Metal oxide heterostructures

This chapter presents a critical review on the newly developed procedures for multidimensional electrode nanoarchitecturing for Li- and Na-ion batteries. Starting from nt-Ti02 utilization, first-row transition metal oxide nanocomposites are examined. Metal foams for 2D and 3D battery architectures and graphene-transition metal oxide heterostructures with unusual performance for battery applications are discussed. 

Graphene—Transition Metal Oxide Heterostructures for Battery Applications 383... 

Many of the same ionic surfactants used for the assembly of mesostructured molecular sieve catalysts [1-4] and related bulk phases [5] can be intercalated in a variety of layered host structures [6]. We have recently demonstrated that some of these mesostructure - forming surfactants retain their structure directing properties when intercalated in the galleries of smectite clays. In a manner quite analogous to bulk mesostructure formation, the intercalated surfactants direct the assembly of an open framework metal oxide (silica) structure within the constrained gallery regions of the layered host (7). The resulting porous intercalates are referred to as porous clay heterostructures (PCH). 

Noble metal-metal oxide dumbbell-shaped NPs have been synthesized based on seed-mediated growth. Metal oxides are grown over the pre-synthesized noble metal seeds by the thermal decomposition of the metal carbonyl followed by oxidation in air. They show enhanced catalytic activity towards CO oxidation in comparison with their counterparts [94]. Heterostructured Cu2S-ln2S3 with various shapes and compositions can be obtained by a high-temperature precursor-injection method wherein Cuj is used as the catalyst for the nucleation and growth of In Sj NPs [95]. 

It should be noted that, similarly to conventional metal oxide gas sensors, high porosity of material used for heterostructure forming is one of the main reqnirements for achievement of high sensitivity. 

As mentioned, the solid electrolytes are sintered metal oxides with mobility of ions where the ionic conductivity is influenced by both the microstructure and geometry. The effects of composition, structure, microstructure, and strain on ionic transport at grain boundary provided complementary tools for futiu-e developments in solid electrolyte materials. Among these, a particular attention was given to the impact on ionic transport of defects in various types of structures, dislocations, grain boundaries, and heterostructure interfaces. The design of such structural properties also considered the achievements of the development in nanotechnologies. 

Wang H, Ma D, Huang Y, Zhang X (2012) General and controllable synthesis strategy of metal oxide/Ti02 hierarchical heterostructures with improved lithium-ion battery performance. Nat Sci Rep 2 701... 

CVD = chemical vapor deposition DH = double heterostructure H = homojunction device ITO = indium tin oxide LEDs = light emitting diodes LPE = liquid phase epitaxy MBE = molecular beam epitaxy MOCVD = metal organic chemical vapor deposition PPV = p-phenylenevinyl-ene PEDOT = polyethylene dioxythiophene TFEL = Thin film electroluminescent VPE = vapor phase epitaxy. 

Figure 6.2 Schematic diagram of solar cells with extended junctions and an extremely thin absorber (a) Layer structure for a superstrate n-i-p cell in this configuration a highly structured ra-layer is deposited on a transparent conductive oxide (TCO) contact layer, then a conformal absorber layer is deposited, followed by a transparent p-type transport layer and finally a reflective metal contact (b) Band diagram for the n-i-p heterojunction. The valence-band edges Ey) and conduction band edges Ec) for the absorber and transport layers and the electron and hole quasi-Fermi levels are shown (c) Illustration of reduced transport paths in the absorber layer and extended optical paths due to scattering in the heterostructure (d) Extremely thin absorber cell with a comparably shallow structure and a metal back contact in place of a transparent transport layer.

The explanation of endotactic heterostructures in molecular dispersion for the X-ray anomalies of ammonia iron was proved by H. Topsoe by Mossbauer spectroscopy. The Mossbauer data imply the presence of small amounts of non-metal iron components which are present, however, as large particles of structural promoter oxides. They are located in grain boundaries and at the outer surface of the catalyst. This location also explains the SIMS data on Fe-Al-O fragments which were intended to support the hypothesis of endotactic heterostructures.The EXAFS data ° ° provide clear evidence for the identical average local coordination of iron in ammonia iron and normal iron. 

ZnO, and heterostructure devices. Among the devices, light emitters, microcavities, optically pumped lasers, photodiodes, metal-insulator-semiconductor diodes, field-effect transistors, transparent conducting oxides, and transparent thin-fihn transistors based on ZnO, piezoelectric devices in the form of surface acoustic wave devices, and gas and biosensor followed by solar cells cap the discussion. 

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