Single-crystalline transition metal oxide thin film has been employed to perceive the fundamental functions of electronic structure and charge transfer processes in water splitting processes. However, the surface area enlargement and strain tunability in a single-crystalline transition metal oxide are restricted in conventional epitaxy . In this study, we report the oxygen evolution reaction (OER) enhancement by a stack of multilayer SrRuO 3 featured single-crystallinity, flexibility, and stackability. The controllable stack of multiple cylindrical SrRuO 3 for surface enlargement in a magnitude of order and the emergent electronic structure transition, from t 2g (3↑, 1↓) to t 2g (3↑) e g (1↑), of Ru efficiently enhances the OER performance, the overpotential can be reduced by ~74 % and ~78 % in KOH and HClO 4 respectively at 5 mA/cm 2 . Our study provides an approach for fine manipulation of single-crystalline freestanding oxide morphologically, and an efficient strategy aiming at the extreme enhancement of the electrochemically active surface area and the electronic structure engineering by strain.
Fu Shuai,Tan Yiyu,Sun Xiaofan,Tang Zheng,Jiao Shulin,Cai H. L.,Zhang F. M.,Zhang A. M.,Wu X. S.
Here, equal numbers of La and Mn ions are successfully introduced simultaneously in SrRuO3. With increasing La/Mn doping, all compositions crystallize in Pnma with the lattice constant, together with the RuO 6 octahedral distortion, decreases. Ferromagnetism-to-spin glass magnetic behavior is observed at x ≥ 0.23. A metal–insulator transition (MIT) occurs at lower temperatures, resulting from the disordering of the metal mixture in the lattice. The retraction of the RuO 6 octahedron increases the overlap of the Ru t 2g –O 2p orbitals and broadens the Ru 4d bandwidth, leading to weaker electron–electron interactions, which may decrease the electronic and thermal conductivity.
Effects of Sn doping at Ru site on the structural, magnetic, and transport behavior of polycrystalline SrRu 1− x Sn x O 3 ( x ≤ 0.1) have been investigated here. Substitution of Sn 4+ for Ru 4+ remains the same crystal symmetry with that of Sn-free SrRuO 3 , while induces the Ru(Sn)O 6 octahedral distortions. Samples with the low doping concentration ( x ≤ 0.08) show a metallic behavior at high temperature, while a metal to insulator transition occurs at low temperature. On the other hand, an insulator behavior is detected for sample with x = 0.1, which follows Arrhenius-type process in the temperature range of 80–140 K and Mott's variable range hopping model in the temperature range of 140–300 K. Further, we find that Sn 4+ has a significant effect on the magnetic behavior of Sn doping in SrRuO 3 where ferromagnetic transition temperature and magnetic moment decrease rapidly due to octahedral distortion and site dilution.
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