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Single‐step conversion of methane to methanol in the gaseous phase is required for high value added application of methane and environmental protection, but it is challenging. Here, direct oxidation of methane to methanol under gaseous condition on iridium promoted Cu/CeO2 catalyst, prepared using a sol‐gel method, is investigated. The addition of iridium can effectively upgrade the redox properties and oxygen storage capacity due to intense metal interaction, stimulating a prominent catalytic performance for methane conversion to methanol on Cu−Ir@CeO2 catalyst. Approximately 26.2 μmol/gcat methanol yield and 68 % methanol selectivity are achieved on the trimetallic 5Cu0.5Ir@CeO2 catalyst at 550 °C in 2 h. Consequences of the analysis of XRD, SEM, HRTEM, Raman, FI‐IR and XPS demonstrate that highly‐dispersed Ir and Cu species are uniformly distributed on CeO2 surface, and partial Cu or Ir atoms replace Ce4+ in CeO2 lattice due to the metal interaction in the colloidal structure, which can impact the catalyst's electronic properties. H2 temperature‐programmed reduction (H2‐TPR) and CH4 temperature‐programmed desorption (CH4‐TPD) results disclose that the unique ternary surface exhibits excellent redox properties and strong adsorption capacity for methane, which can activate the first C−H bond of methane to methyl species, and then react with OH− to form methanol. The good stability in cyclic operation is an additional attribute, rendering this type of catalyst a "front‐runner" in future catalyst development for direct methane‐to‐methanol. This composite catalyst design provides hope for developing ternary metal‐oxide catalysts for functionalization of methane. [ABSTRACT FROM AUTHOR]

Although controlled wrinkling is demonstrated to be a powerful tool for micro/nanofabrication, large‐area fabrication of microarchitecture arrays on curved substrates by surface wrinkling still remains challenging. Inspired by the cortical folding, a facile method for transforming graphene oxide (GO) patterns into multiscale microarchitecture arrays on curved substrates is developed. Mass production of hierarchical GO papillae arrays can be realized by homogeneous compression of patterned GO/rubber bilayers. The reduced GO (rGO) papillae arrays show superhydrophobicity with tunable adhesion to water, enabling good performance in microdroplet manipulation. Besides, the papillae are capable of regulating the formation of microcracks in the rGO films upon stretching. Similar to the mechanical sensing system of spiders, a crack‐based strain sensor with high gauge factor (≈81), good linearity (0–15%), and fast responding speed (<40 ms) is demonstrated. In addition, the strain sensor is capable of detecting and recognizing multiple deformation modes including stretching, poking, and touching. This work reveals novel cortical folding morphology and provides a simple fabrication method for multifunctional hierarchical microarchitectures on curved substrates, which may find applications in biomimetic microstructures, smart wetting surfaces, and wearable electronics. [ABSTRACT FROM AUTHOR]

Tremendous efforts are devoted to developing advanced electrode materials with superior electrochemical performance, high energy density, and high power density for energy storage and conversion. Two‐dimensional (2D) materials, owing to their unique properties, have shown great potential for energy storage. Following the discovery of graphene, a new family of 2D transition metal carbides/nitrides, MXenes, derived from MAX phase precursors, have attracted extensive attention in recent years. The superior physical and chemical properties of MXenes include high mechanical strength, excellent electrical conductivity, multiple possible surface terminations, hydrophilic features, superior specific surface area, and the ability to accommodate intercalants. When applied as electrodes in lithium‐based batteries, MXenes have demonstrated excellent performance. In this progress report, the authors summarize the recent advances of MXenes and MXene‐based composites in terms of synthesis strategies, morphology engineering, physical/chemical properties, and their applications in lithium‐ion batteries and lithium–sulfur batteries. Furthermore, challenges and perspectives for MXenes and MXene‐based composites for lithium‐based energy storage devices are also outlined. MXenes, as a new family of two‐dimensional transition metal carbides and nitrides, have exhibited great potential as advanced electrode materials for lithium‐based batteries. This report summarizes the recent advances of MXenes in terms of synthesis strategies, morphology engineering, physical and chemical properties, and development of lithium‐based batteries. [ABSTRACT FROM AUTHOR]

Three-dimensional metal carbide MXene/reduced graphene oxide hybrid nanosheets are prepared and applied as a cathode host material for lithium-sulfur batteries. The composite cathodes are obtained through a facile and effective two-step liquid-phase impregnation method. Owing to the unique 3 D layer structure and functional 2 D surfaces of MXene and reduced graphene oxide nanosheets for effective trapping of sulfur and lithium polysulfides, the MXene/reduced graphene oxide/sulfur composite cathodes deliver a high initial capacity of 1144.2 mAh g−1 at 0.5 C and a high level of capacity retention of 878.4 mAh g−1 after 300 cycles. It is demonstrated that hybrid metal carbide MXene/reduced graphene oxide nanosheets could be a promising cathode host material for lithium-sulfur batteries. [ABSTRACT FROM AUTHOR]

To restrain the migration and extractability of the antioxidants and improve the dispersion of nanosilica in natural rubber (NR), antioxidant 2- tert-butyl-6-(3- tert-butyl-2-hydroxy-5-methylbenzyl)-4-methyphenyl acrylate (GM) functionalized nanosilica was prepared using antioxidant coupling agent (KH590-GM) as functional modifier, which was first synthesized through thiol-ene reaction between the mercapto group of γ-mercaptopropyl trimethoxysilane (KH590) and the CC double bonds of antioxidant GM. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance confirmed the structure of KH590-GM and GM functionalized nanosilica. Thermogravimetry analysis indicated that the grafting rate of GM functionalized nanosilica reached 13.4%, and the antioxidant had good thermal stability. Scanning electron microscope and mechanical properties measurement showed GM functionalized nanosilica was dispersed uniformly in NR vulcanizates, and helpful for the increase of the tensile strength and tensile stress of NR vulcanizates. Based on the study of the antioxidative behavior and extraction resistance of the NR vulcanizates, it was found that in contrast to NR vulcanizates with GM, the ageing coefficient and oxidation induction time of that with GM functionalized nanosilica increased to 0.66 and 39 min from 0.58 and 30 min, respectively. Furthermore, the NR vulcanizates with GM functionalized nanosilica also exhibited excellent extraction resistance. POLYM. COMPOS., 38:1241-1247, 2017. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Per-2,3-acetyl-β-cyclodextrin is first synthesized by selective modification and used as core molecule for preparing a star-shaped macromolecular antioxidant (β-CD-DBHMP) via a two-step method. β-CD-DBHMP is characterized by 1H-NMR, MALDI-TOF MS, and TGA. The performance of β-CD-DBHMP as antioxidant for natural rubber is determined by OIT and accelerated thermal aging test, and its extraction resistance is also investigated. The results show that β-CD-DBHMP with a Mn of 4.03 × 103 g · mol−1 is successfully obtained, and it possesses high thermal stability with an initial weight loss temperature of 290 °C. Moreover, β-CD-DBHMP is superior to DBHMP for the stabilization of NR against thermal oxidation, and exhibits better extraction resistance. Its possible antioxidative mechanism is also discussed. [ABSTRACT FROM AUTHOR]

Nonprecious metal single‐atom materials have attracted extensive attention in the field of electrocatalysis due to their low cost, high reactivity, high selectivity, and high atomic utilization. However, the high surface energy of a single atom causes agglomeration during preparation and catalytic measurement, resulting in damage to the catalytic sites. The strong interaction between substrate and monoatoms is the key factor to prevent the aggregation of individual metal atoms, and the geometry and electronic structure of the catalysts can be adjusted to optimize the catalytic activity. Due to the hierarchically pores, high specific surface area, and defect effect, nitrogen‐doped porous carbon (NPC) has been widely studied as an ideal nonprecious metal single‐atom support, which synergistically enhance the electrocatalytic performance toward oxygen reduction reaction, oxygen evolution reaction, hydrogen evolution reaction, carbon dioxide reduction reaction, and nitrogen reduction reaction with non‐noble metal single atoms. This review summarizes the controllable synthesis, characterization, theoretical calculation, and application of M (M = Co, Fe, Ni, Cu, Zn, Mo, etc.) single atoms on nitrogen‐doped porous carbon. Finally, the future development and challenges of nitrogen‐doped porous carbon supported nonprecious metal single‐atom electrocatalysts for practical commercialization are concluded. [ABSTRACT FROM AUTHOR]

Template‐free, highly efficient, and large‐area construction of complex multiscale architectures is still a great challenge for microfabrications. Inspired by the hierarchical micropapillae on the superhydrophobic surface of natural rose petals, here, a facile 3D shrinking method is reported to build a graphene oxide (GO) papillae array. Circular GO speckles with a gradient of thickness are deposited on an inflated latex balloon through the water‐evaporation‐driven assembly of GO nanosheets, which then shrink into hierarchical papillae under compressive stresses upon deflation. The fluoroalkylsilane modified GO papillae array exhibits a combined performance of strong superhydrophobicity (CA > 170°), tunable adhesive force (39.2–129.4 µN), and ultralarge liquid capacity (25 µL). The wetting states (Wenzel, Cassie‐I, and Cassie‐Baxter), the adhesive forces, and the liquid capacities all can be tuned by varying the buckling topography (microwrinkle or microfold), the papillae number (3, 4, 6, or 7), and the array arrangement (triangle, square, or hexagon). For one single papillae, the highest adhesive force and the highest liquid capacity incresed to a record breaking value of 26.5 µN and 4.2 µL, respectively, which are promising for programmable manipulations of microdroplets and relevant for multistep microreactions. Inspired by the multiscale papillae on the rose petal, a template‐free 3D‐shrinking method is developed. The obtained bioinspired papillae array exhibits strong superhydrophobicity (CA > 170°), ultralarge liquid capacity (25 µL), and tunable adhesive force (39.2–129.4 µN). Its application for programmable transfer of microdroplets and for multistep microreaction platforms is demonstrated. [ABSTRACT FROM AUTHOR]