Epitaxial Mn_(4)N films with different thicknesses were fabricated by facing-target reactive sputtering and their anomalous Hall effect(AHE)is investigated systematically.The Hall resistivity shows a reversed magnetic...Epitaxial Mn_(4)N films with different thicknesses were fabricated by facing-target reactive sputtering and their anomalous Hall effect(AHE)is investigated systematically.The Hall resistivity shows a reversed magnetic hysteresis loop with the magnetic field.The magnitude of the anomalous Hall resistivity sharply decreases with decreasing temperature from300 K to 150 K.The AHE scaling law in Mn_(4)N films is influenced by the temperature-dependent magnetization,carrier concentration and interfacial scattering.Different scaling laws are used to distinguish the various contributions of AHE mechanisms.The scaling exponentγ>2 for the conventional scaling in Mn_(4)N films could be attributed to the residual resistivityρ_(xx0).The longitudinal conductivityσ_(xx)falls into the dirty regime.The scaling ofρ_(AH)=αρ_(xx0)+bρ_(xx)~nis used to separate out the temperature-independentρ_(xx0)from extrinsic contribution.Moreover,the relationship betweenρ_(AH)and pxx is fitted by the proper scaling to clarify the contributions from extrinsic and intrinsic mechanisms of AHE,which demonstrates that the dominant mechanism of AHE in the Mn4 N films can be ascribed to the competition between skew scattering,side jump and the intrinsic mechanisms.展开更多
The magnetic and electronic transport properties manipulated by spin-orbit torque have been devoted much attention as they show a great promise for future spintronic devices.Here,the spin dependent transport propertie...The magnetic and electronic transport properties manipulated by spin-orbit torque have been devoted much attention as they show a great promise for future spintronic devices.Here,the spin dependent transport properties of the facing-target sputtered Pt/Mn_(4)N bilayers on MgO(001)substrates have been investigated systematically.The Hall resistivity of Pt/Mn_(4)N bilayers is strongly dependent on temperature,applied current intensity,Mn_(4)N and Pt layer thicknesses.The temperature-dependent sign reversal of anomalous Hall resistivity appears in Pt/Mn_(4)N bilayers,which is dominated by the competition between the magnetic proximity and spin Hall effects.Besides,the magnitude of anomalous Hall resistivity can be manipulated by applied current density.The critical and saturation currents are related to Mn_(4)N and Pt layer thicknesses.Furthermore,a Dzyaloshinskii-Moriya interaction coefficient(D)of 5.63 mJ·m^(-2)is calculated in Pt/Mn_(4)N/MgO systems.The details of the anomalous Hall effects in Pt/Mn_(4)N bilayers are helpful to understand the interfacial effects between heavy metals and ferrimagnets.展开更多
This study aimed to prepare and apply a novel Pt/CdMoO_(4) composite photocatalyst for photocatalytic N2 fixation and tetracycline degradation. The Pt/CdMoO_(4) composite was subjected to comprehensive investigation o...This study aimed to prepare and apply a novel Pt/CdMoO_(4) composite photocatalyst for photocatalytic N2 fixation and tetracycline degradation. The Pt/CdMoO_(4) composite was subjected to comprehensive investigation on the morphology, structure, optical properties, and photoelectric chemical properties. The results demonstrate the dispersion of Pt nanoparticles on the CdMoO_(4) surface. Close contact between CdMoO_(4) and Pt was observed, resulting in the formation of a heterojunction structure at their contact region. Density functional theory calculation and Mott-Schottky analysis revealed that Pt possesses a higher work function value than CdMoO_(4), resulting in electron drift from CdMoO_(4) to Pt and the formation of a Schottky barrier. The presence of this barrier increases the separation efficiency of electron-hole pairs, thereby improving the performance of the Pt/CdMoO_(4) composite in photocatalysis. When exposed to simulated sunlight, the optimal Pt/CdMoO_(4) catalyst displayed a photocatalytic nitrogen fixation rate of 443.7 μmol·L‒^(1)·g‒^(1)·h‒^(1), which is 3.2 times higher than that of pure CdMoO_(4). In addition, the composite also exhibited excellent performance in tetracycline degradation, with hole and superoxide species identified as the primary reactive species. These findings offer practical insights into designing and synthesizing efficient photocatalysts for photocatalytic nitrogen fixation and antibiotics removal.展开更多
将小分子金属配合物[Pt(C^N^N)Cl](HC^N^N=6-(4-苯基)-2,2′-联吡啶)连接到高分子P4VP(聚4-乙烯基吡啶)侧链上,制备了聚4-乙烯基吡啶铂(Ⅱ)配合物[(P4VP)Pt(C^N^N)]Cl。此高分子配合物旋涂膜对醇蒸气具有高度的识别响应能力:膜的荧光强...将小分子金属配合物[Pt(C^N^N)Cl](HC^N^N=6-(4-苯基)-2,2′-联吡啶)连接到高分子P4VP(聚4-乙烯基吡啶)侧链上,制备了聚4-乙烯基吡啶铂(Ⅱ)配合物[(P4VP)Pt(C^N^N)]Cl。此高分子配合物旋涂膜对醇蒸气具有高度的识别响应能力:膜的荧光强度在醇蒸气中迅速猝灭。而在氮气流中,荧光又能够重新开启。整个过程可逆、迅速。膜对不同醇蒸气的敏感能力差别顺序为:甲醇>乙醇>异丙醇。并且荧光强度变化和醇蒸气浓度在一定范围内,具有好的线性关系。此外膜对以上醇蒸气的监测LOD(limit of detection)分别是9.5、16.1和11 ppm。展开更多
Pt heterostructures can have distinctly different physical and chemical properties to their single-phase components. Herein,a smart approach was developed for the large-scale production of graphitic C3N4–Pt(gC 3N4–P...Pt heterostructures can have distinctly different physical and chemical properties to their single-phase components. Herein,a smart approach was developed for the large-scale production of graphitic C3N4–Pt(gC 3N4–Pt) heterostructures on three-dimensional(3D) graphene sheet networks for highly efficient methanol oxidation. Because the gC 3N4–Pt heterostructures on the conductive 3D graphene network support provide the methanol molecules good accessibility to the active sites,the obtained catalyst exhibits excellent electrocatalytic performance,including high catalytic activity,unusual CO tolerance,and good stability,and is superior to commercial Pt/C and Pt/graphene catalysts for methanol oxidation.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51871161 and 52071233)。
文摘Epitaxial Mn_(4)N films with different thicknesses were fabricated by facing-target reactive sputtering and their anomalous Hall effect(AHE)is investigated systematically.The Hall resistivity shows a reversed magnetic hysteresis loop with the magnetic field.The magnitude of the anomalous Hall resistivity sharply decreases with decreasing temperature from300 K to 150 K.The AHE scaling law in Mn_(4)N films is influenced by the temperature-dependent magnetization,carrier concentration and interfacial scattering.Different scaling laws are used to distinguish the various contributions of AHE mechanisms.The scaling exponentγ>2 for the conventional scaling in Mn_(4)N films could be attributed to the residual resistivityρ_(xx0).The longitudinal conductivityσ_(xx)falls into the dirty regime.The scaling ofρ_(AH)=αρ_(xx0)+bρ_(xx)~nis used to separate out the temperature-independentρ_(xx0)from extrinsic contribution.Moreover,the relationship betweenρ_(AH)and pxx is fitted by the proper scaling to clarify the contributions from extrinsic and intrinsic mechanisms of AHE,which demonstrates that the dominant mechanism of AHE in the Mn4 N films can be ascribed to the competition between skew scattering,side jump and the intrinsic mechanisms.
基金financially supported by the National Natural Science Foundation of China(No.52071233)。
文摘The magnetic and electronic transport properties manipulated by spin-orbit torque have been devoted much attention as they show a great promise for future spintronic devices.Here,the spin dependent transport properties of the facing-target sputtered Pt/Mn_(4)N bilayers on MgO(001)substrates have been investigated systematically.The Hall resistivity of Pt/Mn_(4)N bilayers is strongly dependent on temperature,applied current intensity,Mn_(4)N and Pt layer thicknesses.The temperature-dependent sign reversal of anomalous Hall resistivity appears in Pt/Mn_(4)N bilayers,which is dominated by the competition between the magnetic proximity and spin Hall effects.Besides,the magnitude of anomalous Hall resistivity can be manipulated by applied current density.The critical and saturation currents are related to Mn_(4)N and Pt layer thicknesses.Furthermore,a Dzyaloshinskii-Moriya interaction coefficient(D)of 5.63 mJ·m^(-2)is calculated in Pt/Mn_(4)N/MgO systems.The details of the anomalous Hall effects in Pt/Mn_(4)N bilayers are helpful to understand the interfacial effects between heavy metals and ferrimagnets.
基金financially supported by the National Natural Science Foundation of China(Grant No.22172144).
文摘This study aimed to prepare and apply a novel Pt/CdMoO_(4) composite photocatalyst for photocatalytic N2 fixation and tetracycline degradation. The Pt/CdMoO_(4) composite was subjected to comprehensive investigation on the morphology, structure, optical properties, and photoelectric chemical properties. The results demonstrate the dispersion of Pt nanoparticles on the CdMoO_(4) surface. Close contact between CdMoO_(4) and Pt was observed, resulting in the formation of a heterojunction structure at their contact region. Density functional theory calculation and Mott-Schottky analysis revealed that Pt possesses a higher work function value than CdMoO_(4), resulting in electron drift from CdMoO_(4) to Pt and the formation of a Schottky barrier. The presence of this barrier increases the separation efficiency of electron-hole pairs, thereby improving the performance of the Pt/CdMoO_(4) composite in photocatalysis. When exposed to simulated sunlight, the optimal Pt/CdMoO_(4) catalyst displayed a photocatalytic nitrogen fixation rate of 443.7 μmol·L‒^(1)·g‒^(1)·h‒^(1), which is 3.2 times higher than that of pure CdMoO_(4). In addition, the composite also exhibited excellent performance in tetracycline degradation, with hole and superoxide species identified as the primary reactive species. These findings offer practical insights into designing and synthesizing efficient photocatalysts for photocatalytic nitrogen fixation and antibiotics removal.
文摘将小分子金属配合物[Pt(C^N^N)Cl](HC^N^N=6-(4-苯基)-2,2′-联吡啶)连接到高分子P4VP(聚4-乙烯基吡啶)侧链上,制备了聚4-乙烯基吡啶铂(Ⅱ)配合物[(P4VP)Pt(C^N^N)]Cl。此高分子配合物旋涂膜对醇蒸气具有高度的识别响应能力:膜的荧光强度在醇蒸气中迅速猝灭。而在氮气流中,荧光又能够重新开启。整个过程可逆、迅速。膜对不同醇蒸气的敏感能力差别顺序为:甲醇>乙醇>异丙醇。并且荧光强度变化和醇蒸气浓度在一定范围内,具有好的线性关系。此外膜对以上醇蒸气的监测LOD(limit of detection)分别是9.5、16.1和11 ppm。
基金supported by the Ministry of Science and Technology of China (2011CB013000)the National Natural Science Foundation of China (21325415,21174019 and 51161120361)+2 种基金Beijing Natural Science Foundation(2152028)the Fok Ying Tong Education Foundation (131043)the 111 Project (807012)
文摘Pt heterostructures can have distinctly different physical and chemical properties to their single-phase components. Herein,a smart approach was developed for the large-scale production of graphitic C3N4–Pt(gC 3N4–Pt) heterostructures on three-dimensional(3D) graphene sheet networks for highly efficient methanol oxidation. Because the gC 3N4–Pt heterostructures on the conductive 3D graphene network support provide the methanol molecules good accessibility to the active sites,the obtained catalyst exhibits excellent electrocatalytic performance,including high catalytic activity,unusual CO tolerance,and good stability,and is superior to commercial Pt/C and Pt/graphene catalysts for methanol oxidation.
