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In this work, shape manipulation in porous CeO2 nanofibers was successfully achieved by a simple electrospinning technology with high quality and high reproducibility. By simply tuning the electric field strength during electrospinning, the diameter of as-spun nanofibers composed of Ce(acac)3 and polyvinylpyrrolidone can be precisely controlled. As a result, the morphology of nanofibers can change from columnar to celery-like and belt-like structure. The formation mechanism of this intriguing diameter-dependent morphology can be assigned to the gradient evaporation of solvent across the nanofiber. After calcination at 500 °C, porous CeO2 nanofibers were obtained, showing unusually observed celery-like or belt-like morphologies. These intriguing CeO2 nanofibers exhibited good thermal stability in terms of phase structures and morphologies up to 700 °C. The fibrous CeO2 mats were active toward soot combustion with decreased activation energy, compared with commercial samples. Among three kinds of shapes, the fibrous CeO2 mats made of columnar-like nanofibers were endowed with the lowest activation energy of 120.1 kJ/mol, due to the most effective contact between soot and CeO2 surface, regardless a loose contact mode. [ABSTRACT FROM AUTHOR]

Catalyst sintering, a main cause of the loss of catalytic activity and/or selectivity at high reaction temperatures, is a major concern and grand challenge in the general area of heterogeneous catalysis. Although all heterogeneous catalysts are inevitably subjected to sintering during their operation, the immediate and drastic consequences can be mitigated by carefully engineering the catalytic particles and their interactions with the supports. In this tutorial review, we highlight recent progress in understanding the physical chemistry and materials science involved in sintering, including the discussion of advanced techniques, such as in situ microscopy and spectroscopy, for investigating the sintering process and its rate. We also discuss strategies for the design and rational fabrication of sinter-resistant catalysts. Finally, we showcase recent success in improving the thermal stability and thus sinter resistance of supported catalytic systems. [ABSTRACT FROM AUTHOR]

Abstract: New N‐doped reduced graphene oxide (N‐RGO) meshes are facile fabricated by selective etching of 3–5 nm nanopores, with controllable doping of N dopants at an ultrahigh N/C ratio up to 15.6 at%, from pristine graphene oxide sheets in one‐pot hydrothermal reaction. The N‐RGO meshes are illustrated to be an efficient metal‐free catalyst toward hydrogenation of 4‐nitrophenol, with new catalytic behaviors emerging in following three aspects: (i) tunable kinetics following pseudofirst order from commonly observed pseudozero order; (ii) strikingly improved activity with 26‐fold increased rate constant (1.0 s−1 g−1 L); (iii) no induction time required prior to reaction due to depressed back conversion, and dramatically decreased apparent activation energy (Ea) (17 kJ mol−1). The origin of these new catalytic properties can be assigned to the synergetic effects between graphitic N doping and structural defects arising from nanopores. Deeper understanding unveils that the concentration of graphitic N is inverse proportion to Ea, while the pyrrolic N has no impact on this reaction, and oxygenate groups hampers it. The porous nature allows the N‐RGO meshes to conduct catalyze reactions in continuous flow fashion. [ABSTRACT FROM AUTHOR]

This paper reports a facile fabrication of N-doped graphene quantum dots (N-GQDs) showing controllable chemical properties through a hydrothermal treatment. The N-GQDs have a uniform size of 3.06 ± 0.78 nm and prefer the equilibrium shapes of circle and ellipse due to the minimization of edge free energy. The N/ C atomic ratio in N-GQDs can be precisely tailored in a range from 8.3 at% to 15.8 at% by simply controlling the concentration of N source (ammonium hydroxide). One order of magnitude quantum yield of 34.5% is achieved by N-GQDs, compared with the N-free GQDs, as the substitutional N has an essential role in more effective radiative emission. Excessive N dopants in N-GQDs can lead to photoluminescence quenching, through nonradiative transition back to the ground state. The N-GQDs are further found to be suitable as photocurrent conversion materials due to benign energy matching with anatase nanofibers, the ultrafast electron injection at their interface, and efficient electron transfer. This work provides an efficient and inspiring approach to engineering both chemical components and physical properties of N-GQDs, and will therefore promote their basic research and applications in energy conversion. [ABSTRACT FROM AUTHOR]

Yunqian Dai and co‐workers report on page 597 how N dopants are tailored in the form of both substitutional and pyrrolic N in graphene quantum dots (N‐GQDs), showing controllable chemical properties. The substitutional N leads to significantly modified photoluminescence properties of the versatile N‐GQDs, which also exhibit highly efficient photocurrent conversion abilities when supported by anatase nanofibers. [ABSTRACT FROM AUTHOR]

Developing easy-tailorable and high-efficient electromagnetic interference (EMI) shielding textile from waste textile is highly desirable to meet the demand for wearable electronics and economic sustainability for modern society. However, simultaneously featuring with good electrical conductivity and wearability of the derived waste textiles remains a daunting challenge, especially in the absence of conducting additives. Herein, we report the fabrication of a tailorable textile with high flexibility and conductivity to address this challenge via a straightforward graphitization strategy based on a mild reduction procedure. Aided by finite element analysis (FEA) and computer simulation technology (CST) for performance screening in advance, the mechanically-favorable but EMI shielding-unfavorable pores intrinsically produced in interwoven textile call for a low square resistance of the whole textile. The textile with desirable features is fabricated by the Ni-species catalyzed graphitization of cotton cellulose with large-scale production potential. Moreover, the low square resistance of the textile remains stable after immersion in extremely corrosive chemicals or 10000-times bending tests. The textile with a small thickness of 1.4 mm achieves an EMI shielding effectiveness (SE) of 107 dB in 12–18 GHz, 3 fold exceeding the demand for commercial applications (>30 dB). Practical demonstrations show that personal information in a mobile phone or ID card can be prevented from being read by pockets tailored from textiles. This work shows great potential for massive production of high-efficiency EMI shielding textiles for livelihood or military towards the next-generation wearable electronic technology. A flexible textile of high-degree graphitization is achieved from waste cotton by employing Ni-species as the catalyst upon a mild reduction procedure. Featured with favorable conductivity and simultaneously intact interwoven framework, the textile maintains comfortable wearabilities and delivers an excellent electromagnetic shielding efficiency of 107 dB in 12–18 GHz. [Display omitted] [ABSTRACT FROM AUTHOR]

We report the fabrication of PdSm bimetallic nanocrystals with controlled shapes and explore their applications as the electrocatalysts for electroxidation of ethanol (EOR) in alkaline medium. The success of current synthesis relies on the co-reduction of Pd(acac) 2 and Sm(acac) 3 in the presence of N-oleyl-1,3-propanediamine (OPDA) and Mo(CO) 6 at an elevated temperature. For the first time, ultrathin nanostructures composed of Pd-rare earth metal bimetals could be prepared in high purity, in the form of ultrathin porous nanosheets and concave tetrahedra, together with the size/edge length limited to sub-3 nm size range. When serving as electrocatalysts for EOR, the carbon-supported PdSm nanocrystals exhibited in seven-fold increase in mass activity as compared to that of Pt/C, as well as improved reaction kinetics and long-term durability. DFT calculations verify that the PdSm NCs/C catalyst modulate the reaction pathway of ethanol oxidation with lower energy barriers as compared with Pd catalyst, accounting for the improved catalytic performance. The present study provides a feasible strategy to create rare earth metal-doped bimetallic nanocrystals with controlled morphology for rational design over fuel cell catalysts and could be extended to other noble metals or alloys. Ultrathin Sm-doped Pd nanocrystals with two exotic shapes, ultrathin porous nanosheet and concave tetrahedron, are successfully prepared via a one-pot synthesis, exhibiting noticeable enhancement in electrocatalytic activity for ethanol oxidation reaction in alkaline medium. [Display omitted] • Sm-doped Pd nanocrystals were facilely synthesized with ultrathin sizes. • The morphologies of porous nanosheet and concave tetrahedron were obtained. • PdSm NCs/C exhibited enhanced EOR mass activity, reaction kinetics and stability. • DFT calculations suggest the Sm-doping can lower the energy barriers for EOR. [ABSTRACT FROM AUTHOR]

Pt/TiO 2 nanofibers (Pt/T-NFs) composite catalysts are prepared through the combination of an electrospinning technique with a reductive impregnation method. Obtained samples are analyzed by various techniques, such as transmission electron microscopy and X-ray diffraction, which reveal that 21 wt.% Pt/T-NFs sample has a homogeneous distribution of smaller Pt nanoparticles of about 4.5 nm in size on the TiO 2 nanofibers surface without large aggregations. Electrochemical studies are carried out using cyclic voltammetry, chronoamperometry and CO stripping voltammetry, which indicate that 21 wt.% Pt/T-NFs catalyst has higher electrochemical surface area and much better activity for methanol electro-oxidation. All Pt/T-NFs catalysts have enhanced stability and CO tolerance for methanol electro-oxidation than commercial Pt/C. The results suggest that Pt/TiO 2 nanofibers catalysts exhibit the better activity for methanol oxidation and are favorable for improving the tolerance to poisoning species. [ABSTRACT FROM AUTHOR]

Different three-dimensional (3D) printing techniques are being increasingly used to produce medical apparatus due to their ability to print intended designs with high dimensional accuracy. Indeed, the major credit for the broad use of 3D printing techniques in medical fields stems from the ability of this method to prepare patient-matched devices due to the conventional manufacturing methods limitations such as economically inefficiency and multiple steps processing for complex geometries. This review manuscript aims to present brief insights of various 3D printing concepts and technologies used in the medical field. Biomaterials and bioprinting are pinpointed. Finally, the pharmaceutical potentials of 3D printing are discussed. Unlabelled Image • The contributions of Three-dimensional Printing in Healthcare and Medicine. • A comprehensive review of technologies types used in 3D printing. • Discussing the foremost applications and approaches to Bio-materials-based Additive Manufacturing technology. • Addressing the advantages of three-dimensional printing in relation to medical implants. [ABSTRACT FROM AUTHOR]

Photocatalyst-assisted degradation of organic pollutants, which exhibits a novel strategy for solar-energy utilization, possesses enormous potential in various applications. Extending the light-absorption range in the spectrum of sunlight and improving light-conversion efficiency are always primary issues to enhance the catalytic performance of these photocatalysts. Herein, a new structure of gold-nanorod-decorated TiO2 rambutan-like microspheres is designed, which exhibits superior photocatalytic ability toward Rhodamine B in the range of visible light due to the 3D distribution of the TiO2 branches on the surface of the microspheres, which prompts the multireflection of photons. The absorption rate of photons is thereby tremendously enhanced. This is beneficial for the generation of hot electrons originating from the localized surface plasmonic resonance of Au nanorods, which can be used to both initiate the reaction and produce the photothermal effect. Hot electrons generated by a single Au nanorod in microspheres to initiate the degradation reaction can be as high as 2.5 times of those in the nanowires' counterpart. Moreover, the heating power of a single Au nanorod in microspheres reaches up to 4.4 times higher than that in nanowires, which further accelerates the degradation rate. The reaction pathway of visible-light-assisted RhB degradation catalyzed by Au/TiO2 microspheres goes through an initial N-deethylation process instead of the complete cycloreversion catalyzed by pure TiO2 microspheres under UV irradiation. This strategy of structure design for improved photon absorption, which achieves high degradation rate and photothermal effect, is promising for the development of novel photocatalysts. [ABSTRACT FROM AUTHOR]

Under the smart screening design, brittle oxide nanofibers are assembled into elastic aerogel by graphene crosslinkers, demonstrated with multifunction in efficient solar evaporation, space-efficient transporting, intriguing microplastic-removing from water, and reusing as thermal-insulating or smart sensing. [Display omitted] • Under smart simulation, ambient-derived elastic aerogel is assembled from fragments. • The evaporator harvests clean water from microplastic-pollutant powered by sunlight. • Multifunctional evaporator is reused as wearable cold-defending and smart sensing. Lightweight aerogel with functionally-elastic three-dimensional (3D) networks holds great promise, but their function realization is seriously plagued by weak assembling of building blocks with poor mechanical-stabilities. Herein, facile crosslinking brittle oxide nanofibers into elastic 3D fibrous aerogels was demonstrated based on smart screening of components and structures from nanoscale to macroscale in finite element analysis. By employing reduced graphene oxide (RGO) sheets as glues and air bubbles as templates, a simple approach to scalable synthesis of fibrous aerogels was developed. Despite involving rigid oxide element, the fibrous aerogel has good elasticity (under 1000-cycled compressions, withstanding − 196 to 700 °C), ultralow density (7.02 mg·cm−3), ultra-rapid photothermal conversion and water absorption. With these merits, it can efficiently evaporate water from microplastic-polluted seawater powered by solar, enable the vapor to be naturally condensated and harvested in well-designed electricity-free system. High solar-to-vapor efficiency over 100% (1 sun) and microplastic removal efficiency (∼100%) are achieved. Superior to reported evaporators, such elastic aerogel can be reused in wearable cold-defending and pressure sensing even after solar-evaporation. This work provides a universal strategy for smart-simulation designing and simple assembling multifunctional architectures even from brittle building-blocks, opening doors to new opportunities in many advanced applications. [ABSTRACT FROM AUTHOR]

We report the synthesis of a novel compound, 9,9-bis(3′-aminopropyl)-2,7-diphenylfluorene (BAPDPF), and a new approach to graft the BAPDPF onto a CdS quantum dot (QD) surface via an acylation reaction. FT-IR and TGA characterizations indicate the formation of robust bonding between BAPDPF and QDs; the structures of the bare QDs and BAPDPF–CdS QD hybrid nanocomposites estimated by transmission electron microscopy (TEM) showed that they have the same size of about 3.5 nm. The extent of the spectral overlap between the emission of BAPDPF and absorption of QDs, and the change of fluorescence emission for the organic and inorganic components of the hybrid, demonstrate that the energy transfer process occurs from BAPDPF to the CdS QDs. The energy transfer of about 44% efficiency is corroborated by time-resolved fluorescence measurements, and then the solid-state photoluminescence quantum yield (PLQY) of the nanocomposite is measured using an integrating sphere and a conventional fluorimeter. Because of the fact that the PLQY of the nanocomposite is 9.1 times larger than that of the pristine QDs, due to the energy transfer between the donor and the acceptor and passivation effects on the surface of the acceptor, the presented BAPDPF–CdS QD hybrid nanocomposites are potentially interesting in nanoparticle-based light-emitting devices. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two host materials for solution-processed green PhOLEDs were synthesized. [•] The hosts exhibit high triplet energy, excellent thermal and morphological stability. [•] The solution-processed single-layer green device shows the LE of 10.1cd/A. [ABSTRACT FROM AUTHOR]

Abstract: A dendritic host material 4,4-bis[3,6-bis(3,6-di-tert-butylcarbazol-9-yl)-carbazol-9-yl]-biphenyl for solution-processed blue phosphorescent organic light-emitting devices was designed and synthesized. Owing to the decrease of the π conjugation length of biphenyl moiety in molecule structure, this carbazole derived derivative shows high triplet energy. Furthermore, the thermal, photophysical and electrochemical properties of 4,4-bis[3,6-bis(3,6-di-tert-butylcarbazol-9-yl)-carbazol-9-yl]-biphenyl were investigated. The high triplet energy of 4,4-bis[3,6-bis(3,6-di-tert-butylcarbazol-9-yl)-carbazol-9-yl]-biphenyl ensures efficient energy transfer from the host to the triplet emitter iridium(III) bis(4,6-difluorophenylpyridinato)picolinate. The single layer device using the carbazole derivatives as the host for iridium(III) bis(4,6-difluorophenylpyridinato)picolinate showed the maximum luminance efficiencies of 5.8 cd A−1, and a maximum external quantum efficiency 2.8%. The efficiency of the carbazole derivative based device was almost 3 times higher than the corresponding 1,3-bis(9-carbazolyl)benzene based device. [Copyright &y& Elsevier]

Based on the solid-state electrochemiluminescence (ECL) of an electrogenerated polypyrrole tagged with tris(2,2′-bipyridyl)ruthenium(II) complex ( denoted as polypyr-Ru), a new ethanol biosensor was fabricated by casting the composite of alcohol dehydrogenase (ADH) and laponite colloids onto the polypyr-Ru /Pt electrode. The two layer structure keeps the good robustness of the biosensor due to the electrostatic interaction between the negatively charged biocomposite coating and the positively charged polypyr-Ru. The morphology of the laponite-ADH composite coating is characterized by scanning electron microscopy. The electrochemical and ECL properties of the modified electrodes are investigated by cyclic voltammetry. The parameters concerning the ECL biosensor such as the amount of enzyme usage, the appropriate pH are optimized. The resulted ECL biosensor shows a good performance to detect ethanol. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports the synthesis and physical properties of a series of bipolar host materials, using of a hole-transporting triphenylamine (TPA) monomer as a core incorporated with different numbers of diphenylphosphine oxide (PO) as electron-transporting moieties, 4-(diphenylphosphoryl)-N,N-diphenylaniline (DDPA), 4-(diphenylphosphoryl)-N-(4-(diphenylphosphoryl)phenyl)-N-phenylaniline (DDPP), and tris(4-(diphenylphosphoryl)phenyl)amine (TDPA), for solution-processed deep-blue phosphorescent organic light-emitting devices (PhOLEDs). With the increasing numbers of PO units, the glass-transition temperature of those compounds rise gradually. Moreover, the newly synthesized compounds all possess high triplet energies, which can prevent back energy transfer between the host and dopant molecules, and are expected to serve as appropriate hosts for iridium(III) tris(3,5-difluoro-4-cyanophenyl)pyridinato-N,C′ (FCNIrpic). The solution-processed devices using DDPP and TDPA as the hosts for the phosphorescence emitter FCNIrpic showed the maximum luminance efficiencies of 9.7 and 6.6cdA−1, respectively. The efficiency of TDPA based device shows nearly three times higher than the value of commonly used host material 1,3-bis(9-carbazolyl)benzene (mCP) with the same structure, which is outstanding with respect to other works related to the solution-processed deep-blue PhOLEDs based on small-molecule hosts. [Copyright &y& Elsevier]

Abstract: This paper reports the synthesis and physical properties of two novel carbazole-based dendritic host materials Cz-CCP and Cz-mCP for solution-processed blue phosphorescent organic light-emitting devices (PhOLEDs). These dendritic hosts exhibit high triplet energy (≥2.85 eV), excellent film-forming ability (with low root-mean-square (rms) values less than 0.2 nm), high glass-transition temperatures in the range of 242–248 °C, and the appropriate HOMO energy levels (−5.33–−5.35 eV) facilitating the transfer of holes from Poly(3,4-ethylenedioxythiophene):Poly(styrene-4-sulfonate) (PEDOT:PSS) to the emitting layer. The single-layer device using Cz-CCP and Cz-mCP as the host for the phosphorescence emitter iridium(III) bis(4,6-difluorophenylpyridinato)-picolinate (FIrpic) showed the maximum luminance efficiencies of 9.6 and 10.8 cd A−1, respectively. By introducing a thin 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBI) electron-transporting and exciton-confining layer, the maximum efficiency of the solution-processed double-layer device based on Cz-CCP and Cz-mCP can be further improved to 20.5 and 22.7 cd A−1, and maximum external quantum efficiencies as high as 10.2% and 11.5%, respectively. These results demonstrated that the newly synthesized, carbazole-based dendritic host materials are advantageous for fabrication of highly efficient blue PhOLEDs. [Copyright &y& Elsevier]

The massive plastic production worldwide leads to a global concern for the pollution made by the plastic wastes and the environmental issues associated with them. One of the best solutions is replacing the fossil-based plastics with bioplastics. Bioplastics such as polylactic acid (PLA) are biodegradable materials with less greenhouse gas (GHG) emissions. PLA is a biopolymer produced from natural resources with good mechanical and chemical properties, therefore, it is used widely in packaging, agriculture, and biomedical industries. PLA products mostly end up in landfills or composting. In this review paper, the existing life cycle assessments (LCA) for PLA were comprehensively reviewed and classified. According to the LCAs, the energy and materials used in the whole life cycle of PLA were reported. Finally, the GHG emissions of PLA in each stage of its life cycle, including feedstock acquisition and conversion, manufacturing of PLA products, the PLA applications, and the end of life (EoL) options, were described. The most energy-intensive stage in the life cycle of PLA is its conversion. By optimizing the conversion process of PLA, it is possible to make it a low-carbon material with less dependence on energy sources. [ABSTRACT FROM AUTHOR]

• The surface uniformity of substrate was optimized toward sinter-resistant catalyst. • TiO 2 nanofibers were decorated with well-defined rutile nanorods as substrate. • 3 nm-Pt NPs were stabilized under sinter-promoting situations over 600 °C. • Pt NPs on the nanorods-decorated-TiO 2 nanofibers were active for soot oxidation. One of the most urgent concerns for supported catalysts is to enhance their thermal stability against sintering upon high temperatures (above 300 °C). In this work, we decorated the rough surface of TiO 2 nanofibers with a sheath of rutile nanorods to improve their surface uniformity and explored them as new reliable substrates to stabilize Pt nanoparticles without capping shell. During preparation, the surface-initiated grain growth facilitates the decorated TiO 2 crystals to transform into rutile nanorods, exposing rutile {1 1 1} and {1 1 0} facets. With the presence of TiO 2 nanofibers, these rutile nanorods were finely confined against coalescence and reconstruction upon 700 °C, offering reliable supports for stabilizing metal nanoparticles. Therefore, the diminished driving force for sintering enables the whole catalyst system to withstand temperatures up to 500 °C at an oxidative atmosphere. After calcination at 500 °C, the Pt on rutile nanorods-decorated-TiO 2 nanofibers exhibited nearly 3-times higher reaction rate constant (27.8 s−1·g−1·L−1) toward hydrogenation of 4-nitrophenol over those on unmodified TiO 2. Moreover, such a thermally stable catalyst was active for the oxidation of soot particulates, decreasing the conversion temperature and maintaining a small Pt size of 6.99 nm after the sinter-promoting exothermic oxidation. [ABSTRACT FROM AUTHOR]