High-performance piezoelectric materials , whose displacement is sensitive to an external field and vice versa, are constantly required in electromechanical applications. Here, we introduce Nd 3+ ions into 0.49Pb(Nb 2/3 Ni 1/3 )O 3 -0.51Pb(Hf 0.3 Ti 0.7 )O 3 (PNN-PHT) ceramics via the solid-state method. By constructing a ferroelectric system in the morphotropic phase boundary region and exploiting the synergistic effect of polar nanoregions and an enhanced local structural heterogeneity, excellent piezoelectricity and dielectric properties are obtained. The optimized piezoelectric coefficient d 33 , dielectric constant ε 33 , electromechanical coupling factor k p , and dielectric loss tanδ are 1125 pC/N, 8667, 0.66 %, and 1.94 %, respectively. The Vogel-Fulcher law and relaxation analysis were adopted to understand the origin of the high piezoelectricity. The Rayleigh analysis method was used to study the intrinsic and extrinsic contributions to the piezoelectricity of the Nd-doped PNN-PHT ceramics, the extrinsic contribution was found to be up to 19 % in the optimal region (PNN-PHT + 0.4 at. % Nd 2 O 3 ). Moreover, according to in-situ ferroelectric measurements and fatigue measurements, the PNN-PHT + 0.4 at. % Nd 2 O 3 ceramic exhibits excellent fatigue resistance and stable piezoelectric behavior at 60 ℃ . This work provides an approach to realize high-performance piezoelectric ceramics with good electromechanical stability under external condition, which is expected to expand the range of application of piezoelectric materials, e.g., for transducers.
The sustainable production of carbamates from biomass-derived molecules provides a viable alternative to petrochemical-based production routes. In this work, we reported an efficient catalytic strategy for synthesizing bio-based furfurylmethyl carbamate (FMC) through methoxycarbonylation of furfurylamine with dimethyl carbonate (DMC) under mild conditions. A novel Pb-Ni composite oxide catalyst with high activity and stability was developed, which significantly outperformed conventional monometallic oxide catalysts. Comprehensive characterization revealed that the synergistic interaction between Pb and Ni species constructed composite oxide nanoparticles (about 11.4 nm), with Pb species highly dispersed on the NiO matrix. Consequently, highly defective structure, abundant acid-base dual sites, and a high specific surface area were concurrently formed, which were identified as critical factors for activating both nucleophilic and electrophilic reactants. Significantly, appreciable quantities of furfuryl isocyanate were detected, demonstrating the feasibility of a one-pot cascade synthesis of bio-based isocyanates from amines and DMC.
Modern electronic devices are highly in demand for high-performance piezoelectric materials. Herein, Pb(Ni, Nb)O3–Pb(Lu, Nb)O3–PbTiO3 piezoelectric ceramics are investigated, among which the 0.52PNN–0.16PLN–0.32PT ceramic shows the best performance (d33 = 850 pC N−1, d33* = 1139 pm V−1). Excellent piezoelectricity can be explained by multiphase coexistence, as well as an enhanced local heterogeneous structure. Polar nanoregions that promote polarization rotation are an important cause of high piezoelectricity according to characterization using SEM and PFM. TEM also confirmed a heterogeneous domain configuration with two coexisting phases. In addition, a large signal piezoelectricity of 1000 pm V−1 is maintained in the temperature range of 20–90 °C. This work presents an excellent example of achieving both high piezoelectric properties and a good temperature range in relaxor ferroelectric ceramics.
危险品化学品经营许可证（带存储）