The combination of excellent thermal stability and outstanding electrical performance is of great sig-nificance for piezoelectric ceramics.Herein,we have prepared 0.11Pb(In_(0.5)Nb_(0.5))O_(3)-0.89Pb(Hf_(0.47)Ti_(0.53...The combination of excellent thermal stability and outstanding electrical performance is of great sig-nificance for piezoelectric ceramics.Herein,we have prepared 0.11Pb(In_(0.5)Nb_(0.5))O_(3)-0.89Pb(Hf_(0.47)Ti_(0.53))O_(3)-Sb_(2)O_(5)(PIN-PHT-x Sb)ceramics by solid-phase method and investigated the effect of oxygen octahedral lattice distortion on microstructure and macroscopic electrical properties.The distortion index of oxygen octahedra is studied by Rietveld refinement,showing that optimal octahedral distortion can soften B-O repulsion,disrupt long-range ordered ferroelectric domains,and enhance local heterogeneities,signifi-cantly increasing piezoelectric properties.Moreover,outstanding thermal stability and ultrahigh piezo-electric response of PIN-PHT-1.2Sb ceramics are realized under the synergistic influence of octahedral distortion,excellent density,and large grain size.Compared with PIN-PHT ceramics,PIN-PHT-1.2Sb ce-ramics exhibit ultrahigh piezoelectric responses(d_(33)=706 pC/N,k_(p)=0.68,ε_(r)=3244),a high Curie temperature(T C)of 300℃,excellent thermal stability,and anti-fatigue properties.展开更多
利用溶剂热法,在N,N-二甲基甲酰胺(DMF)溶剂中共同还原乙酰丙酮铂(Pt(acac)2)和乙酰丙酮铜(Cu(acac)_2)制备PtCu八面体合金催化剂.PtCu_2八面体表现出明显的晶格收缩、较高比例的非氧化态Pt单质和较高的电子结合能,进而表现出较弱的含...利用溶剂热法,在N,N-二甲基甲酰胺(DMF)溶剂中共同还原乙酰丙酮铂(Pt(acac)2)和乙酰丙酮铜(Cu(acac)_2)制备PtCu八面体合金催化剂.PtCu_2八面体表现出明显的晶格收缩、较高比例的非氧化态Pt单质和较高的电子结合能,进而表现出较弱的含氧物种吸附强度和较低的d带中心位置.系统研究结构导向剂对PtCu合金形貌影响.在半电池测试中,由于PtCu_2具有均匀分散的规则八面体形貌结构,导致在0.9 V vs.RHE处氧还原(ORR)的质量比活性和面积比活性分别是Pt/C(JM)的6.3和27.2倍,并在加速衰减测试后其ORR的质量比活性仍达到Pt/C(JM)的4.5倍.展开更多
Electro-optical materials are crucial for lasers and modulators applications.Perovskite ferroelectric crystals,characterized by oxygen octahedrons and superior dipole migration capabilities,are recognized for their hi...Electro-optical materials are crucial for lasers and modulators applications.Perovskite ferroelectric crystals,characterized by oxygen octahedrons and superior dipole migration capabilities,are recognized for their high electro-optic coefficients.However,the application of perovskite ferroelectric crystals is often limited by reduced optical transparency,which results from light scattering and reflection at domain walls.In this study,we implemented a structure dimensionality reduction strategy to successfully transform a three-dimensional structure KNbO_(3)(KNO)crystal into a quasi-two-dimensional layered structure K_(3)Nb_(3)B_(2)O_(12)(KNBO)crystal through BO_(3)planar groups.This modification restricts the mobility of B-site ions within the layers while preserving significant spontaneous polarization along the interlayer direction,thus converting multipolar axis into a unipolar axis in the ferroelectric.This alteration in the direction of spontaneous polarization modifies the domain structure,thereby minimizing the scattering effects of the domain walls.As a result,the KNBO crystal exhibits a large effective electro-optic(EO)coefficient of 50.14 pm/V and a high transmittance exceeding 80%in the 330-2500 nm wavelength range.These properties surpass those of currently available commercial EO crystals.This research establishes a model for enhancing transparency and EO coefficient through structural design,offering potential applications to other EO crystals.展开更多
基金The authors would like to acknowledge the support of the National Ceramic Industry Design Institute of China(No.NICID2022Z02)the Instrumental Analysis Center of Xidian Uni-versity for providing test equipment,and also acknowledge the fi-nancial support of the Key Research and Development Program of Shaanxi(No.2022GY-184).
文摘The combination of excellent thermal stability and outstanding electrical performance is of great sig-nificance for piezoelectric ceramics.Herein,we have prepared 0.11Pb(In_(0.5)Nb_(0.5))O_(3)-0.89Pb(Hf_(0.47)Ti_(0.53))O_(3)-Sb_(2)O_(5)(PIN-PHT-x Sb)ceramics by solid-phase method and investigated the effect of oxygen octahedral lattice distortion on microstructure and macroscopic electrical properties.The distortion index of oxygen octahedra is studied by Rietveld refinement,showing that optimal octahedral distortion can soften B-O repulsion,disrupt long-range ordered ferroelectric domains,and enhance local heterogeneities,signifi-cantly increasing piezoelectric properties.Moreover,outstanding thermal stability and ultrahigh piezo-electric response of PIN-PHT-1.2Sb ceramics are realized under the synergistic influence of octahedral distortion,excellent density,and large grain size.Compared with PIN-PHT ceramics,PIN-PHT-1.2Sb ce-ramics exhibit ultrahigh piezoelectric responses(d_(33)=706 pC/N,k_(p)=0.68,ε_(r)=3244),a high Curie temperature(T C)of 300℃,excellent thermal stability,and anti-fatigue properties.
文摘利用溶剂热法,在N,N-二甲基甲酰胺(DMF)溶剂中共同还原乙酰丙酮铂(Pt(acac)2)和乙酰丙酮铜(Cu(acac)_2)制备PtCu八面体合金催化剂.PtCu_2八面体表现出明显的晶格收缩、较高比例的非氧化态Pt单质和较高的电子结合能,进而表现出较弱的含氧物种吸附强度和较低的d带中心位置.系统研究结构导向剂对PtCu合金形貌影响.在半电池测试中,由于PtCu_2具有均匀分散的规则八面体形貌结构,导致在0.9 V vs.RHE处氧还原(ORR)的质量比活性和面积比活性分别是Pt/C(JM)的6.3和27.2倍,并在加速衰减测试后其ORR的质量比活性仍达到Pt/C(JM)的4.5倍.
基金supported by the National Natural Science Foundation of China(52172009,52102011,12275274,52202011)the Science and Technology Project of Fujian Province(2021H0043)+3 种基金the Youth Cultivation Program of Chinese Academy of Sciences(JCPYJJ-22032)the Natural Science Foundation of Fujian Province(2023J01158)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2023317)the China Association for Science and Technology Young Elite Scientist Sponsorship Program by Cast(YESS20210304).
文摘Electro-optical materials are crucial for lasers and modulators applications.Perovskite ferroelectric crystals,characterized by oxygen octahedrons and superior dipole migration capabilities,are recognized for their high electro-optic coefficients.However,the application of perovskite ferroelectric crystals is often limited by reduced optical transparency,which results from light scattering and reflection at domain walls.In this study,we implemented a structure dimensionality reduction strategy to successfully transform a three-dimensional structure KNbO_(3)(KNO)crystal into a quasi-two-dimensional layered structure K_(3)Nb_(3)B_(2)O_(12)(KNBO)crystal through BO_(3)planar groups.This modification restricts the mobility of B-site ions within the layers while preserving significant spontaneous polarization along the interlayer direction,thus converting multipolar axis into a unipolar axis in the ferroelectric.This alteration in the direction of spontaneous polarization modifies the domain structure,thereby minimizing the scattering effects of the domain walls.As a result,the KNBO crystal exhibits a large effective electro-optic(EO)coefficient of 50.14 pm/V and a high transmittance exceeding 80%in the 330-2500 nm wavelength range.These properties surpass those of currently available commercial EO crystals.This research establishes a model for enhancing transparency and EO coefficient through structural design,offering potential applications to other EO crystals.
