Search

The photovoltaic effect driven by ferroelectric polarization shows great application potential in photovoltaic devices. Two-dimensional (2D) Ruddlesden–Popper perovskite molecular ferroelectric materials, which combine adjustable structure, polarization, and low band gap properties, occupy a promising position in this field. However, most of the studies on molecular ferroelectrics reported in the literature focus on single crystals, while there are few reports on thin film devices. In this paper, 2D EA2MA2Pb3Br10 (EA = ethylammonium, MA = methylammonium) molecular ferroelectric materials are used to prepare molecular ferroelectric photovoltaic devices, and polarization-driven controllable photovoltaic devices are successfully realized. Under the irradiation of standard sunlight, the device exhibits a significant photovoltaic effect, and its short-circuit current density reaches the order of mA/cm2, which is much higher than that of ordinary inorganic ferroelectrics. In addition, by applying an external electric field, the photovoltaic performance of the device can be significantly improved, and multilevel regulation can be achieved. The results provide a viable method for developing polarization-driven tunable photovoltaic devices based on 2D molecular ferroelectrics. [ABSTRACT FROM AUTHOR]

Phosphors for near-ultraviolet (NUV)-triggered white light-emitting diodes (LEDs) have become an attractive research topic in recent years. However, it is still difficult for phosphors to have simultaneous high luminous intensity, superior color purity, and excellent thermal stability. Hence, a series of Eu3+-activated alkali rare-earth double-tungstate nanoparticles with high luminescence intensity were prepared by a facile hydrothermal reaction method. The influence of rare-earth ions and alkali cations on the luminescence properties was investigated. Impressively, the prepared phosphors exhibit superior color purity and excellent thermal stability. Meanwhile, the emission intensity and color purity can be controlled by tuning the concentrations of Eu3+ ions. By employing the resultant nanoparticles, a fabricated LED device emitted bright warm white light with a high color rendering index (CRI) of 92.12 and a suitable correlated color temperature (CCT) of 4689 K. This work straightly confirms that the prepared phosphors are promising candidates as red-emitting components applied in NUV-triggered indoor illumination. [ABSTRACT FROM AUTHOR]

Continuous accumulation of nitrate in water will lead to the imbalance of the nitrogen cycle in nature, which brings about great threat to the human health and social environment. Therefore, it is urgent to develop a simple and effective technology to repair nitrate-polluted water. Due to the rapid development of nanomaterials, electrocatalytic nitrate reduction technology has been widely used. Among them, iron-based materials with low price and high catalytic activity are in high demand. Herein, we report a highly active zero-valence iron@periodic mesoporous organosilicon (Fe@PMO) nanocomposite with spherical Fe nanoparticles as the basic structural unit and phenylene-bridged mesoporous organosilica as silicon and carbon sources. PMO shows the characteristic of a rigid organic–inorganic hybrid skeleton, which plays an important role in the spatial confinement of Fe nanoparticles and avoids the corrosion of the electrolyte to the active sites in the process of electrocatalysis. The obtained Fe@PMO catalyst exhibits an excellent nitrate conversion efficiency of 90% and a nitrogen selectivity of 99%. This study provides an innovative strategy to construct efficient electrocatalysts for nitrate reduction. [ABSTRACT FROM AUTHOR]

Despite the high theoretical capacity of the sodium–sulfur battery, its application is seriously restrained by the challenges due to its low sulfur electroactivity and accelerated shuttle effect, which lead to low accessible capacity and fast decay. Herein, an elaborate carbon framework, interconnected mesoporous hollow carbon nanospheres, is reported as an effective sulfur host to achieve excellent electrochemical performance. Based onin situsynchrotron X-ray diffraction, the mechanism of the room temperature Na/S battery is proposed to be reversible reactions between S8and Na2S4, corresponding to a theoretical capacity of 418 mAh g–1. The cell is capable of achieving high capacity retention of ∼88.8% over 200 cycles, and superior rate capability with reversible capacity of ∼390 and 127 mAh g–1at 0.1 and 5 A g–1, respectively. [ABSTRACT FROM AUTHOR]

A kindof novel uniform monodispersed three-dimensional dendriticmesoporous silica nanospheres (3D-dendritic MSNSs) has been successfullysynthesized for the first time. The 3D-dendritic MSNSs can have hierarchicalmesostructure with multigenerational, tunable center-radial, and dendriticmesopore channels. The synthesis was carried out in the heterogeneousoil–water biphase stratification reaction system, which allowedthe self-assembly of reactants taking place in the oil–waterinterface for one-pot continuous interfacial growth. The average poresize of each generation for the 3D-dendritic MSNSs can be adjustedfrom 2.8 to 13 nm independently, which can be controlled by the variedhydrophobic solvents and concentration of silica source in the upperoil phase. The thickness of each generation can be tuned from ∼5to 180 nm as desired, which can be controlled by the reaction timeand amount of silica source. The biphase stratification approach canalso be used to prepare other core–shell and functional mesoporousmaterials such as Au nanoparticle@3D-dendritic MSNS and Ag nanocube@3D-dendriticMSNS composites. The 3D-dendritic MSNSs show their unique advantagefor protein loading and releasing due to their tunable large poresizes and smart hierarchical mesostructures. The maximum loading capacityof bovine β-lactoglobulin with 3D-dendritic MSNSs can reachas high as 62.1 wt % due to their large pore volume, and the simulatedprotein releasing process can be tuned from 24 to 96 h by flexiblemesostructures. More importantly, the releasing rates are partly dependenton the hierarchical biodegradation, because the 3D-dendritic MSNSswith larger pore sizes have faster simulated biodegradation ratesin simulated body fluid. The most rapid simulated biodegradation canbe finished entirely in 24 h, which has been greatly shortened thantwo weeks for the mesoporous silica reported previously. As the inorganicmesoporous materials, 3D-dendritic MSNSs show excellent biocompatibility,and it would have a hopeful prospect in the clinical applications. [ABSTRACT FROM AUTHOR]

In this work, we have successfullydeveloped a novel multifunctionalnear-infrared (NIR)-stimulus controlled drug release system basedon gold nanocages as photothermal cores, mesoporous silica shellsas supporters to increase the anticancer drug loading and thermallyresponsive poly(N-isopropylacrylamide) (PNIPAM) asNIR-stimuli gatekeepers (Au-nanocage@mSiO2@ PNIPAM). Theunique Au-nanocage@mSiO2nanocarrier was elaborately fabricatedby utilizing yolk-shell Ag-nanocube@mSiO2nanostructureas a template by means of spatially confined galvanic replacement.The Au nanocage cores can effectively absorb and convert light toheat upon irradiation with a NIR laser, resulting in the collapseof the PNIPAM shell covering the exterior of mesoporous silica, andexposes the pores of mesoporous silica shell, realizing the triggeredrelease of entrapped DOX drugs. The in vitro studies have clearlydemonstrated the feasibility and advantage of the novel nanocarriersfor remote-controlled drug release systems. [ABSTRACT FROM AUTHOR]

Degradation of polyolefin (PE) plastic by a traditional chemical method requires a high pressure and a high temperature but generates complex products. Here, sulfur vacancy-rich ZnIn 2 S 4 and hydroxy-rich ZnIn 2 S 4 were rationally fabricated to realize photocatalytic degradation of PE in an aqueous solution under mild conditions. The results reveal that the optimized photocatalyst could degrade PE into CO 2 and CO, and PE had a weight loss of 84.5% after reaction for 60 h. Systematic experiments confirm that the synergetic effect of hydroxyl groups and S vacancies contributes to improve the photocatalytic degradation properties of plastic wastes. In-depth investigation illustrates that the active radicals attack (h + and •OH) weak spots (C-H and C-C bonds) of the PE chain to form CO 2 , which is further selectively photoreduced to CO. Multimodule synergistic tandem catalysis can further improve the utilization value of plastic wastes; for example, product CO 2 /CO in the plastic degradation process can be converted in situ into HCOOH by coupling with electrocatalytic technology.

Metal sulfides (MSs) can efficiently entrap thiophilic components, such as elemental mercury (Hg 0 ), and realize environmental remediation. However, there is still a critical problem challenging the extensive application of MSs in related areas, i.e., how to self-regulate their water (H 2 O) resistance without complexing the sorbent preparation procedure. This work for the first time developed an in situ acid-etching method that self-engineered the water affinity of MSs through changing the interfacial interaction between MSs and Hg 0 /H 2 O. The introduction of abundant, undercoordinated sulfur onto the sorbent surface was the primary reason accounting for the significantly improved H 2 O resistance. The high surface coverage of undercoordinated sulfur induced the formation of polysulfur chains (S x 2- ) that stabilized Hg 0 via a bridging bond and repelled H 2 O, attributed to the favorable electron configurations. These properties made the surface of MSs highly hydrophobic and increased the adsorption selectivity toward Hg 0 over H 2 O. The MSs exhibited 100% H 2 O resistance even in the presence of 20% H 2 O, which is much higher than the H 2 O concentration under most practical scenarios. From these perspectives, this work for the first time overcame the detrimental effects of H 2 O on MSs through a self-regulating way that is scalable and negligibly complexes the sorbent preparation pathway. The highly water-resistant and cost-effective MSs as prepared can serve as efficient Hg 0 removal from industrial flue gas in the future.