Studies of electron energy loss spectroscopy and selected area electron diffraction ͑SAED͒ were systematically performed on 15 and 25 at. % lanthanide ͑Ln͒-doped ceria samples ͑Ln= Sm, Gd, Dy, and Yb͒, through which the local ordering of oxygen vacancies that develops with increase in doping level was confirmed in the sequence of ͑Gd, Sm͒ Ͼ DyϾ Yb. Furthermore, a monotone correlation between the development of the ordering and the degradation of ionic conductivity with increasing the doping concentration from 15 to 25 at. % was observed. Based on the analysis of SAED patterns, a structural model for the ordering of oxygen vacancies has been constructed, in which the arrangement of oxygen vacancies is similar to that in C-type Ln 2 O 3 oxides and the 1 2 ͗110͘ pairs of the vacancies are preferred. Then, the factors that can influence the formation of the ordering are discussed.

Buckling-driven assembly of 3D mesostructures from releasable multilayers offers versatile design options for unique applications.

25 at. % Rare-earth (RE)-doped ceria samples (RE=Sm, Dy, Y, and Yb) were examined using transmission electron microscopy and electron energy loss spectroscopy, from which the oxygen vacancy ordering in nanosized domains was confirmed. The relationships of the dopant type, oxygen vacancy ordering, and ionic conductivity of doped ceria were established. It is found that the ordering of oxygen vacancies depends strongly on the dopant type, and the development of nanosized domains with a higher degree of ordering can lead to a more dramatic decrease of ionic conductivity in doped ceria.

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To understand the ceria promotion effect of Pt-CeO(2)/C catalysts on methanol oxidation, microstructural and metal-oxide interactions of Pt-CeO(2)/C catalysts with an atomic ratio of Pt/Ce between 0.14 and 1.4 were systematically examined using high-resolution transmission electron microscopy and electron energy loss spectroscopy (EELS). With an increasing Pt content in the catalysts, Pt particles gradually invaded into the ceria supports and decoration on Pt particles was observed. Simultaneously, the morphology of the supports was dramatically modified with nanocrystalline and amorphous ceria formed between and/or around the Pt particles. It reveals that the Pt-ceria interaction could take place in the catalysts and the influence of the interaction was enhanced with an increasing Pt/Ce ratio. The EELS study demonstrated that the strong Pt-ceria interaction was related to the redox reaction between Pt and ceria. Experimental results also suggested that the strong interaction between Pt and ceria could contribute to the promotion effect of ceria on the oxidation of methanol.

Power supply for medical implantable devices (i.e. pacemaker) always challenges not only the surgery but also the battery technology. Here, we report a strategy for energy harvesting from the heart motion by using ultra-flexible piezoelectric device based on lead zirconate titanate (PZT) ceramics that has most excellent piezoelectricity in commercial materials, without any burden or damage to hearts. Experimental swine are selected for in vivo test with different settings, i.e. opened chest, close chest and awake from anesthesia, to simulate the scenario of application in body due to their hearts similar to human. The results show the peak-to-peak voltage can reach as high as 3 V when the ultra-flexible piezoelectric device is fixed from left ventricular apex to right ventricle. This demonstrates the possibility and feasibility of fully using the biomechanical energy from heart motion in human body for sustainably driving implantable devices.

Reluctant oxygen-reduction-reaction (ORR) activity has been a long-standing challenge limiting cell performance for solid oxide fuel cells (SOFCs) in both centralized and distributed power applications. We report here that this challenge has been tackled with coloading of (La,Sr)MnO3 (LSM) and Y2O3 stabilized zirconia (YSZ) nanoparticles within a porous YSZ framework. This design dramatically improves ORR activity, enhances fuel cell output (200-300% power improvement), and enables superior stability (no observed degradation within 500 h of operation) from 600 to 800 °C. The improved performance is attributed to the intimate contacts between nanoparticulate YSZ and LSM particles in the three-phase boundaries in the cathode.