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Perovskite nanocrystals (PNCs) bear a huge potential for widespread applications, such as color conversion, X-ray scintillators, and active laser media. However, the poor intrinsic stability and high susceptibility to environmental stimuli including moisture and oxygen have become bottlenecks of PNC materials for commercialization. Appropriate barrier material design can efficiently improve the stability of the PNCs. Particularly, the strategy for packaging PNCs in organosilicon matrixes can integrate the advantages of inorganic-oxide-based and polymer-based encapsulation routes. However, the inert long-carbon-chain ligands (e.g., oleic acid, oleylamine) used in the current ligand systems for silicon-based encapsulation are detrimental to the cross-linking of the organosilicon matrix, resulting in performance deficiencies in the nanocrystal films, such as low transparency and large surface roughness. Herein, we propose a dual-organosilicon ligand system consisting of (3-aminopropyl)triethoxysilane (APTES) and (3-aminopropyl)triethoxysilane with pentanedioic anhydride (APTES-PA), to replace the inert long-carbon-chain ligands for improving the performance of organosilicon-coated PNC films. As a result, strongly fluorescent PNC films prepared by a facile solution-casting method demonstrate high transparency and reduced surface roughness while maintaining high stability in various harsh environments. The optimized PNC films were eventually applied in an X-ray imaging system as scintillators, showing a high spatial resolution above 20 lp/mm. By designing this promising dual organosilicon ligand system for PNC films, our work highlights the crucial influence of the molecular structure of the capping ligands on the optical performance of the PNC film.

In order to achieve high throughput and low-power consumption of the transmitter and improve the error performance of the receiver, a novel reconfigurable intelligent surface (RIS)-aided code index modulation (RIS-CIM) is proposed in wireless communications. RIS-CIM utilizes the index of a spreading code to convey additional information, which further improves the spectral efficiency (SE) and error performance of the receiver by adding and adjusting the reflected phase shift of low-cost reflective elements at the RIS-aided relay. To reduce the computational complexity incurred by the maximum likelihood (ML) detection, we propose two low-complexity detections, namely the match correlation (MC) detection and the optimal low complexity (OLC) detection. MC and OLC approaches separate the dispreading from the demodulation in the detection, which achieves a significant reduction of the computational complexity over ML detection demonstrated by the analysis of the computational complexity measurements. We present a thorough analysis for the upper bound on the average bit error probability (ABEP) of the ML detection and the bit error probability (BEP) of the OLC detection of RIS-CIM, which is verified by numerical simulations. Numerical simulations also demonstrate that the proposed RIS-CIM performs better in terms of the error performance of ML detection than several existing CIM and RIS-related schemes at a given SE setting. In addition, the proposed ML and OLC detections achieve an error performance close to the ML detection under various measures of signal-to-noise ratio (SNR) and the increasing SE in the simulations. Moreover, RIS-CIM can utilize a large number of reflective elements at the RIS-aided relay to offset the performance degradation caused by the improvement of SE.

Metal–support-interactions (MSIs) are critical in catalyst design and optimization toward enhancing the solar-driven photocatalytic hydrogen-evolution-reaction (HER). Transition metal phosphates (TMPs) have been predicted as promising catalysts for the photocatalytic HER owing to their high chemical diversity and superior optical properties. However, it has been found that TMPs suffer from strong hydrogen adsorption and weak desorption, leading to unbalanced hydrogen absorption/desorption behavior and a sluggish photocatalytic HER process. Herein, an MSI was delicately designed by embedding Pt-nanoparticles into porous iron phosphide nanorods (MSI Pt–Fe2P) viaa facile metal–organic-framework (MOF)-derived approach assisted by phosphating treatment. Experimental characterization and theoretical calculations disclose that the formation of MSI resulted in regulating the electronic structure and balancing the hydrogen absorption/desorption behavior of Fe2P. Benefiting from the alteration of the electronic structure, the resultant Pt–Fe2P featuring an MSI enables a remarkable photocatalytic HER rate of 6 mmol g−1h−1with a high apparent quantum efficiency of 20% at 500 nm wavelength. This finding may pave the way for developing more efficient TMP-based catalysts for various solar energy applications.

To boost electrocatalytic performance, efficient electrocatalysts generally require an appropriate adsorption/desorption intensity for intermediates, and a favorable transportation capability of mass and electrons. For preparing electrocatalysts with excellent performance, the crystallinity, morphology and composition of the materials should be considered. Aiming to split water, here we proposed a MOF-derived route to prepare a series of composition-tunable Fe–Ni bimetallic phosphides as efficient electrocatalysts. By controlling the phosphating temperature, electrocatalysts with tubular or porous nanostructures can be selectively obtained, and crystallinity, morphology and composition of the electrocatalysts can be well tuned. The effects of synergistic modulation of the above parameters for electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were deeply explored, and overall water splitting was achieved with an overpotential of about 1.63 V@10 mA cm−2. This work not only provides a facile method to obtain composition- and morphology-tunable phosphide electrocatalysts for water splitting, but also sheds new light on designing efficient electrocatalysts from a systematic viewpoint.

Federated edge learning (FEEL) technology for vehicular networks is considered as a promising technology to reduce the computation workload while keeping the privacy of users. In the FEEL system, vehicles upload data to the edge servers, which train the vehicles' data to update local models and then return the result to vehicles to avoid sharing the original data. However, the cache queue in the edge is limited and the channel between edge server and each vehicle is time-varying. Thus, it is challenging to select a suitable number of vehicles to ensure that the uploaded data can keep a stable cache queue in edge server while maximizing the learning accuracy. Moreover, selecting vehicles with different resource statuses to update data will affect the total amount of data involved in training, which further affects the model accuracy. In this paper, we propose a vehicle selection scheme, which maximizes the learning accuracy while ensuring the stability of the cache queue, where the statuses of all the vehicles in the coverage of edge server are taken into account. The performance of this scheme is evaluated through simulation experiments, which indicates that our proposed scheme can perform better than the known benchmark scheme.

Differential spatial modulation (DSM) is a multi-antenna technique that does not require channel state information (CSI). However, DSM has a deficiency of low spectral efficiency (SE). In this paper, a differential space-time media-based modulation (DSTMBM) system is proposed. The DSTMBM system equips radio frequency (RF) mirrors to transmit additional bits, which leads to an improvement of SE. Simulation results show that the bit error rate (BER) performance of DSTMBM is about 4 dB better than that of DSM under the same parameters. For low-complexity implementation, a genetic algorithm aided compressed sensing (GA-CS) detector is tailored to the DSTMBM system. Compared with the state-of-the-art low-complexity detector with the best performance in differential systems, the GA-CS detector achieves a complexity reduction of 3 orders of magnitude when the transmit matrix dimensions are $8\times 8$, at the cost of only around 1 dB in terms of BER performance. Furthermore, the complexity of GA-CS detector does not grow exponentially with the matrix dimension.

With the merits of quantum dots (QDs) (e.g., high molar extinction coefficient, strong visible light absorption, large specific surface area, and abundant functional surface active sites) and aerogels (e.g., self-supported architectures, porous network), semiconductor QD aerogels show great prospect in photocatalytic applications. However, typical gelation methods rely on oxidative treatments of QDs. Moreover, the remaining organic ligands (e.g., mercaptoacids) are still present on the surface of gels. Both these factors inhibit the activity of such photocatalysts, hampering their widespread use. Herein, we present a facile 3D assembly of II–VI semiconductor QDs capped with inorganic (NH4)2S ligands into aerogels using H2O as a dispersion solvent. Without any sacrificial agents, the resulting CdSe QD aerogels achieve a high CO generation rate of 15 μmol g–1h–1, which is 12-fold higher than that of pristine-aggregated QD powders. Our work not only provides a facile strategy to fabricate QD aerogels but also offers a platform for designing advanced aerogel-based photocatalysts.

Metal halide perovskites (MHPs) are a special class of photocatalysts that exhibit excellent performance in photocatalysis. This review gives a comprehensive overview of their recent advances.

Photocatalytic CO2reduction is an appealing approach to convert solar energy into high value-added chemicals. All-inorganic CsPbBr3quantum dots (QDs) have emerged as a promising photocatalyst for reducing CO2. However, pristine CsPbBr3has a low catalytic performance, mainly due to severe charge recombination. Herein, a 0D/2D heterojunction of CsPbBr3QDs/Bi2WO6nanosheet (CPB/BWO) photocatalysts is fabricated for photocatalytic CO2reduction. The CPB/BWO photocatalyst achieves excellent photocatalytic performance: the total yield of CH4/CO is 503 μmol g–1, nearly 9.5 times higher than the pristine CsPbBr3. The CPB/BWO heterojunction also exhibits much-improved stability during photocatalytic reactions. On the basis of various characterization techniques, our investigations verified a direct Z-scheme charge migration mechanism between CsPbBr3QDs and Bi2WO6nanosheets. The improved photocatalytic performance is originated from the high spatial separation of photoexcited charge carriers in CPB/BWO, which can also preserve strong individual redox abilities of two components. This work reports an efficient direct Z-scheme heterojunction photocatalytic system based on metal halide perovskites. The novel strategy we proposed may bring up new opportunities for the development of metal halide perovskite photocatalysts with greatly enhanced activities.

Converting CO2into chemical fuels with a photocatalyst and sunlight is an appealing approach to address climate deterioration and energy crisis. Metal complexes are superb candidates for CO2reduction due to their tunable catalytic sites with high activity. The coupling of metal complexes with organic photosensitizers is regarded as a common strategy for establishing photocatalytic systems for visible-light-driven CO2reduction. While most of the organic photosensitizers generally contain precious metals and are available through onerous synthetic routes, their large-scale application in the photocatalysis is limited. Halide perovskite nanocrystals (NCs) have been considered as one of the most promising light-harvesting materials to replace the organic photosensitizers due to their tunable light absorption range, low cost, abundant surface sites, and high molar extinction coefficient. Herein, we demonstrate a facile strategy to immobilize [Ni(terpy)2]2+(Ni(tpy)) on inorganic ligand-capped CsPbBr3NCs and to apply this hybrid as a catalyst for visible-light-driven CO2reduction. In this hybrid photocatalytic system, the Ni(tpy) can provide specific catalytic sites and serve as electron sinks to suppress electron–hole recombination in the CsPbBr3NCs. The CsPbBr3-Ni(tpy) catalytic system achieves a high yield (1724 μmol/g) in the reduction of CO2to CO/CH4, which is approximately 26-fold higher than that achieved with the pristine CsPbBr3NCs. This work has developed a method for enhancing the performance of photocatalytic CO2reduction by immobilizing metal complexes on perovskite NCs. The methodology we present here provides a new platform for utilizing halide perovskite NCs for photocatalytic applications.

In direct-current biased optical orthogonal frequency division multiplexing (DCO-OFDM), a constant DC bias is introduced to render the bipolar signal non-negative. However, due to the inherent disadvantage of high peak-to-average power ratio (PAPR), the DC bias should be set to a relatively high level to suppress the clipping distortion, resulting in power inefficiency. Therefore, we conceive a novel adaptively biased optical OFDM (ABO-OFDM) for optical wireless communication (OWC), where the bias is dynamically optimized according to the signal magnitude to enhance the power efficiency. Meanwhile, the interference induced by the adaptive bias is placed on the reserved subcarriers, which avoids contaminating the legitimately transmitted information data. The implementation complexity of the ABO-OFDM transceiver is almost the same as asymmetrically clipped optical OFDM (ACO-OFDM), which is notably lower than the superimposed OFDM schemes. Numerical results have demonstrated that the proposed ABO-OFDM outperforms the conventional DCO-OFDM and ACO-OFDM in terms of power efficiency.

In recent years, halide perovskites have attracted considerable attention for photocatalytic CO2reduction. However, the presence of surface defects and the lack of specific catalytic sites for CO2reduction lead to low photocatalytic performance. In this study, we demonstrate a facile method that post-treats CsPbBr3with ZnBr2for photocatalytic CO2reduction. Our experimental and characterization results show that ZnBr2has a dual role: the Br–ions in ZnBr2passivate Br vacancies (VBr) on the CsPbBr3surface, while Zn2+cations act as catalytic sites for CO2reduction. The ZnBr2–CsPbBr3achieves a photocatalytic CO evolution rate of 57 μmol g–1h–1, which is nearly three times higher than that of the pristine CsPbBr3. The enhanced performance over ZnBr2–CsPbBr3is mainly due to the decreased VBrand lower reaction energy barrier for CO2reduction. This work presents an effective method to simultaneously passivate surface defects and introduce catalytic sites, providing useful guidance for the regulation of perovskite photoelectric properties and the design of efficient photocatalysts.

Converting CO2into high-value-added chemicals has been recognized as a promising way to tackle the fossil fuel crisis. Quantum dots (QDs) have been extensively studied for photocatalytic CO2reduction due to their excellent optoelectronic properties. However, most of the photogenerated charge carriers recombine before they participate in the photocatalytic reaction. It is crucial to regulate the charge carriers to minimize undesired charge recombination, thus, promoting surface photocatalysis. Herein, we report a copper-doped CdS (Cu:CdS) QD photocatalyst for CO2reduction. Density functional theory simulations and experimental results demonstrate that Cu dopants create intermediate energy levels in CdS QDs that can extend the lifetime of exciton charge carriers. Furthermore, the long-lived charge carriers can be harnessed for the photocatalytic reaction on Cu:CdS QDs. The resultant Cu:CdS QDs exhibited a significantly enhanced photocatalytic activity toward CO2reduction compared to the pristine CdS QDs. This work highlights the importance of charge regulation in photocatalysts and opens new pathways for the exploration of efficient QD photocatalysts.

Two-dimensional semiconductors are extensively discussed materials for photocatalytic reactions; however, their active sites originate from in-plane surface pits (SPs), and understanding their underlying mechanism remains challenging. Herein, unique BiOCl nanoplates with SP (BiOCl-SP) are developed via a non-rapid synthetic route for CO2photoreduction. Unlike conventional photocatalysts, owing to SP, BiOCl-SP features multiple active sites, including spatially separated and coordinatively unsaturated sites disclosed by kinks and atomic steps, super-exposed sublayer lattices with order/disorder symmetry, and Bi-oxygen defects associates. The synergy of active sites in BiOCl-SP enables accelerated charge separation/transfer to the surface with hampered recombination. Consequently, BiOCl-SP exhibits a remarkable CO production rate of 89.72 μmol·g−1·h−1with excellent stability/reproducibility in a period of 30 h CO2photoreduction, in pure water without introducing any sacrificial agents or co-catalysts. Notably, the activity of BiOCl-SP outperforms a series of pit-free state-of-the-art photocatalysts, and promisingly, our synthetic approach is scalable and applicable to BiOBr and BiOI photocatalysts. This work highlights cost-effective pit engineering in bismuth-based materials to achieve efficient photocatalysis and motivates exploring other pits-confined materials for practical applications.

Combination of upconversion nanocrystals (UCNs) with CeO2is a decent choice to construct NIR-activated photocatalysts for utilizing the NIR light in the solar spectrum. Herein we present a facile approach to deposit a CeO2layer with controllable thickness on the plate-shaped NaYF4:Yb,Tm UCNs. The developed core–shell nanocomposites display obvious photocatalytic activity under the NIR light and exhibit enhanced activity under the full solar spectrum. For enhancing the separation of photogenerated electrons and holes on the CeO2surface, we sequentially coat a ZnO shell on the nanocomposites so as to form a heterojunction structure for achieving a better activity. The developed hybrid photocatalysts have been characterized with TEM, SEM, PL, etc., and the working mechanism of such UCN-semiconductor heterojunction photocatalysts has been proposed.

Development of MOF-based photocatalysts is intriguing research due to their structural flexibility and tremendous catalytic sites, whereas most MOFs only can take use of UV/visible light and lack of response to NIR light. Herein, we present a facile approach to integrate upconversion nanoparticles (UCNPs) with MOF to build a NIR-responsive composite photocatalyst. The MOF shell with controllable thickness can be grown on the UCNPs, thus exhibiting tunable photocatalytic activities under NIR irradiation. Furthermore, we extend visible absorption of the MOF shell by adding −NH2groups so that the composite photocatalysts have a better utilization of UC emissions and sunlight to improve their activities. The developed composite photocatalysts have been characterized by XRD, TEM, PL, etc., and their photocatalytic performances were systematically explored. The formation and working mechanism of the composite photocatalysts were also elucidated.

Wireless network virtualization and ICN are two promising technologies for next generation wireless networks. Although some excellent works have focused on these two technologies, D2D communications have not been investigated in information-centric virtualized cellular networks. Meanwhile, content caching in mobile devices has attracted much attention due to the saved backhaul consumption or reduced transmission latency in D2D-assisted cellular networks. However, when it comes to the multi-operator scenario, direct content sharing between different operators via D2D communications is typically infeasible. In this article, we propose a novel information-centric virtualized cellular network framework with D2D communications, enabling not only content caching in the air, but also inter-operator content sharing between mobile devices. We describe the key components in the proposed framework, and present the interactions among them. We incorporate and formulate the content caching strategies in resource allocation optimization, to maximize the total utility of mobile virtual network operators (MVNOs) by caching popular content in mobile devices. Simulation results demonstrate the effectiveness of the proposed framework and scheme with different system parameters.

The construction of a p-n heterojunction is an efficient strategy to resolve the limited light absorption and serious charge-carrier recombination in semiconductors and enhance the photocatalytic activity. However, the promotion effect is greatly limited by poor interfacial charge transfer efficiency as well as reduced redox ability of charge carriers. In this work, we demonstrate that the embedding of metal Pd into the interface between n-type C3N4and p-type Cu2O can further enhance the interfacial charge transfer and increase the redox ability of charge carriers through the design of the C3N4-Pd-Cu2O stack nanostructure. The embedded Pd nanocubes in the stack structure not only trap the charge carriers from the semiconductors in promoting the electron–hole separation but also act as a Z-scheme “bridge” in keeping the strong reduction/oxidation ability of the electrons/holes for surface reactions. Furthermore, Pd nanocubes also increase the bonding strength between the two semiconductors. Enabled by this unique design, the hydrogen evolution achieved is dramatically higher than that of its counterpart C3N4-Cu2O structure without Pd embedding. The apparent quantum efficiency (AQE) is 0.9% at 420 nm for the designed C3N4-Pd-Cu2O. This work highlights the rational interfacial design of heterojunctions for enhanced photocatalytic performance.

Abstract

Lanthanide-doped upconversion nanocrystals which can convert near-infrared lights to visible lights have attracted growing interest because of their great potentials in biomedical engineering. However, it remains a grand challenge to maneuver the intensity ratio between different emission lines and enable tunable upconversion functions. Herein, we present a facile method to integrate NaYF4:Yb,Er upconversion nanocrystals with gold nanocrystals for constructing NaYF4:Yb,Er@SiO2@Au hybrid nanostructures, in which a silica layer on NaYF4:Yb,Er nanocrystals serves as an interface for gold decoration. The green-to-red emissions of the upconversion nanocrystals can be conveniently tuned by altering the amount of surrounding gold nanocrystals. We further demonstrate the capability of utilizing both green and red emission lines for spontaneous signaling in an emitter−quencher-based bioassay by implementing this novel hybrid nanostructure. It is anticipated that the controllability in upconversion fluorescence in this hybrid nanostructure may provide a platform for widely exploring applications in biological imaging, detection, and sensing.

Utilizing sunlight to convert CO2into chemical fuels could simultaneously address the greenhouse effect and fossil fuel crisis. ZnSe nanocrystals are promising candidates for photocatalysis because of their low toxicity and excellent photoelectric properties. However, pristine ZnSe generally has low catalytic activities due to serious charge recombination and the lack of efficient catalytic sites for CO2reduction. Herein, a ZnSe nanorods–CsSnCl3perovskite (ZnSe–CsSnCl3) type II heterojunction composite is designed and prepared for photocatalytic CO2reduction. The ZnSe–CsSnCl3type II heterojunction composite exhibits enhanced photocatalytic activity for CO2reduction with respect to pristine ZnSe nanorods. The experimental characterizations and theoretical calculations reveal that the efficient charge separation and lowered free energy of CO2reduction facilitate the CO2conversion on the ZnSe–CsSnCl3heterojunction composite. This work presents a type II heterojunction composite photocatalyst based on ecofriendly metal chalcogenides and metal halide perovskites. Our study has also promoted the understanding of the CO2reduction mechanisms on perovskite nanocrystals, which could be valuable for the development of metal halide perovskite photocatalysts.

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Abstract: Two-dimensional (2D) hierarchical tin dioxide (SnO2) flower-like architectures consisting of sheet-like nanoparticles have been successfully prepared by a simply mild hydrothermal method based on the reaction between tin foil, NaOH and KBrO3. The photoluminescence (PL) spectrum exhibit that the flower-like architectures of SnO2 have strong PL emission, which suggest its possible applications in nanoscaled optoelectronic devices. The formation process of SnO2 architectures is investigated and the corresponding mechanism is also proposed.

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A solution surface‐erosion route was successfully employed to produce one‐dimensional (1D) ZnO nanostructures. ZnO nanorod arrays and three‐dimensional urchin‐like assemblies could be selectively obtained with different manipulations. In this process, zinc foil was introduced to an organic solution system and acted both as a reactant and substrate to support the 1D nanostructures obtained. This method, without any template, apparatus, surfactants, or additional heterogenous substrates, has greatly simplified the preparation of oriented 1D ZnO nanostructures. In particular, this simple route could be carried out at room temperature over a period as short as several minutes, thus it could be conveniently transferred to industrial applications. The possible formation mechanism, erosion process, and influence factors were also investigated.

A general synthetic route has been developed for the growth of metal phosphide, oxide, sulfide, and tungstate nanowires in aqueous solution. In detail, cetyltrimethylammonium cations (CTA⁺) can be combined with anionic inorganic species along a co-condensation mechanism to form lamellar inorganic–surfactant intercalated mesostructures, which serve as both microreactors and reactants for the growth of nanowires. For example, GaP, InP, γ-MnO2, ZnO, SnS2, ZnS, CdWO4, and ZnWO4 nanowires have been grown by this route. To the best of our knowledge, this is the first time that the synthesis of GaP and InP nanowires in aqueous solution has been achieved. This strategy is expected to extend to grow nanowires of other materials in solution or by vapor transport routes, since the nanowire growth of any inorganic materials can be realized by selecting an appropriate reaction and its corresponding lamellar inorganic–surfactant precursors.

A general synthetic route has been developed for the growth of metal phosphide, oxide, sulfide, and tungstate nanowires in aqueous solution. In detail, cetyltrimethylammonium cations (CTA+) can be combined with anionic inorganic species along a co‐condensation mechanism to form lamellar inorganic–surfactant intercalated mesostructures, which serve as both microreactors and reactants for the growth of nanowires. For example, GaP, InP, γ‐MnO2, ZnO, SnS2, ZnS, CdWO4, and ZnWO4nanowires have been grown by this route. To the best of our knowledge, this is the first time that the synthesis of GaP and InP nanowires in aqueous solution has been achieved. This strategy is expected to extend to grow nanowires of other materials in solution or by vapor transport routes, since the nanowire growth of any inorganic materials can be realized by selecting an appropriate reaction and its corresponding lamellar inorganic–surfactant precursors.

Group IIIA nitrides have been synthesized in aqueous solution under mild conditions for the first time. The reaction was carried out in an aqueous solution with NH4Cl as nitrogen source at 250 °C. X-Ray diffraction, transmission electronic microscope, high-resolution transmission electron microscopy, electronic diffraction patterns, X-ray photoelectron spectra, energy-dispersive X-ray analysis, infrared absorption spectra and ultraviolet and visible light UV-vis spectra were used to characterize the products. It was found that the bandgaps of group IIIA nitrides and their alloy nanocrystals can cover the region of 2.1–6.3 eV.

Self-supported patterns of oriented alignment of β-FeOOH nanowires are fabricated through a simple solution reaction from the complex [Fe(phen)3]²⁺ at 60 °C. The alignment of nanowires with a diameter of 40 nm and length of 6 μm is relatively uniform. HRTEM studies show that the growing direction of β-FeOOH nanowires is perpendicular to the orientation plane of self-formed β-FeOOH flake-like substrates. In the reaction and crystal growth process, the precursor [Fe(phen)3]²⁺ is undoubtedly vital to the formation of nanowire alignment. In detail, the formation of aligned nanowires is thought to be realized by controlling two competing reactions. Electrochemical and UV-visible measurements suggest that the product might have potential applications in lithium batteries and semiconductor electronics. This synthetic process is simple, mild, clean, reproducible, and free of any template; it provides a novel pathway for the low-temperature growth of nanowires and their simultaneous oriented alignment.

Self‐supported patterns of oriented alignment of β‐FeOOH nanowires are fabricated through a simple solution reaction from the complex [Fe(phen)3]2+at 60 °C. The alignment of nanowires with a diameter of 40 nm and length of 6 μm is relatively uniform. HRTEM studies show that the growing direction of β‐FeOOH nanowires is perpendicular to the orientation plane of self‐formed β‐FeOOH flake‐like substrates. In the reaction and crystal growth process, the precursor [Fe(phen)3]2+is undoubtedly vital to the formation of nanowire alignment. In detail, the formation of aligned nanowires is thought to be realized by controlling two competing reactions. Electrochemical and UV‐visible measurements suggest that the product might have potential applications in lithium batteries and semiconductor electronics. This synthetic process is simple, mild, clean, reproducible, and free of any template; it provides a novel pathway for the low‐temperature growth of nanowires and their simultaneous oriented alignment.

A new coordination-polymer-precursor route has been developed to synthesize nanowires under hydrothermal conditions. In the present work, well-aligned γ-MnO2 nanowires, growing along the [0 0 2] axis, have successfully been prepared by selecting an appropriate coordination polymer [{Mn(SO4)(4,4'-bpy)(H2O)2}n] as precursor. In comparison with the experimental results from other coordination-polymer precursors, it is found that only [{Mn(SO4)(4,4'-bpy)(H2O)2}n] is appropriate for the formation of γ-MnO2 crystal lattices during the process of oxidization. The IR absorption spectra of as-obtained precipitates at different reaction intervals minutely describe the reaction process, due to the different coordination abilities of ligands in the coordination polymer. More evidence about the mechanism will be further explored in the future study. Further observations show the ordered alignment of nanowires' tops and such well-aligned nanowires provide more possible applications in lithium batteries.

A new coordination‐polymer‐precursor route has been developed to synthesize nanowires under hydrothermal conditions. In the present work, well‐aligned γ‐MnO2nanowires, growing along the [0 0 2] axis, have successfully been prepared by selecting an appropriate coordination polymer [{Mn(SO4)(4,4′‐bpy)(H2O)2}n] as precursor. In comparison with the experimental results from other coordination‐polymer precursors, it is found that only [{Mn(SO4)(4,4′‐bpy)(H2O)2}n] is appropriate for the formation of γ‐MnO2crystal lattices during the process of oxidization. The IR absorption spectra of as‐obtained precipitates at different reaction intervals minutely describe the reaction process, due to the different coordination abilities of ligands in the coordination polymer. More evidence about the mechanism will be further explored in the future study. Further observations show the ordered alignment of nanowires' tops and such well‐aligned nanowires provide more possible applications in lithium batteries.

The methods of coordination chemistry are extended to fabricate hollow spheres of inorganic materials. In particular, in the present work a novel approach is successfully put forward to synthesize ZnO submicrometer hollow spheres, in which the coordination polymer Zn4,4′-bipyNCS2nwith a 1D chain structure is introduced as a reactant. In this approach, no additional template materials are needed to obtain submicrometer hollow-sphere structures in the reaction process. A possible mechanism is also proposed.

The methods of coordination chemistry are extended to fabricate hollow spheres of inorganic materials. In particular, in the present work a novel approach is successfully put forward to synthesize ZnO submicrometer hollow spheres, in which the coordination polymer [Zn(4,4'-bipy)(NCS)₂]_n with a 1D chain structure is introduced as a reactant. In this approach, no additional template materials are needed to obtain submicrometer hollow-sphere structures in the reaction process. A possible mechanism is also proposed.

Biomass aerogels have received extensive attention due to their unique natural characteristics. However, biomass-based chitosan aerogels are often confronted with the traditional issue concerning a weak skeleton structure, namely, the corresponding huge shrinkage for chitosan aerogels in the stage from the final gel to the aerogel. Herein, we put forward a new approach to enhance chitosan aerogels by introducing natural biomaterial cellulose nanocrystal (CNC). CNC is applied to connect/cross-link chitosan chains to form its networking construction through supramolecular interaction/physical entanglement, eventually realizing the enhancement of the chitosan aerogel network structure. Chitosan aerogels modified with CNC exhibit a high specific surface area of 578.43 cm2g–1, and the pore size distribution is in the range of 20–60 nm, which is smaller than the mean free path of gas molecules (69 nm), triggering a “no convection” effect. Hence, the gaseous heat transfer of chitosan aerogel is effectively suppressed. Chitosan aerogels with the addition of CNC show an excellent thermal insulation property (0.0272 W m-1K-1at ambient condition) and an enhanced compressive strength (0.13 MPa at a strain of 3%). This improvement method of chitosan aerogel in enhancing the skeleton structure aspect provides a new kind of idea for strengthening the nanoscale morphology structure of biomass aerogels.

Developing suitable catalysts capable of receiving injected electrons and possessing active sites for hydrogen evolution reaction (HER) is the key to building an efficient dye-sensitized system for hydrogen production. Fe3S4is generally regarded as an inferior HER catalyst among the metal sulfide family, mainly due to its weak surface adsorption toward H atoms. In this work, we demonstrate a facile metal–organic framework-derived method to synthesize uniform Fe3S4nanorods and active them for HER by Ni doping. Our experimental results and theoretical calculations reveal that Ni doping can greatly modify the electronic structure of Fe3S4nanorods, improving their electron conductivity and optimizing their surface adsorption energy toward H atoms. Sensitized by a commercial organic dye (eosin-Y), 1%Ni-doped Fe3S4nanorods display a high H2production rate of 3240 μmol gcat–1h–1with an apparent quantum yield of 12% under 500 nm wavelength, which is significantly higher than that of pristine Fe3S4and even higher than that of 1% Pt-deposited Fe3S4. The working mechanism of this dye-sensitized system is explored, and the effect of Ni-doping concentration has been studied. This work presents a facile strategy to synthesize metal-doped sulfide nanocatalysts with greatly enhanced activity toward photocatalytic H2production.

To improve user experience and allocate reasonably spectrum resources, the quality of experience (QoE) for user is introduced as an indicator to express the user's satisfaction with the service provided. The QoE‐driven resource allocation optimization algorithm for orthogonal frequency‐division multiple is designed to maximize the user's QoE and optimize resource allocation in vehicular cloud (VC) long‐term evolution (LTE) networks. Therein, a novel QoE model which reflects delay, transmission rate, and service price by mean opinion score (MOS) is proposed to identify different services. Furthermore, the characteristics of delay, transmission rate, and service price are also analyzed specifically at different time slots, respectively. Simulation results show that the proposed resource allocation algorithm could achieve a better QoE in the field of user satisfaction and throughput compared with other traditional algorithms, especially when the number of vehicles is greater than 30 or 22, respectively. Meanwhile, the impact of fairness on QoE and throughput are also improved apparently when the number of vehicles is small. In end, the QoE‐mode brings performance improvements on delay, transmission rate, and service price compared with other single X mode. To improve spectrum utilization efficiency and enhance the vehicle user satisfaction in vehicular LTE networks, we propose a spectrum resource allocation optimization algorithm, which is based on QoE‐driven related with delay, transmission rate, and service price. In this process, the concept of MOS as an indicator is introduced and further used to design QoE model. Meanwhile, the specific analysis on delay, transmission rate, and service price in different time slots is given out to indicate criterion of the spectrum resource obtained.

In this paper, we have developed a solution-phase template approach to synthesize Cu2S nanoribbons for the first time. Bi2S3nanoribbons act as both template and reactant when treated with small CuCl particles, generating Cu2S nanoribbons with the assistance of the solvent ethanol. Nanoribbons with different compositions of Bi2S3and Cu2S also could be obtained through controlling the reaction time. This kind of template method is expected to be a general template approach due to its slow reaction rate and simplicity.

A new type of hierarchical structure, a core-shell structure with spherically aligned nanorods, was prepared viaa simple room-temperature solution-based catalytic route in the case of α-MnO2.

α-Fe and γ-Fe₂O₃ nanowires were successfully synthesized from FeCl₂ solution with 1,10-phenanthroline as complexing reagent via a simple, mild reduction or reduction–oxidization process. It was found that there existed some folded ribbon-like nanostructures as well as nanowires in the obtained α-Fe and γ-Fe₂O₃ products. Magnetic behavior of as-prepared α-Fe and γ-Fe₂O₃ nanowires was investigated by the temperature dependence of magnetization. The formation mechanism of α-Fe and γ-Fe₂O₃ nanowires was also proposed.

A reverse micelle-assisted route was reported to prepare ZnO nanorods from two different precursors, Zn(NH3)42+and Zn(OH)42−, respectively. The reverse micelles were used as microreactors, which lead into anisotropic growth of ZnO crystals during a simple solvothermal process.

Carbon hollow spheres (400–600 nm) and vessels (400 nm × 3000 nm) have been synthesized from sp3-CCl₄ at 190 and 230 °C, respectively. The HRTEM images and Raman spectra reveal the sp2 nature of the as-obtained products, indicating that the transformation from carbon sp3 to sp2 occurs in the reactions. The possible mechanism has also been proposed.

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