Zheng Li,Yuling Su,Yuying Zuo,Gaoshang Gong,Yaran Duan,Minghao Wang,Maocai Wei,Yongqiang Wang
In this paper, the crystal structure, vacancies, magnetoelectric properties and magneto-thermal properties of Gd 1- x Dy x CrO 3 (0 ≤ x ≤ 0.5) samples were reported. In crystal structure analysis, after doping Dy 3+ , the lattice constant and the grain size of the sample decreases. The results of positron annihilation lifetime study indicates that the overall electron density near defect increases and that appeared as a gradual decreasing trend of τ 2 with Dy 3+ concentration. The ferromagnetism of the sample gradually decreased after doping, and the T N (Cr) of the sample decreased systematically with increasing concentration of Dy 3+ . Moreover, the introduction of Dy 3+ inhibited the magneto-electric coupling and weakened the magneto-thermal properties of the samples. This result reveals the effect of Dy 3+ doping on the structure, magnetic properties, magnetothermal and dielectric properties of GdCrO 3 .
Jingwei Li,Zhengyi Huang,Cong Wang,Lei Tian,Xiaoqing Yang,Rongfu Zhou,Mohamed Nawfal Ghazzal,Zhao-Qing Liu
Refining carrier transfer in bandgap-broken heterojunctions, which consist of two semiconductors with broken bandgaps, is crucial yet highly challenging for photocatalysis. Herein, we incorporated amorphous carbons (AC) into the bandgap-broken V 2 O 5 /GdCrO 3 heterojunctions, inducing a linkage effect to facilitate photoexcited carrier transfer. The created V-O-C and Cr-O-C bonds in V 2 O 5 -AC-GdCrO 3 interfaces show almost identical orbital energies to overcome the broken-gap energy barriers at interfaces. The holes at GdCrO 3 ’s valence band and electrons at V 2 O 5 ’s conduction band tent to migrating toward the carbon ring of amorphous carbon via Cr-O-C and V-O-C bonds, thereby enhancing carrier separation of bandgap-broken V 2 O 5 /AC/GdCrO 3 heterojunction. By controlling the relative amount of metal-O-C bonds in the interface, the modulation of charge transfer kinetics was also achieved on V 2 O 5 /AC/GdCrO 3 , resulting in ∼7 times higher of H 2 generation than V 2 O 5 /GdCrO 3 . The concept could be expanded to the other carbon allotropes, including graphene, carbon nanotube, and graphdiyne conjugated structures, demonstrating a universal strategy in reaching optimal charge transfer of broken-bandgap heterojunctions for photocatalytic H 2 production.
This work reports a novel strategy to activate type III heterojunction through introducing defect sites at the interfaces and making use of the defect band as the bridge for storage, secondary excitation, and interband transfer of the photothermal induced charges for constructing two-component Type B heterojunction photothermocatalyst. Type III heterojunction WO 3−x /GdCrO 3 is activated by defect-band state W 5/4+ at WO 3−x interface under photothermal conditions, achieving efficient charge separation, high redox potential, and full visible light absorption. The as-bridged (or Type B) heterojunction WO 3−x -R/GdCrO 3 as non-noble metal catalyst demonstrates excellent photothermocatalytic performance in toluene degradation with a reaction rate five times higher than that of WO 3−x /GdCrO 3 with less interfacial defect sites as well as in CO 2 reduction with high CO and CH 4 yielding rates of 49.6 μmol g −1 h −1 and 18.5 μmol g −1 h −1 in gas-solid reaction system without sacrifice agent, evidently better than those reported in the literature.
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