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NaNbO3-based ceramics usually show ferroelectric-like P-E loops at room temperature due to the irreversible transformation of the antiferroelectric orthorhombic phase to ferroelectric orthorhombic phase, which is not conducive to energy storage applications. Our previous work found that incorporating CaHfO3 into NaNbO3 can stabilize its antiferroelectric phase by reducing the tolerance factor (t), as indicated by the appearance of characteristic double P-E loops. Furthermore, a small amount of MnO2 addition effectively regulate the phase structure and tolerance factor of 0.94NaNbO3-0.06CaHfO3 (0.94NN-0.06CH), which can further improve the stability of antiferroelectricity. The XRD and XPS results reveal that the Mn ions preferentially replace A-sites and then B-sites as increasing MnO2. The antiferroelectric orthorhombic phase first increases and then decreases, while the t shows the reversed trend, thus an enhanced antiferroelectricity and the energy storage density Wrec of 1.69 J/cm3 at 240 kV/cm are obtained for 0.94NN-0.06CH-0.5%MnO2(in mass fraction). With the increase of Mn content to 1.0% from 0.5%, the efficiency increases to 81% from 45%, although the energy storage density decreases to 1.31 J/cm3 due to both increased tolerance factor and non-polar phase.

Room-temperature thermoelectric materials provide promising solutions for energy harvesting from the environment, and deliver a maintenance-free power supply for the internet-of-things (IoTs). The currently available Bi2Te3 family discovered in the 1950s, still dominates industrial applications, however, it has serious disadvantages of brittleness and the resource shortage of tellurium (1 × 10−3 ppm in the earth's crust). The novel Mg3Sb2 family has received increasing attention as a promising alternative for room-temperature thermoelectric materials. In this review, the development timeline and fabrication strategies of the Mg3Sb2 family are depicted. Moreover, an insightful comparison between the crystallinity and band structures of Mg3Sb2 and Bi2Te3 is drawn. An outlook is presented to discuss challenges and new paradigms in designing room-temperature thermoelectric materials.

F-BT-xNT MLCCs were designed and expected to achieve high energy-storage density because of ultrahigh Ps value of BiFeO3 system. With enhancement of ionic bonding and dielectric relaxation, excellen Urec = 9.1 J cm−3 and η > 80% were achieved at x = 0.12.

The flavoring agent dihydrocoumarin suppressed IgE-induced mast cell activation via down-regulating MAPK, NF-κB and AP-1 pathways. Dihydrocoumarin may represent a novel MC-suppressing strategy for the treatment of IgE-mediated allergic diseases.

The enhanced piezoelectric and ferroelectric properties of the tetragonal 0.67BiFeO3–0.33BaTiO3 (BF–33BT) ceramics without MnO2 doping or other dopants via tailoring sintering temperature (TS) and dwell time (td) are reported. All ceramics crystallized in a single tetragonal phase, independent of the adopted TS and td. As the TS or td is increased, the BF–33BT ceramics show an increase in grain size and in relative density, while TS > 980 °C or td > 6 h would result in more oxygen vacancies caused by Bi3+ evaporation and/or reduction of Fe3+ to Fe2+, along with a reduced relative density and an increased current leakage density. Because of the increased grain size, the higher relative density, and relatively less oxygen vacancies, high d33 = 151 pC/N and Pr = 25.9 μC/cm2 were achieved in tetragonal BF–33BT ceramics with TS = 980 °C and td = 6 h. In addition, large unipolar strain of 0.146% and $$d_{33}^{*}$$ =326 pm/V (40 kV/cm), as well as high TC = 427 °C were also obtained in the BF–33BT ceramics with TS = 980 °C and td = 6 h. Our studies indicate that the grain size, the relative density, and the oxygen vacancies play important roles for the piezoelectric properties of BF–33BT ceramics.

Ferroelectric perovskite oxides exhibit the bulk photovoltaic effect, which enables an above-bandgap photovoltage, controllable photocurrent response, and higher efficiencies. Herein, the phase structure, ferroelectric, dielectric, light absorption, and photovoltaic properties in (Ba0.95Ca0.05)(Ti0.92Sn0.08-xZrx)O3 (BCTSZx) ceramics were investigated. All BCTSZx samples had good ferroelectric properties along with a narrow band gap (Eg = 2.53–2.60 eV). A large photovoltaic response under AM 1.5 G simulated sunlight was observed in the poled BCTSZ0.06 ceramics, in which the maximum short-circuit current (JSC = 3.66 nA cm−2) as well as the highest transient current (JTC = 32.56 nA cm−2) and photocurrent (JPC = 12.63 nA cm−2) were obtained in 500 μm-thick sample negatively poled at 30 kV cm−1. Our results deepen an understanding of the ferroelectric photovoltaic mechanism of perovskite materials and provide a new material for photovoltaic and multifunctional applications.

Digenite (Cu1.8S) as a potential p-type thermoelectric (TE) material has attracted extensive attention due to its environmental benign, abundant resources and low cost of component elements. In this study, the TE properties of MnxCu1.8S bulk samples prepared by mechanical alloying (MA) combined with spark plasma sintering (SPS) were investigated. Doping Mn would initially substitute Cu and tune the band structure of Cu1.8S with an enlarged band gap Eg. However, if Mn content is beyond the solubility limit of x = 0.01 in Cu1.8S will cause the formation of MnS, which contributes to the formation of Cu-rich phases at 0.02 ≤ x ≤ 0.08. Benefiting from the synergetic scattering effect of point defects ( Mn Cu • , V S • • ) and MnS, Cu1.96S, Cu1.97S, Cu2S phases, the lowest thermal conductivity κ value of 0.75 W m−1K−1 was obtained at 773 K for Mn0.08Cu1.8S. Along with the decreased κ, the highest figure of merit ZT value of 0.92 at 773 K achieved in Mn0.08Cu1.8S bulk sample. A maximum engineering ZTeng of 0.3 and its efficiency ηmax of about 6% were obtained at 323–773 K, which is almost 3 times than that of the pristine Cu1.8S (ηmax = 2.2%). Introducing Mn in Cu1.8S is an effective and convenient strategy to improve TE performance.

The relaxor behaviors near the morphotropic phase boundary (MPB) can reduce the energy barrier for polarization rotation, which is an effective strategy to improve the piezoelectric properties of materials. In this work, the phase structure, microstructure, and piezoelectric properties of (0.69-x)Bi1.02FeO3-0.31BaTiO3-xBi(Mg1/2Ti1/2)O3 (0.00 ≤ x ≤ 0.08) ceramics were systematically studied. The addition of a tiny amount of Bi(Mg1/2Ti1/2)O3 was found to cause the phase to transform from R-phase-dominant ferroelectrics (FEs) to PC-phase-dominant relaxor ferroelectrics (RFEs). The dielectric and electrical data reveal that nonergodic relaxor ferroelectrics (NE-RFEs) near the MPB were favorable for domain switching, which contributed to the enhanced piezoelectric and electrostrain properties of d33 = 182 pC/N, TC = 475 °C, and S = 0.21% at x = 0.04. Finally, a model of domain growth induced by an electric field was proposed for FEs and NE-RFEs.

ZnO is a promising high-temperature thermoelectric material because of its non-toxicity and low-cost. However, the wide band gap and low electrical conductivity lead to inferior thermoelectric properties. Herein, C-doping in ZnO bulk was achieved by the pyrolysis of hydrothermal surfactant TEA through a facile and speedy SPS technique. DFT calculation and experimental results show that C was incorporated into the O-site in ZnO, which reduces band gap and increases carrier concentration, thereby improving electrical conductivity and power factor. Meanwhile, the additional point defects introduced by the substitution of C/O atoms strengthen phonon scattering and decrease thermal conductivity. Benefiting from C-doping via not only tuning the electrical transport properties but also reducing the thermal conductivity, a peak ZT value of 0.024 at 773 K was achieved for Zn(O,C) bulk. It indicates that C-doping in ZnO is an effective and convenient strategy to improve thermoelectric performance.

Insulin-like growth factor-1 (IGF-1) is a neurotrophic factor produced locally in the central nervous system which can promote axonal regeneration, protect motoneurons, and inhibit neuroinflammation. In this study, we used the zebrafish spinal transection model to investigate whether IGF-1 plays an important role in the recovery of motor function. Unlike mammals, zebrafish can regenerate axons and restore mobility in remarkably short period after spinal cord transection. Quantitative real-time PCR and immunofluorescence showed decreased IGF-1 expression in the lesion site. Double immunostaining for IGF-1 and Islet-1 (motoneuron marker)/GFAP (astrocyte marker)/Iba-1 (microglia marker) showed that IGF-1 was mainly expressed in motoneurons and was surrounded by astrocyte and microglia. Following administration of IGF-1 morpholino at the lesion site of spinal-transected zebrafish, swimming test showed retarded recovery of mobility, the number of motoneurons was reduced, and increased immunofluorescence density of microglia was caused. Our data suggested that IGF-1 enhances motoneuron survival and inhibits neuroinflammation after spinal cord transection in zebrafish, which suggested that IGF-1 might be involved in the motor recovery.

BiFeO3-BaTiO3 is a promising high-temperature piezoelectric ceramic that possesses both good electromechanical properties and a Curie temperature (TC). Here, the piezoelectric charge constants (d33) and strain coefficients (d*33) of (1 - x)BiFeO3-xBaTiO3 (BF-xBT; 0.20 ≤ x ≤ 0.50) lead-free piezoelectrics were investigated at room temperature. The results showed a maximum d33 of 225 pC/N in the BF-0.30BT ceramic and a maximum d*33 of 405 pm/V in the BF-0.35BT ceramic, with TCs of 503 and 415 °C, respectively. To better understand the performance enhancement mechanisms, a phase diagram was established using the results of XRD, piezoresponse force microscopy, TEM, and electrical property measurements. The superb d33 of the BF-0.30BT ceramic arose because of its location in the optimum point in the morphotropic phase boundary, low oxygen vacancy (VO··) concentration, and domain heterogeneity. The superior d*33 of the BF-0.35BT ceramic was attributed to a weak relaxor behavior between coexisting macrodomains and polar nanoregions. The presented strategy provides guidelines for designing high-temperature BF-BT ceramics for different applications.

Adsorption and photocatalytic oxidation are promising technologies for eliminating antibiotics (e.g. tetracycline) in aquatic environments. However, traditional powdery nanomaterials are limited by drawbacks of difficult separation and lack of synergistic function, which do not conform to the practical demand. Herein, we developed a simple one-step gelation-pyrolysis route to fabricate hydrophilic three-dimensional (3D) porous photocatalytic adsorbent, in which CuO nanoparticles are uniformly and firmly embedded in nitrogen-doped (N-doped) porous carbon frameworks. The obtained N-doped carbon/CuO bulky composites exhibited excellent ability to adsorb tetracycline hydrochloride (TC), which was subsequently photo-oxidized under visible light. Their hydrophilic nature favors the adsorption processes toward TC, with a maximum adsorption capacity reaching 25.03 mg∙g−1. In addition, >94.4% of TC molecules could be photo-degraded in 4 h with good cycling efficiency after three consecutive tests. Finally, a reaction scheme for removal process of TC was proposed. The obtained 3D porous N-doped carbon/CuO nanocomposites show great promise for efficient removal of antibiotics in aqueous solution by synergistically utilizing adsorption and photocatalytic oxidation processes.

It is challenging for material chemists to develop lead-free ceramics due to the toxicity of lead for human health and environment. (Ba, Ca)(Ti, Zr)O3 and (Ba, Ca)(Ti, Sn)O3 lead-free piezoelectric ceramics have attracted much attention due to their superior piezoelectric properties. In this study, Ca2+, Zr4+ and Sn4+ were simultaneously doped at A-sites and B-sites, respectively, to clarify the structure and enhance the electrical performance. (Ba1−xCax)(Ti0.94Zr0.01Sn0.05)O3 (BCxTZS) lead-free piezoelectric ceramics were successfully fabricated by conventional solid-state reactive sintering method. The effects of Ca2+ content (x) and sintering temperature on microstructure, phase structure and electrical properties of BCxTZS were investigated. Herein, BCxTZS ceramics are the coexistence of R-O phases as 0.01 ≤ x ≤ 0.02, and they become O-T phases as 0.02

Cu1.8S has been considered as a potential thermoelectric (TE) material for its stable electrical and thermal properties, environmental benignity, and low cost. Herein, the TE properties of nanostructured Cu1.8S1−xTex (0 ⩽ x ⩽ 0.2) bulks fabricated by a facile process combining mechanical alloying (MA) and room-temperature high-pressure sintering (RT-HPS) technique were optimized via eliminating the volatilization of S element and suppressing grain growth. Experimentally, a single phase of Cu1.8S was obtained at x = 0, and a second Cu1.96S phase formed in all Cu1.8S1−xTex samples when 0.05 ⩽ x ⩽ 0.125. With further increasing x to 0.15 ⩽ x ⩽ 0.2, the Cu2−zTe phase was detected and the samples consisted of Cu1.8S, Cu1.96S, and Cu2−zTe phases. Benefiting from a modified band structure and the coexisted phases of Cu1.96S and Cu2−zTe, the power factor is enhanced in all Cu1.8S1−xTex (0.05 ⩽ x ⩽ 0.2) alloys. Combining with a drastic decrease in the thermal conductivity due to the strengthened phonon scatterings from multiscale defects introduced by Te doping and nano-grain boundaries, a maximum figure of merit (ZT) of 0.352 is reached at 623 K for Cu1.8S0.875Te0.125, which is 171% higher than that of Cu1.8S (0.130). The study demonstrates that doping Te is an effective strategy to improve the TE performance of Cu1.8S based materials and the proposed facile method combing MA and RT-HPS is a potential way to fabricate nanostructured bulks.

The abnormal production of short chain fatty acid (SCFAs) caused by gut microbial dysbiosis plays an important role in the pathogenesis and progression of Parkinson’s disease (PD). This study sought to evaluate how butyrate, one of SCFAs, affect the pathology in a subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) treated mouse model of PD. Sodium butyrate (NaB; 165 mg/kg/day i.g., 7 days) was administrated from the day after the last MPTP injection. Interestingly, NaB significantly aggravated MPTP-induced motor dysfunction (P

Antiferroelectric materials are attractive for energy storage applications and are becoming increasingly important for power electronics. Lead-free silver niobate (AgNbO3) and sodium niobate (NaNbO3) antiferroelectric ceramics have attracted intensive interest as promising candidates for environmentally friendly energy storage products. This review provides the fundamental background of antiferroelectricity with an introduction to the definition of antiferroelectricity, historical research evolution of antiferroelectric materials, and some advanced techniques for structural characterization. Meanwhile, recent progress on lead-free antiferroelectric ceramics, represented by AgNbO3 and NaNbO3, is highlighted in terms of their crystal structures, phase transitions and potential dielectric energy storage applications. Specifically, the origin of the enhanced energy storage performance is discussed from a scientific point of view. The modification approaches are then summarized for the development of new strategies to further improve the energy storage performance. This article concludes with a discussion of the remaining challenges and opportunities for further development of lead-free antiferroelectrics.

Excess Bi was added to 0.7Bi1+xFeO3-0.3BaTiO3 (B1+xF-0.3BT; x = 0.00–0.05) ceramics to compensate for the volatilization of Bi2O3 during sintering. The domain structure and the domain switching of the B1+xF-0.3BT ceramics were systematically studied by the characterization of electrical properties and the use of piezoresponse force microscopy (PFM) and transmission electron microscopy (TEM). XRD patterns showed that the phase structure of all of the ceramics was in the morphotropic phase boundary (MPB), consisting of rhombohedral and pseudocubic phases. Appropriate compensation with Bi content can promote domain switching due to the precise control of MPB, which plays a vital role in obtaining high piezoelectric properties. Therefore, the outstanding piezoelectric properties of d33 = 214 pC/N, TC = 528 °C, kp = 0.325 and Sp-p = 0.375% were obtained in B1.02F-0.3BT ceramics, the properties of which are superior to those obtained in previously reported studies of BF-BT based ceramics. The present investigation of the compensating Bi content will inspire further research to develop BF-BT based ceramics suitable for practical use.

Pores in a solid can effectively reduce thermal conduction, but they are not favored in thermoelectric materials due to simultaneous deterioration of electrical conductivity. Conceivably, creating a porous structure may endow thermoelectric performance enhancement provided that overwhelming reduction of electrical conductivity can be suppressed. This work demonstrates such an example, in which a porous structure is formed leading to a significant enhancement in the thermoelectric figure of merit (zT). By a unique BiI

We reported a facile analysis and reduction of oxygen vacancy ( V O • • ) in 0.7Bi(Fe1-xScx)O3-0.3BaTiO3 (0≤x≤0.08) ceramics. The leakage current mechanism was investigated intensively. Our results indicated that oxygen vacancies are the main cause for the high conductivity in BF-BT ceramics, and their concentration was quantitatively estimated from the Bi3+ content and the average oxidation state of iron. The V O • • concentration was effectively suppressed and the insulation resistance was enhanced by almost two orders of magnitude after doping 2%mol Sc3+. The enhanced insulation resistance contributed to excellent piezoelectric properties with d33 = 165 pC/N, TC = 505 °C, and kp = 26%. The proposed analysis method used to quantify the V O • • concentration provides valuable indications to reduce the leakage current density and improve the piezoelectric properties of BF-BT based ceramic.

Herein, nano-BaTiO3/Bi2O3/Fe2O3 and BaCO3/TiO2/Bi2O3/Fe2O3 were respectively used to prepare 0.7BiFeO3-0.3BaTiO3 (0.7BF-0.3BT) ceramics by conventional solid-state method and clarify the reaction path, phase structure, microstructure, ferroelectric, and piezoelectric properties. 0.7BF-0.3BT ceramic using nano-BaTiO3 with cubic phase (CBT) undergoes the formation of rhombohedral α-phase (Rα) and the transition from Rα and CBT to rhombohedral β-phase (Rβ) and pseudo-cubic (PC) phases, while the counterpart using BaCO3/TiO2 directly generates Rβ and PC. Nano-BaTiO3 can decrease pores and oxygen vacancies in the resultant ceramics comparing to BaCO3/TiO2, which is due to an inhibited decomposition of Rα and a weaker reduction of Fe3+ to Fe2+, leading to increased density and reduced leakage current density. Benefitting from a proper phase ratio, increased density and reduced leakage current density, the enhanced piezoelectric properties d33 = 210 pC/N, kp = 0.34, Pr = 31.2 μC/cm2 and TC = 514 °C are obtained in 0.7BF-0.3BT ceramic using nano-BaTiO3. Our work reveals the importance of raw materials and the potential of BF-BT as a high-temperature lead-free piezoelectric ceramic material.