anticipated to be an ideal sensing material for the creation of noninvasive enzyme-free glucose sensors. [ABSTRACT FROM AUTHOR]

The potential of polyoxometalates (POMs) as alternatives to noble metal-based bifunctional electrocatalysts for air electrode, i.e., for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), was analyzed herein. Five POMs containing transition metal (Mn, Fe, Co, Ni, or Cu) were prepared and combined with reduced graphene oxide (rGO). Kenning structure of POMs with nanolamellae-like morphology and multi-layered graphene sheets of rGO were confirmed by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, transmission electron microscopy and Raman spectroscopy analysis. Different POM:rGO ratios were tested to optimize the composition, and a ratio of 1:5 Ni-POM:rGO was found to be the most electrocatalytically active for OER (Tafel slope as low as 42 mV dec−1, overpotential at 10 mA cm−2 of 354 mV and current density at 400 mV overpotential as high as 83.4 mA cm−2), notably better than IrO 2. As for ORR, Co-POM/rGO carried the lowest Tafel slope of 165 mV dec−1, half-wave potential of 0.711 V and a mixed 2- and 4-electron ORR mechanism. Moreover, these non-precious metal electrocatalysts showed stability in alkaline media with no change in their structure. [Display omitted] • Synergistic effect of transition metal-POM and rGO enhances activity for OER/ORR. • Co-POM/rGO and Ni-POM/rGO outperform IrO 2 as benchmark electrocatalyst for OER. • The price of the catalyst per generated current is lower than in the case of costly IrO 2. • Co-POM/rGO demonstrates the best bifunctional character for ORR/OER. [ABSTRACT FROM AUTHOR]

Three‐dimensional multi‐axial warp knitted (3D MWK) reinforced composites are important components of advanced structural composites. The interfacial bonding between fiber and matrix is key to achieving high mechanical properties. In this work, graphene oxide (GO) and poly(oxypropylene) diamines (D400) were grafted on glass fiber (GF) multi‐axial warp knitted (MWK) fabrics to construct a "flexible‐rigid" structure. The surface morphologies of GF were characterized by SEM and EDS. Then, 3D MWK‐reinforced composites were prepared based on four kinds of modified fabrics using the VARTM method. The in‐plane compression properties were obtained at different high temperatures and their failure modes were analyzed. The strain–stress curves showed that the composites exhibited brittle fracture modes. D400 and GO‐modified multi‐scale composites exhibited outstanding compression properties. The strength of the related composited was improved by 55.78%, 76.78%, 52.19%, and 56.78% compared to that of desized composite at 30°C, 60°C, 120°C and 150°C, respectively. The damage to D400‐GO modified and D400 modified composites was the most serious, where shear fracture modes were obvious in addition to layer debonding features. This protocol provides a potential strategy to manufacture of D400 and GO‐modified hierarchical reinforced composites. Highlights: The modified 3D MWK glass fabrics based on poly(oxypropylene) diamines (D400) and graphene oxide (GO) were prepared.The compressive properties of 3D desized, D400‐, D400‐GO‐, and GO‐MWK fabrics reinforced epoxy composites were obtained and analyzed at different temperatures of 30°C, 60°C, 120°C, and 150°C.The failure mechanisms of 3D desized, D400‐, D400‐GO‐, and GO‐MWK fabrics reinforced epoxy composites at different temperatures were analyzed. [ABSTRACT FROM AUTHOR]

Lead pollution in water has risen globally, due to industrialization and globalization. In this study, this problem was addressed by preparing poly (lactic acid) (PLA)/poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV)/graphene oxide (GO) composites and addressing their effectiveness in absorbing water, and adsorbing Pb(II) ions in water. In water absorption studies, increasing the GO content to above 1 wt.% (3 and 5 wt.%) resulted in the degradation of the composites. All blends, and composites with 1 wt.% GO loading showed good water intake properties, with the composites having the highest. Pb (II) ion intake analyses showed that all the materials adsorb Pb(II) ions significantly in 24 h contact time, but the composites with 1 wt.% GO loadings adsorbed the greatest (81.3%–86.5%). For the effect of pH on adsorption, the adsorption of Pb(II) ions increased with an increase in pH from acidic to basic. This was attributed to the abundance of hydroxyl ions in basic media, that will not compete with Pb(II) ions for adsorption sites. Conclusions were that the 49.5/49.5/1 w/w PLA/PHBV/GO composite was the most optimal adsorbent of Pb(II). This composite could be used in industrial water purification processes like membranes, to remove lead ions from water while conserving the environment. Highlights: Melt mixed PLA/PHBV/GO composites for removing lead ions from water.1 wt.% GO contents in the composites sufficiently absorbed water.3 and 5 wt.% GO contents resulted in the hydrolytic degradation of composites.Contact time is directly proportional to the degree of lead ion adsorption.Basic pH media resulted in the optimal adsorption of lead ions from water. [ABSTRACT FROM AUTHOR]

Toward high‐strength bio‐based polyamide 56 (PA56) fiber, we first in situ precipitate graphene oxide (GO), adipic acid and 1,5‐pentanodiamine together by reaction crystallization in ethanal to obtain PA56 salt/GO particles with well dispersed GO, then prepare PA56/GO nanocomposite with PA56 salt/GO via solvent‐free polymerization including solid‐state prepolycondensation and melt polycondensation. Finally, PA56/GO nanocomposite fiber is prepared by extrusion drawing. With 0.2 wt% GO, the tensile strength of PA56/GO fiber reaches 1050 MPa, which is 3.3 times that of pure PA56 fiber. Furtherly, we add PA56/GO with high GO content to commercial PA56 to prepare the hybrid fiber, of which the tensile strength reaches 1248 MPa. The great improvement is mainly due to the good dispersion of GO in the whole process, which increases the heterogeneous nucleation in favor of higher and oriented PA56 crystallization. Highlights: Bio‐based PA56/GO nanocomposite fiber with 1.2 GPa strength has been prepared.PA56 salt/GO particles with well‐dispersed GO are in situ precipitated.Solvent‐free polymerization is used instead of solution melt polymerization.Well‐dispersed GO results in high and oriented crystallinity of PA56/GO fiber.Tensile strength of PA56/GO fiber is 2.3 times that of commercial PA56 fiber. [ABSTRACT FROM AUTHOR]

Highlights The urgent need for sustainable energy storage solutions has spurred research on high‐performance and cost‐effective energy storage technologies. Supercapacitors (SCs) show great potential due to their capacity to provide significant capacitance, energy and power density. This study focused on the enhancement of electrically conductive reduced Graphene Oxide (rGO) reinforced with polyaniline (PANI) composites to fabricate the supercapacitors. Various characterization techniques, including SEM, EDAX, Raman spectroscopy, FTIR, PXRD, TGA, BET, and CV were employed for the examination of the materials. The findings demonstrate that the rGO/PANI composite displayed nanostructured layers characterized by flaky leaf‐like structures, a trigonal crystal system, and a notable specific capacitance of 410 Fg−1, along with capacitance retention rate of 85 after completion of 1000 cycles. This composite showcases outstanding electrochemical performance leads to the promising material to use in SCs manufacturing. Electrode showed pseudocapacitive behavior, capacitance of 392 F/g. PXRD pattern confirmed presence of benzenoid and quinonoid groups. BET analysis showed surface area of 16.850 m2/g, porous nature indicated. Electrode displayed good reversibility, with a‐b value of 0.6. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) are increasingly becoming a potential treatment approach for bone injuries due to the multi-lineage differentiation potential, ability to recognize damaged tissue sites and secrete bioactive factors that can enhance tissue repair. The aim of this work was to improve osteogenesis of carbon fibers reinforced polyetheretherketone (CF/PEEK) implants through bone marrow mesenchymal stem cells (BMSCs)-based therapy. Moreover, bioactive graphene oxide (GO) was introduced into CF/PEEK by grafting GO onto CF to boost the osteogenic efficiency of BMSCs. Subsequently, CF/PEEK was implanted into the symmetrical skull defect models of SD rats. Then in vivo biosafety and osteogenesis were evaluated. The results indicated that surface wettability of CF/PEEK was effectively improved by GO, which was beneficial for the adhesion of BMSCs. The pathological tissue sections stained with H&E showed no significant pathological change in the main organs including heart, liver, spleen, lung and kidney, which indicated no acute systemic toxicity. Furthermore, bone mineralization deposition rate of CF/PEEK containing GO was 2.2 times that of pure CF/PEEK. The X-ray test showed that the surface of CF/PEEK containing GO was obviously covered by more newly formed bone tissue than pure CF/PEEK after 8 weeks of implantation. This work demonstrated that GO effectively enhanced surface bioactivity of CF/PEEK and assisted BMSCs in accelerating differentiation into bone tissue, providing a feasible strategy for improving osteogenesis of PEEK and CF/PEEK. [ABSTRACT FROM AUTHOR]

Through loading photo-reduced graphene oxide (rGO), photocatalytic hydrogen evolution activity of CH(NH 2) 2 PbBr 3 is greatly elevated from 74.5 µmol/h to 386.7 µmol/h (100 mg, AM1.5G, 100 mW cm−2), making CH(NH 2) 2 PbBr 3 /rGO composite an efficient photocatalyst in aqueous HBr solution saturated with CH(NH 2) 2 PbBr 3 perovskite. [Display omitted] Solar hydrobromic acid (HBr) splitting using perovskite photocatalysts provides an attractive avenue to store solar energy into hydrogen (H 2) and bromine (Br 2), while an efficient photocatalytic system is still demanded. As for the semiconductor photocatalyst, formamidinium perovskites show some superiorities in structural stability, light adsorption and charge dynamics compared to their methylammonium counterparts, which are fitter for the photocatalysis process. Herein, the composite of formamidinium lead bromide perovskite (FAPbBr 3) with reduced graphene oxide (rGO) is prepared using a facile photoreduction method. Under simulated sunlight irradiation (AM1.5G, 100 mW cm−2), this FAPbBr 3 /rGO composite (100 mg) demonstrates a noteworthy enhancement in photocatalytic H 2 evolution activity of 386.7 μmol h−1, and it exhibits a notable stability with no significant decrease after 50 h of repeated tests. The single particle PL (photoluminescence) microscope is employed to study the charge dynamics, revealing that rGO in the composite effectively promotes the carrier separation. This work provides a highly efficient and stable photocatalyst for HBr splitting, and offers an effective modification strategy on lead bromide perovskites. [ABSTRACT FROM AUTHOR]

In this study, ceramic materials of Mg(Ti0.99Sn0.01)O3 were synthesized and decorated on reduced graphene oxide, forming a nanocomposite of rGO/Mg(Ti0.99Sn0.01)O3 (rGO/MTS001). The successful synthesis results were confirmed by XRD, UV–vis analysis, FT-IR, and SEM-EDS. The MTS001 has a flower-like morphology from scanning electron microscopy (SEM) analysis, and the nanocomposites of rGO/MTS001 showed MTS001 particles decorated on the rGO's surface. The electrochemical performance of rGO/MTS001 and MTS001 was investigated by determining the specific capacitance obtained in 1 M H2SO4 solution by cyclic voltammetry, followed by galvanostatic charge–discharge analysis using a three-electrode setup. The rGO/MTS001 achieved a specific capacitance of 361.97 F g‒1, compared to MTS001 (194.90 F g‒1). The capacitance retention of rGO/MTS001 nanocomposite also depicted excellent cyclic stability of 95.72% after 5000 cycles at a current density of 0.1 A g‒1. The result showed that the nanocomposite of ceramics with graphene materials has a potential for high-performance supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

The removal of organic effluents from polluted water is a significant concern. Photodegradation of organic effluents can be performed using different photocatalysts. For this purpose, herein nickel cobaltite (NC) was prepared via the auto moisturization route and nickel sulfide (NS) via a hydrothermal approach. rGO-based nanocomposite (NC/NS/rGO) was synthesized using an ultrasonication approach. The as-prepared nanocatalysts were employed for bromophenol blue and diclofenac degradation. The outcomes of colored (bromophenol blue) effluent degradation by NC, NS, NC/NS, and NC/NS/rGO was found to be 42.65 %, 33.92 %, 56.19 %, and 81.44 %, respectively. The % degradation of diclofenac by NC/NS and NC/NS/rGO was realized to be 44.05 % and 65.98 %, respectively. NC/NS/rGO showed greater catalytic activity than other fabricated nanocatalysts due to the combined effect of nickel cobaltite and nickel sulfide and the existence of rGO. The rGO layers exhibited immense and active sites for the degradation reaction. A radical trapping analysis was performed to investigate the participation of active species in the photocatalytic reaction. [ABSTRACT FROM AUTHOR]

A novel fiber reinforced cementitious composites was developed by incorporating microencapsulated phase change materials (PCMs) and nanographene oxide (NGO) to enhance the composites' thermal properties without compromising the compressive strength. Regarding the thermo-mechanical properties, with the addition of NGO, while mechanical properties improve, thermal mass increases and the heat storage ability of the produced composite material enhances. In this situation; it can be interpreted that it will be possible to benefit more from the energy stored by PCMs, as the energy required to change the temperature of the unit mass of the material will decrease. The environmental impact assessment has also revealed that CO 2 emissions from production increase with the use of PCMs. However, it has been determined that the addition of NGOs will make a positive contribution to the life cycle, as CO 2 emissions resulting from cement will decrease. In conclusion, a novel fiber reinforced composite with enhanced thermal and mechanical properties by combining PCMs and NGO has shown a great potential for environmentally friendly buildings with the integration of structure, energy conservation and long term durability. [ABSTRACT FROM AUTHOR]

Reduced Graphene Oxide (rGO)-reinforced MgAl 2 O 4 spinel composite was successfully synthesized by a solid-state powder route mechanism via high-energy planetary ball milling of corresponding metal oxide precursors followed by a high-temperature single-stage sintering process. The effect of rGO on the homogeneity, phase development, morphology, chemical composition, rate of formation of spinel, and cation anti-site formation of the composites was methodically investigated. For comparison, a stoichiometric non-reinforced MgAl 2 O 4 spinel was also synthesized. The addition of 0.2 wt% and 0.4 wt% of rGO as reinforcement increased the homogeneity of the ball-milled composite powder, with Polydispersity Index (PDI) values of 0.19 and 0.15 respectively, as compared to 0.24 obtained in non-reinforced spinel composite. The X-ray diffraction pattern and IR spectrum of 1650 °C sintered composites confirmed the formation of highly crystalline phases with spinel structure. The microstructural analysis revealed that the addition of rGO led to a reduction in porosity and improved the process of sintering. Calorimetric studies showed that spinelization started to occur at 858 °C and 880 °C for 0.2 wt% and 0.4 wt% rGO-reinforced composites respectively, which was faster than non-reinforced composite. 27Al solid-sate nuclear magnetic resonance (SS-NMR) analysis depicted that ceramic composite reinforced with rGO exhibited lesser inversion parameter of 0.09 (for 0.2 wt% rGO) and 0.055 (for 0.4 wt% rGO), as compared to 0.145 obtained in non-reinforced composite, indicating lesser cation anti-sites formation in rGO-reinforced spinel composite. [ABSTRACT FROM AUTHOR]

In this work, a series of alumina coating reduced graphene oxide (RGO@Al 2 O 3) composites with core-shell structure was synthesized by the atomic layer deposition (ALD) method. The alumina (Al 2 O 3) thickness of the RGO@Al 2 O 3 could be controlled by changing the number of ALD cycles. The microstructure, high-temperature resistance, and microwave absorbing properties of the composites were investigated in detail. The composite could provide excellent high-temperature resistance and microwave absorbing properties. The composite started decomposition at 620 °C. The maximum reflection loss value of the composite obtained by applying 200 Al 2 O 3 deposition cycles is −14.2 dB at 15.7 GHz, and its effective absorption bandwidth reaches 5.0 GHz (13.0–18.0 GHz). The results show that the RGO@Al 2 O 3 composite has the potential application in high-temperature microwave absorbing fields, due to excellent high-temperature resistance, reflection loss, and effective absorption bandwidth. [ABSTRACT FROM AUTHOR]

Nanolubricants are dispersions of nanomaterials in a lubricating base. In this work, polyethylene glycol (PEG) was modified with graphene (G) and copper oxide (CuO) to obtain a nanolubricant (NL). The nanolubricants were prepared and their physicochemical and tribological properties were evaluated. The base and the nanomaterials were evaluated using Fourier-transform infrared spectrometry (FTIR), field-emission scanning electron microscopy coupled with energy dispersive spectroscopy (FE-SEM-EDS), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Raman spectroscopy (Raman). Rheology and Tribology tests were also performed using a four-ball tester according to ASTM 2783. The results showed that nanolubricants have a Newtonian behavior and the viscosity was not significantly modified with the additives. The weld point obtained for the nanolubricants was 160 kgf. In addition, when compared to the PEG, the size of the wear scars was reduced by 9.6% (PEG with 0.01% w/w of CuO) and 35.3% (PEG with 0.05% w/w of CuO and G). The wear protection provided by G is higher than the protection provided by CuO. When the two additives were added, the wear protection increased, and a synergistic effect was observed. Two protection mechanisms were observed in the SEM: rolling bearing/ball effect (CuO) and deposition of G at valleys and peaks of the surface roughness. This article shows novel results related to a laboratory evaluation of nanolubricants in a typical tribological test (four-ball). A novel result was observed in the synergistic effect between the two additives (graphene and CuO) determined by the wear mechanism observed in the tests. [ABSTRACT FROM AUTHOR]

Adding pour point depressant is an important method to solve the poor low temperature rheology of waxy crude oil. Although the traditional polymer pour point depressant has good improvement effect, it has some problems, such as poor resistance to repeated heating and shear. Therefore, nanoparticles are widely used to improve the rheology of crude oil. Although nanoparticles have a certain influence on the improvement of low-temperature rheology, and nanocomposite particles have better improvement effect than single polymer pour point depressant, no one has combed and summarized the influence mechanism of nanoparticles and their composites. This paper introduces three kinds of nanoparticles and their composite materials, briefly describes the performance of the influence of various nanoparticles and their composite particles on the rheology of waxy crude oil, and analyzes the mechanism of their influence on the rheology of waxy crude oil. The analysis of this paper shows that the influence and mechanism of individual nanoparticles on the rheology of crude oil are different due to their different properties. All nanocomposite particles meet the heterogeneous nucleation mechanism, and the polar group of nanocomposite particles is an important factor affecting the effect of nanocomposite particles. Carbon based nanoparticles, especially graphene oxide, promise important research prospect. [ABSTRACT FROM AUTHOR]

This study describes an easy and cheap inkjet printing method for producing a paper-based gas sensor consisting of a composite film made of graphene oxide and poly(3,4-ethylenedioxythiophene) and poly(styrenesulfonate) (PEDOT:PSS). A glossy paper substrate is an inkjet printed with ink made by dispersing graphene oxide in a PEDOT:PSS conducting polymer solution to test its ability to detect ammonia (NH3) at ambient temperature. The presence of few-layer graphene oxide in the PEDOT:PSS copolymer and the existence of π-π interactions between graphene oxide and PEDOT:PSS are confirmed by Fourier transform infrared spectroscopy, UV–Visible spectrophotometer, and X-ray diffraction. In a small concentration range of 1–100 ppm at ambient temperature, the ink-jet printed graphene oxide-PEDOT:PSS gas sensor displays strong responsiveness and good selectivity to NH3. The study found that NH4 is a strong donor in the ammonia gas produced by a bubble system of ammonia water, with NH4 molecules being ideal candidates for molecular doping of graphene. The H2O molecule can facilitate quick desorption by converting NH3 to NH4. The interaction between graphene oxide and NH3 molecules is weak. The attained gas-sensing performance may be attributed to the increased specific surface area of graphene oxide and enhanced interactions between the sensing film and NH3 molecules via π and lone pair electron network. The NH3-sensing mechanisms of the flexible printed gas sensor are based on the competitive interaction of ammonia on the sensor, adsorption and dissociate ionization on the sensor surface. [ABSTRACT FROM AUTHOR]

Highlights Polymer composites with heat resistance, good thermal conductivity, and insulation properties can meet the special needs of electronics and electrical appliances. In this work, graphene oxide (GO) and carbon nanotubes (CNTs) are coated by polydopamine (PDA). 4,4′‐diaminodiphenyl ether (ODA), pyromellitic dianhydride (PMDA), and 4,4′‐oxydiphthalic anhydride (ODPA) in‐situ polymerize to prepare poly(amide acid) (PAA) containing thermally conductive yet insulating fillers (PDA@GO, PDA@CNTs). As the concentration of fillers in PI composites increases, the thermal conductivity rises, but the insulation property decreases. Keeping the filler content constant and varying the ratio of PDA@GO and PDA@CNTs, the thermal conductivity increases and then decreases. When PDA@GO and PDA@CNTs have a mass ratio of 10:1, the significant synergistic effect affects the thermal conductivity. The PI/PG10C1–25 sample has a thermal conductivity of 1.46 W/(m·K), which is 6.9 times greater than the pure PI. Additionally, the volume resistivity, dielectric permittivity, and dielectric loss (100 kHz) of PI/PG10C1–25 are 2.8 × 1013 Ω cm, 5.4 and 0.28, respectively. The heat resistance of PI composites is almost the same as that of pure PI. Given these outstanding attributes, the developed PI composites offer vast applications in many fields. Synergistic PDA@GO and PDA@CNTs (10:1) optimize thermal conductivity. PI/PG10C1–25 achieves 6.9 times higher thermal conductivity than pure PI. Volume resistivity of PI/PG10C1–25 reaches 2.8 × 1013 Ω·cm. Dielectric permittivity of PI/PG10C1–25 reaches 5.4 at 100 kHz. Developed PI composites maintain excellent heat resistance. [ABSTRACT FROM AUTHOR]

Magnetic hybrids with exceptional magnetic and optical properties have emerged as promising materials for diverse applications. In the present work, magnetite (Fe3O4)-functionalized graphene oxide (GO) was synthesized using a facile in situ coprecipitation synthesis method. The in situ formation of Fe3O4 nanoparticles in the presence of GO led to the self-assembly of GO sheets into nanoscrolls. The structural and morphological properties of the nanoscrolls were evaluated. The optical properties were studied using UV-Vis absorbance spectroscopy. Magnetic response assessment by vibrating sample magnetometer confirmed that Fe3O4–GONS had a good superparamagnetic property with maximum saturation magnetization of 54.4 (± 0.5) emu gm−1. The superparamagnetic blocking temperature of the FGO 1 sample was evaluated by temperature-dependent magnetization studies. The in vitro cytotoxicity of the prepared nanocomposites was investigated using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay on a fibroblast L929 cell line. The cell viability studies reveal that all the Fe3O4–GO nanohybrids exhibit excellent cell viability (above 80%) compared to that of the control sample. It is worth noting that the magnetic functionalization of GO with Fe3O4 and the scroll structure is a way to enhance the biocompatibility. This work suggests the promise of using multifunctional Fe3O4–GO hybrids in biomedical applications. [ABSTRACT FROM AUTHOR]

In order to prepare self-standing and flexible slow neutron reflectors made of graphite fluoride (GF) with high contents of (C2F)n structural phase, graphite foils of different thicknesses were used as starting materials for gas (F2)/solid fluorination. The maximal interlayer distance of GF was obtained with this phase thanks to the stacking sequence FCCF/FCCF; this is mandatory for the efficient reflection of slow neutrons. 71 and 77% of the (C2F)n phase were achieved for graphite foils with thicknesses of 1.0 and 0.1 mm, respectively. The interlayer distances were 8.6 Å as expected. The fluorination conditions (static mode, a long duration of 24 h, annealing in pure F2 gas for 24 h, and temperatures in the 390–460 °C range) were adapted to large pieces of graphite foils (7 × 7 cm2) in order to both avoid exfoliation and achieve a homogeneous dispersion of fluorine atoms. This process was also efficient for thinner (0.01 mm thick) graphitized graphene oxide foil. 56% of the (C2F)n phase and an interlayer of 8.6 Å were achieved for this foil when fluorination was performed at 430 °C. Whatever the nature and the thickness of the foil, their flexibilities are maintained. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) has become one of the emerging and important sole photocatalyst nanomaterials in recent years due to its exceptional/tunable optoelectronic properties, multifunctionality, and eco‐friendly nature. However, challenges remain in tuning surface chemistry, tailoring the band gap, developing doping strategies, and understanding the sole photocatalytic mechanism. This contribution investigated the synthesis of GO via the improved Hummers method by varying the ratio of the oxidizing agents (K2Cr2O7:KMnO4), as well as modifications by nitrogen (N) and boron (B) doping in view of its applications in photocatalytic degradation of organic dye pollutants. Furthermore, changes in surface chemistry, optical, compositional, morphological, and structural properties are investigated to understand the photocatalytic mechanism. The synthesized GO showed a broad spectrum of light absorption with a tunable band gap of 2.4–4.3 eV and exhibited more than 91% degradation of methylene blue dye under direct sunlight. However, the photocatalytic activity decreased after N and B doping attributed to reduced oxygen‐containing functional groups, low surface area, and dopants‐induced bonding configurations within the GO structure. This study provides a new insight into replacing metallic semiconductor photocatalysts with highly affordable, environmentally friendly, and potent metal‐free GO photocatalysts. [ABSTRACT FROM AUTHOR]

This study demonstrates the effective copolymerization of N‐Vinyl pyrrolidone and methyl methacrylate using reduced graphene oxide adorned with copper oxide nanoparticles (CuO‐rGO) acting as a catalyst when exposed to blue LED irradiation to generate random copolymer hybrid system of P(NVP‐co‐MMA/CuO‐rGO). We investigated the effects of this copolymer hybrid system of P(NVP‐co‐MMA/CuO‐rGO) on the mechanical, thermal and antibacterial properties of epoxy (DEGBA‐DETDA) composite. By employing two different concentrations of CuO nanoparticle, we assessed the reinforcement capability of the synthesized copolymer‐nanoparticle hybrid within an epoxy matrix. We observed that the composite sample comprising P(NVP‐co‐MMA/CuO‐rGO), having 0.5% of CuO‐rGO (Cu002) with respect to the epoxy concentration resulted in significant enhancements in fracture toughness. Further mechanical properties and thermal properties of the composite samples were studied using DMA, DSC and TGA. Microstructural properties and Mechanisms of toughening are elucidated through the examination of SEM images depicting the fracture surfaces. Moreover, the hybrid composites exhibited notable antibacterial activity against both E. coli and S. aureus compared to control. These findings highlight the copolymer hybrid P(NVP‐co‐MMA/CuO‐rGO) system's role as a multifunctional filler, enhancing epoxy composites' durability, functionality, and antibacterial performance. Our work advances the field of composites by showcasing the customized use of nanoparticle‐enhanced copolymers to improve material properties, providing valuable insights for the development of next‐generation composite materials. Highlights: Achieved novel copolymerization of N‐Vinyl pyrrolidone and methyl methacrylate.CuO‐rGO successfully facilitates P(NVP‐co‐MMA/CuO‐rGO) nanocomposite formation.P(NVP‐co‐MMA/CuO‐rGO) nanocomposite proved as an effective filler for epoxy.P(NVP‐co‐MMA/CuO‐rGO) reinforced epoxy enhances toughness by 143% over neat epoxyReinforced epoxy showed better efficacy against E. coli & S. aureus versus control. [ABSTRACT FROM AUTHOR]

To tackle the challenge of filler agglomeration and low interfacial bonding strength during manufacturing filled polymer dielectric nanocomposites containing graphene oxide (GO) nanosheets, the author proposed an interface design strategy based on the synergistic hybridization of ionic liquid (IL) modification and different dimensional fillers. GO nanosheets were functionalized by IL, and then polyvinylidene fluoride (PVDF) dielectric nanocomposites (GO‐g‐IL/PVDF) were prepared and evaluated. Based on this, hydroxylated barium titanate BT‐OH@GO‐g‐IL/PVDF ternary nanocomposites were further prepared. A comprehensive analysis of the morphology, mechanical, thermal, electrical, and dielectric properties of the PVDF dielectric nanocomposites was systematically conducted. The results showed that IL was successfully grafted on GO, benefiting an increase in the filler dispersion and interfacial bonding strength. GO‐g‐IL also promoted β‐crystal formation of PVDF and increment of crystallinity. DSC test further revealed that the inclusion of BT‐OH@GO‐g‐IL as dielectric nanofillers promoted the formation of multiple crystal types in PVDF and accelerated the crystallization process. The incorporation of GO‐g‐IL facilitated the formation of localized conductive networks within the PVDF matrix, leading to enhanced electronic displacement polarization and an improved dielectric constant. The dielectric constants of the GO‐g‐IL/PVDF composites containing 2% and 8% of GO‐g‐IL were measured to be 24.28 and 78.46, which were found to be 2.6 and 8.4 times higher than that of pure PVDF. However, the dielectric loss also increased sharply at high nanofiller loading. The dielectric constant and loss of the BT‐OH@GO‐g‐IL/PVDF nanocomposites were found to be 40.32 and 0.38, with a content of 2% for GO‐g‐IL and 20% for BT‐OH. Highlights: A facile interface design strategy based on ionic liquid (IL) integrating GO nanosheets and hydroxylated barium titanate (BT‐OH) to form BT‐OH@GO‐g‐IL compounding nanofiller has been proposed.PVDF dielectric nanocomposites containing BT‐OH@GO‐g‐IL compounding nanofiller were systematically investigated and compared.The effects of interfacial interactions between BT‐OH@GO‐g‐IL and PVDF contribute to the uniform dispersion and comprehensive property improvements of PVDF dielectric nanocomposites.This work provides a novel strategy for the fabrication of PVDF dielectric nanocomposites, inspiring the research and development of PVDF in the energy storage applications areas in the future. [ABSTRACT FROM AUTHOR]

In response to the escalating environmental impact of fossil fuels, there's a growing demand for clean energy solutions, particularly efficient metal-air batteries. Metal-air batteries are promising for energy storage, boasting abundant materials and low cost. However, their efficiency is hindered by slow oxygen reduction and evolution reactions. Synthesizing effective and stable oxygen electrocatalysts is crucial for enhancing battery performance. Here, this work used a simple solvothermal method to synthesize Iron–Cobalt metal-organic framework (FeCo-MOF), Manganese–Iron–Cobalt metal-organic framework (MnFeCo-MOF), and their composites with (1, 3, and 5) wt% rGO and characterized via using XRD, SEM, FTIR, and Raman spectroscopy. Electrochemical testing was conducted in 1 M KOH solution for both OER and ORR. The 3 wt% rGO MnFeCo-MOF shown the lowest overpotential of 54 mV at 10 mA/cm2 and the lowest Tafel slope of 63.4 mV/dec, with highest current density of 79.42 mA/cm2 at 25 mV/s scan rate for OER indicating excellent electrocatalytic activity superior to already reported in literature due to synergistic effect of Mn, Fe, Co, and rGO facilitating rapid electron transfer and more active sites. The 3 wt% rGO MnFeCo-MOF exhibited the halfwave potential of 0.74 V for ORR showing excellent activity comparable to commercial catalysts Pt/C. The lower potential gap ΔE 0.66 V from the overall combined plot of OER/ORR shows efficient and stable bifunctional activity of the 3 wt% rGO MnFeCo-MOF. These exceptional electrocatalytic properties pave the way for future advancements in metal-air batteries. [Display omitted] • FeCo-MOF, MnFeCo-MOF, and their composites with rGO were synthesized solvothermaly at 120 °C. • 3 wt% rGO MnFeCo-MOF showed lowest TAFEL slope 63.4 mV/dec and overpotential of 54 mV at 10 mA/cm2 for OER. • 3 wt% rGO MnFeCo-MOF for ORR has a halfwave potential of 0.74 V. • Exhibited excellent stability studied via chronopotentiometry experiment. • Synergic effect among rGO and Mn, Fe, Co MOF active sites. [ABSTRACT FROM AUTHOR]

The pursuit of efficient and sustainable energy conversion has driven significant research on the development of advanced electrode materials for photoelectrochemical (PEC) water splitting. In this study, we present a novel composite material composed of Z-type multifaceted CuSe and FeSe 2 binary metal selenide nanoparticles (NPs) decorated on a graphene oxide (GO) matrix as an active electrode material for high-performance PEC water splitting applications. The catalytic activity of copper-based catalysts is enhanced by the inclusion of iron (Fe) and selenium (Se), as these elements facilitate the creation of more robust covalent connections between the metal and anion. Further, the presence of an amalgamation of GO, which possesses a substantial surface area and excellent electrical conductivity, enhances oxygen evolution reaction (OER) efficiency. The electrode (i.e., CuSe–FeSe 2 @GO) demonstrated an exceptionally low overpotential of 16.3 mV at a current density of 10 mmA cm−2, a modest Tafel slope of 58.3 mV dec−1, and a current density of 26.04 mA cm−2 in an alkaline aqueous solution under 1 Sun. The detection of superoxide radicals (O2−•) suggests the potential formation of Z-type heterojunctions between CuSe and FeSe 2 NPs. Thus, this research offers a novel approach for the fabrication of resource-rich, economical, and highly active Cu-based catalysts for the OER. [Display omitted] • CuSe and FeSe 2 on GO matrix create novel material for efficient EC & PEC water splitting. • The synergy of CuSe, FeSe 2 , and GO enhances catalysis, forming covalent connections, improving OER efficiency. • CuSe–FeSe 2 @GO electrode exhibits high performance in alkaline solutions under 1 Sun. • The composite provides Cu-based catalysts for sustainable OER, achieving a current density of 26.04 mA cm−2. • The CuSe–FeSe 2 @GO composite shows a remarkable 42.14% improvement in OER efficiency over FeSe 2 @GO. [ABSTRACT FROM AUTHOR]

High‐performance microwave absorption (MA) materials are attracting growing attention to solve the expanded electromagnetic interference problems. Herein, zeolitic imidazolate organic frameworks (MOF)‐67 (ZIF‐67) are grown in situ on the sheet of graphene oxide (GO) through the coordination of Co2+ with oxygen functional groups. Through carbonization in an inert atmosphere, Co@carbon polyhedra (Co@CP)‐decorated reduced GO composites (Co@CP‐rGO) with a large number of heterogeneous interfaces are successfully obtained. The composites demonstrate excellent MA performance. With a filler loading of 10 wt%, the optimal minimum reflection loss (RL) of the composite can reach −54.6 dB. More importantly, the composites with thickness of 3.5 and 2.5 mm show the effective absorption bandwidth (RL < −10 dB) of 4.75 GHz (8.18–12.93 GHz) and 6.56 GHz (11.44–18 GHz), fully covering the X‐ and Ku‐band. It is proposed that the synergistic effect of multiple dielectric loss, magnetic loss, reflections and scattering contributes to the high MA performance. [ABSTRACT FROM AUTHOR]

This study presents a novel environmentally friendly approach for synthesizing a water-compatible superhydrophilic molecularly imprinted resin on graphene oxide (SMIR/PGO). In the design of SMIR/PGO, dopamine (DA) serves a dual role: (1) self-polymerizing on the GO surface to form polydopamine, which acts as an environmentally friendly bridge for covalently grafting SMIR and (2) acting as green hydrophilic monomers, replacing traditional phenolic monomers to obtain SMIR. The dual role of DA eliminates the need for tedious steps such as separation, washing, and drying of intermediate materials, facilitating a simple one-pot synthesis. Additionally, hexamethylenetetramine (HMTA) replaces the traditional crosslinker formaldehyde, thereby avoiding direct contact with the carcinogenic formaldehyde. The NH3 produced by HMTA decomposition acts as a catalyst, obviating the need for additional catalysts in the synthesis of SMIR/PGO. This one-pot synthesis occurs in an aqueous matrix and entirely avoids the use of organic solvents, aligning with green chemistry principles and ensuring compatibility with aqueous solutions. Consequently, SMIR/PGO combines the high specific surface area of GO, the multifunctionality of polydopamine, and the excellent water compatibility and high selectivity of SMIR. This combination provides multiple adsorption interactions to achieve selective extraction of chlorogenic acid in the aqueous matrix. This environmentally friendly synthetic strategy offers an efficient means of designing superhydrophilic molecularly imprinted materials with exceptional recognition and adsorption capabilities in aqueous environments. [ABSTRACT FROM AUTHOR]

In this work, Ru nanoparticles doped with Mo on reduced graphene oxide (RuMo/rGO) are prepared through synchronous reduction of RuCl3, MoCl5, and graphene oxide. The compositions, morphologies, and structures of the as-prepared RuMo/rGO composites are fully characterized. Their catalytic properties in oxidative cleavage of β-O-4 linkages in lignin model compounds and lignin are explored. It is illustrated that with O2 as the oxidant RuMo/rGO shows overall better catalytic performance in the oxidative cleavage of β-O-4 linkages than the catalysts, such as Ru/rGO and RuCo/rGO, reported in our previous work. The catalytic mechanism is elaborated through experiments and density functional theory (DFT) calculation. Pronouncedly, we show that the as-doped Mo can effectively boost the molecular oxygen activation process and the adsorption of β-O-4 model compounds on the Ru nanoparticle surface on rGO, and thus enhance the catalytic activity. It is demonstrated meanwhile that RuMo/rGO can catalyze the depolymerization of organosolv birch lignin yielding 17.1% aromatic compounds under relatively mild conditions (100 °C, 0.3 MPa O2, 12 h, pH = 12). [ABSTRACT FROM AUTHOR]

TThe use of ion-imprinted polymers (IIPs) to target hazardous heavy metal ions is an effective solution for addressing water pollution by recognizing and adsorbing specific metal cations. Although dual-template IIPs can offer enhanced efficiency as opposed to single-template IIPs due to their ability for simultaneous adsorption of ions, they have been rarely investigated. This work aimed to develop a new dual-template IIP-based adsorbent for the uptaking of Cd(II) and Ni(II) from aqueous solutions, simultaneously. Surface imprinting technology was employed to synthesize this IIP using modified graphene oxide (GO) as a substrate matrix, acrylamide (AAm) as a monomer, and ethylene glycol dimethylacrylate (EGDMA) as a cross-linker. The prepared GO-IIP was characterized using FT-IR spectroscopy, SEM, EDX, and TGA, and the results were compared with those of the non-ion imprinted polymer (GO-NIP) as the control sample to enhance the understanding of functional groups, morphological changes, elemental composition, and thermal behavior, respectively. By carrying out batch experiments to examine the key parameters affecting the adsorption process, it was found that adsorption took place rapidly within the first 15 min. The maximum adsorption of Cd(II) and Ni(II) occurred at an initial concentration of 300 mg L-1, a temperature of 25 1C, a pH of 6, and an equilibrium contact time of 3 h. The equilibrium experiments demonstrated a strong fitting with the Langmuir isotherm model, revealing maximum monolayer adsorption capacities of 188.67 mg g-1 for Cd(II) and 153.13 mg g-1 for Ni(II). A comparison of the maximum adsorption capacities between GO-IIP and GO-NIP exhibited significant differences [78.12 mg g-1 for Cd(II) and 61.35 mg g-1 for Ni(II)], highlighting the superior performance of the imprinted adsorbent for ion removal. Moreover, the adsorption was spontaneous, exothermic, and physio-chemical in nature based on the calculated thermodynamic parameters. [ABSTRACT FROM AUTHOR]

In response to the global climate change and energy crisis, electrocatalytic CO2 reduction reaction (ECR) is regarded as one of the potential ways to simultaneously reach the CO2 conversion and obtain various value‐added products. Currently, several challenges remain for the in‐depth understanding of ECR from fundamentals, including ambiguous structure‐activity relationships, uncontrollable catalytic selectivity, and complex reaction mechanisms. Compared to traditional metal nanoparticle‐based materials, atomically dispersed catalysts (ADCs) have aroused significant interest owing to their maximal atomic utilization and simplified site configuration, offering a superior platform for discussing the structure‐activity relationships during ECR. Especially, adjacent metal atomic pairs (AAPs) within ADCs are gradually emphasized as a novel concept to follow various synergistic reaction mechanisms during ECR. Herein, for the first time a broad concept of AAPs and analyzed how AAPs within ADCs reached the synergistic effect during ECR is summarized. In view of the synergistic reaction mechanisms varying on different supports, three types of supports are illustrated (containing graphene model, functional porous frameworks, and metals and oxides), aiming to help scholars with more insights in broadening the feasible synergistic reaction mechanisms on AAPs within ADCs. [ABSTRACT FROM AUTHOR]

Highlights This research aims to investigate the effect of reduced graphene oxide (rGO) on the kinetics of addition vulcanization in polydimethylsiloxane (PDMS) elastomers. For this purpose, the synthesis of graphene oxide (GO) and silane‐grafted GO followed by chemical reduction of particles was conducted to prepare rGOs with different surface chemistry. Particles were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, x‐ray diffraction, scanning electron microscopy, and energy‐dispersive x‐ray analysis. Composites of PDMS containing these particles were prepared by solution mixing, and vulcanization of composites was investigated using differential scanning calorimetry. Results showed that the rate and degree of vulcanization reaction increase up to a critical concentration of particles and then decrease afterward. This behavior was attributed to the catalytic effect of chemical groups on the surface of rGOs, whereas the reverse behavior above the critical concentration was correlated to the immobilization of trapped rubber in the network of particles. Grafting graphene oxide by a long alkyl‐chain silane covered these chemical groups, suppressed the catalytic effect, improved the dispersion of particles, and shifted the critical concentration lower. The critical concentration was correlated to the electrical percolation threshold of particles and confirmed by the solvent swelling method. It was also shown that rGO can itself act as the catalyst for the vulcanization of PDMS with no need for platinum. As the dynamic‐mechanical‐thermal analysis showed, the PDMS composites containing 0.75 wt% of particles did not vulcanize properly. However, composites containing fewer particles were vulcanized. Reduced graphene oxide affects additional vulcanization of PDMS. Below a critical loading, rGO accelerates vulcanization by a catalytic effect. Above critical loading, rGO decelerates vulcanization by a networking effect. Surface groups of rGO control catalytic and networking mechanisms. Silane modification of rGO affects interfacial behavior, thus critical loading. [ABSTRACT FROM AUTHOR]