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The development of core-shell structures has been in great demand recently owing to their integrated functionalities. However, the progress in reliable coating of porous semiconductors remains unproductive. Here, we have demonstrated a confined interfacial monomicelle assembly method for controlled coating of ordered single-layered mesoporous TiO2. The coating method can be well controlled with tunable coated layers, mesopore size, and switchable coated surfaces. The resulting mesoporous TiO2 exhibit excellent electrochemical properties as a sodium-ion anode, which is attributed to their unique mesostructures associated with accessible high surface area and ultrathin layers. Such accurately designed mesoporous core-shell nanostructures are expected to provide a useful platform to produce numerous delicate core-shell nanostructures with integrated functionalities and mesoporosities for potential applications, such as catalysts, sensors, energy storage, and energy conversion. - 2019 Elsevier Inc.Mesoporous core-shell nanostructures have recently been receiving extensive scientific interest; however, reliable approaches for coating mesoporous materials still remain exciting challenges, except for amorphous silica. We report, for the first time, a confined interfacial monomicelle assembly method for controlled coating of anatase TiO2 with single-layered ordered mesopores on diverse surfaces, opening up the area of coating ordered mesoporous crystalline materials that possess mesopores originating from self-assembled surfactant instead of accumulated nanocrystals. This facile and repeatable methodology relies on the solvent-confinement effect of glycerol during the assembly process and monomicelle hydrogel preformation by selective evaporation of double-solvent precursors. This assembly process shows precise controllability and great versatility, endowing the coated TiO2 layers with highly tunable thickness, mesopore size, and switchable coated surfaces. The ultrathin monolayered mesopores of such mesoporous TiO2 shells, in combination with their high surface area and highly crystalline nature, afford them excellent rate capability and superior cyclability for sodium-ion storage. - 2019 Elsevier Inc.We have demonstrated a confined interfacial monomicelle assembly approach for accurately coating ordered monolayered TiO2 mesopores on diverse surfaces. By regulating the synthetic conditions, the coated mesoporous TiO2 layers can be well controlled with desired thickness, mesopore size, and switchable coated surfaces. The resulting monolayered mesoporous TiO2 exhibit excellent sodium-storage properties. This unique mesoporous TiO2 coating strategy affords great potential in constructing multicomponent nanostructures with mesoporosities for advanced technologies. - 2019 Elsevier Inc. This work is supported by the State Key Basic Research Program of China ( 2017YFA0207303 ), the National Natural Science Foundation of China ( 21733003 ), the Shanghai Leading Academic Discipline Project ( B108 ), and the Science and Technology Commission of Shanghai Municipality ( 17JC1400100 ). K.L. acknowledges the financial support by the China Scholarship Council ( 201806100112 ). A.E. acknowledges Qatar University under GCC Co-Fund Program grant GCC-2017-001 . Scopus

High capacity transition metal oxides have attracted much attention as potential sodium-ion batteries (SIBs) anodes. However, the fast capacity fading greatly limits their practical applications. In this study, highly crystallized mesoporous Fe3O4 nanoparticles encapsulated in the hollow nitrogen-doped carbon nanospheres (denoted as HCM-Fe3O4@void@N-C) have been synthesized and then explored as anode materials for SIBs. The resultant HCM-Fe3O4@void@N-C nanospheres possess a uniform particle size of ~ 180 nm with highly crystallized mesoporous Fe3O4 cores (~ 100 nm in diameter), a large surface area of ~ 250 m2 g−1 and a nitrogen-doped carbon shell (~ 7.6 wt%). Notably, a high discharge capacity of 372 mA h g−1 is obtained after the first five cycles at 160 mA g−1, which can gradually increase and be maintained at an ultrahigh specific capacity of 522 mA h g−1 even after 800 cycles. Besides, remarkable rate performance with a capacity of 196 mA h g−1 at a current density of 1200 mA g–1 and a high Coulombic efficiency (~ 100%) are obtained. Such good performance can be attributed to the unique yolk-shell nanostructure with a high crystallized mesoporous Fe3O4 core, a high conductive N-doped carbon shell, and a suitable void space, paving a new way to design and synthesize high-performance anode materials for SIBs.

Mesoporous TiO2 nanomaterials have been investigated for decades; however, most endeavors have been focused on the exploration of their potentials in various applications, and the fundamental research for preparing mesoporous TiO2 in a highly controllable manner remains unfruitful. Herein, we report a facile pressure-driven oriented assembly approach to synthesize an unprecedented type of dehiscent mesoporous TiO2 microspheres with radial mesopore channels and oriented rutile crystallites. By varying the concentrated HCl amount, we have been able to produce TiO2 microspheres with well-controlled rutile/anatase phase ratio. By further manipulating the reaction conditions including solvent evaporation time and hydrothermal temperature, the oriented growth with tunable crevices can also be well manipulated. Such dehiscent mesoporous TiO2 microspheres have exhibited great permeability and excellent photocatalytic properties for H2 generation. We believe that the high structural complexity and predictability of this method offers great opportunities in enhancing the performance of TiO2-based materials. The development of porous materials and their applications has been in great demand recently. However, the progress in rational synthesis of porous semiconductors remains unproductive. Here, we have demonstrated a hydrothermal method to synthesize a novel type of mesoporous TiO2 microsphere with highly controllable structure. By regulating the synthetic conditions, the mesoporous TiO2 can be well controlled with oriented mesopores and lattices, tunable crystalline phase, and tailored open crevices. The resulting mesoporous TiO2 microspheres exhibit excellent penetration properties and photocatalytic activities, which is attributed to their unique mesostructures associated with accessible high surface area and particular architectures. Such a simple method, which is able to fabricate mesoporous TiO2 with controlled architectures and crystallites, is expected to be applied to produce numerous delicate nanostructures at moderate conditions for potential applications, such as catalysts, energy storage, and biosensors. We have demonstrated a facile hydrothermal approach to synthesize a novel type of mesoporous TiO2 material with highly controllable structure. By regulating the synthetic conditions, the mesoporous TiO2 can be well controlled with desired crystallites and architectures. The resulting mesoporous TiO2 exhibits excellent penetration properties and photocatalytic performance. These unique mesoporous TiO2 microspheres produced at moderate conditions could afford great opportunities in achieving high performance in various practical applications. The authors gratefully acknowledge funding support from the State Key Basic Research Program of China ( 2017YFA0207303 ), the National Science Foundation of China ( 21733003 ), Science and Technology Commission of Shanghai Municipality ( 17JC1400100 ), and Shanghai Leading Academic Discipline Project (B108). The authors extend their appreciation to the International Scientific Partnership Program ISPP at King Saud University for funding this research work through ISPP# 0018 . Scopus

Graphitic carbon nitride (g-C3N4) with efficient photocatalytic activity was synthesized through thermal polymerization of thiourea with the addition of water (CN-W) or ethanol (CN-E) at 550 °C for 2 h. The physicochemical properties of the g-C3N4 were investigated by X-ray diffraction, transmission electron microscopy, ultraviolet-visible spectroscopy, photoluminescence spectroscopy, diffuse-reflection spectroscopy, BET and BJH surface area characterization, and elemental analysis. The carbon content was found to have self-doped into the g-C3N4 matrix during the thermal polymerization of thiourea and ethanol. CN-W and CN-E showed considerably enhanced visible-light photocatalytic activity, with NO removal percentages of 37.2% and 48.3%, respectively. Compared with pure g-C3N4, both the short and long lifetimes of the charge carriers in CN-W and CN-E were found to be prolonged. The mechanism of improved visible-light photocatalytic activity was deduced. The present work may provide a facile route to optimize the microstructure of g-C3N4 photocatalysts for high-performance environmental and energy applications.

Semimetal bismuth with plasmonic properties has triggered increased interests. In this work, a facile strategy was developed to synthesize the Bi/(BiO)2CO3 (Bi-BOC) nanocomposites and Bi elemental photocatalysts. The Bi nanoparticles were produced via the insitu reduction of (BiO)2CO3 by NaBH4. The catalysts were utilized for the photocatalytic NO removal under visible light and UV illumination. Significantly, the photocatalytic capability of the Bi-BOC was highly enhanced with an unprecedented NO removal of 63.6%. The Bi metal demonstrated a direct plasmonic photocatalytic NO removal ratio of 53.6% under UV irradiation. The significantly enhanced photocatalytic capability of Bi-BOC can be ascribed to the synergistic effects of the SPR effect, enhanced visible-light-harvesting and the efficient electron–hole separation induced by Bi nanoparticles. The Bi nanoparticles can perform as a non-noble metal-based plasmonic cocatalyst for advancing photocatalytic ability. The mechanism of photocatalytic NO oxidation was proposed and compared under both visible light and UV illumination. Furthermore, the Bi-BOC photocatalysts showed good photochemical stability under repeated tests. This work could not only offer new insights into in-situ fine-tune reduction strategy for Bi-based photocatalysts, but also proves the potentials of utilizing low cost Bi cocatalysts as a substitute for noble metals to improve other photocatalysts.

The development of approaches to effectively separate the photo-induced charge carriers is a key strategy to promote the photocatalytic activity of semiconductor photocatalysts. This work represents the construction of novel two-dimensional (2D) BiOBr/C3N4 nanojunctions by the growth of BiOBr nanosheets on the surface of C3N4 nanosheets at room temperature. The samples were characterized by XRD, FT-IR, TEM, UV-vis DRS and PL. The photocatalytic activity of the samples was evaluated by the removal of NO in air under visible light irradiation. The results indicated that electronic coupling took place between the {001} plane of BiOBr and {002} plane of C3N4. The BiOBr/C3N4 nanojunctions exhibited enhanced visible light photocatalytic activity compared with pure BiOBr and C3N4. The enhanced photoactivity can be mainly ascribed to the efficient separation and transportation of photo-induced electrons and holes due to the well-coupled crystal planes and well-matched band structures. The present work could provide new insights into the design and construction of 2D nanojunctions with well-matched crystal planes and band structures for efficient visible light photocatalysis.