Hierarchical Assembly of Multifunctional Oxide-based Composite Nanostructures for Energy and Environmental Applications

Abstract

Composite nanoarchitectures represent a class of nanostructured entities that integrates various dissimilar nanoscale building blocks including nanoparticles, nanowires, and nanofilms toward realizing multifunctional characteristics. A broad array of composite nanoarchitectures can be designed and fabricated, involving generic materials such as metal, ceramics, and polymers in nanoscale form. In this review, we will highlight the latest progress on composite nanostructures in our research group, particularly on various metal oxides including binary semiconductors, ABO3-type perovskites, A2BO4 spinels and quaternary dielectric hydroxyl metal oxides (AB(OH)6) with diverse application potential. Through a generic template strategy in conjunction with various synthetic approaches— such as hydrothermal decomposition, colloidal deposition, physical sputtering, thermal decomposition and thermal oxidation, semiconductor oxide alloy nanowires, metal oxide/perovskite (spinel) composite nanowires, stannate based nanocompostes, as well as semiconductor heterojunction—arrays and networks have been self-assembled in large scale and are being developed as promising classes of composite nanoarchitectures, which may open a new array of advanced nanotechnologies in solid state lighting, solar absorption, photocatalysis and battery, auto-emission control, and chemical sensing.

Structural study of holmium zirconate nanoparticles obtained through carbon neutral sol-gel process

“…[32] . The main advantage of HRTEM is to allow examination of crystal phases in an overlapping nanopowder sample [33] .…”

Nanowire Array Structures for Photocatalytic Energy Conversion and Utilization: A Review of Design Concepts, Assembly and Integration, and Function Enabling

“…Energy Mater. [175] Copyright 2012, the authors. a) Catalytic-induced electrokinetics for autonomous Ag particle movement in bulk Si during the Ag-assisted etching process; b) Si NW arrays obtained from Ag-assisted etching of different types of Si wafers; and c) one of the hierarchical assembly and integration strategies of composite NW array structures developed by Gao's group.…”

“…[188,189] By adjusting the rotation rates of substrates and the trajectory of the incident vapor flux relative to the substrate surface during deposition, a wide range of architectures could be obtained, including tilted columns, zigzag columns, helical columns, and vertical columns. [175] A broad array of promising new classes of composite nanoarchitectures involving generic materials such as metal, ceramics, and polymers can be designed and fabricated, demonstrating diverse application potential. [190] This technique, referred as reactive ballistic deposition (RBD), has successfully demonstrated to prepare a variety of NW/NR structures such α-Fe 2 O 3 and doped α-Fe 2 O 3 , [75,105] TiC, [191] Ge, [192] Si, [193] and Ta 2 O 5 .…”

Synthesis, characterization, and comparative gas sensing properties of tin dioxide nanoflowers and porous nanospheres

“…These structures show well-aligned porous structures without scarifying high surface area, whereas the non-agglomerated form of oxide nanoparticles is extremely difficult to accomplish [14,15]. Among various nanostructured sensor architectures, hierarchical SnO 2 nanostructures such as nanospheres and nanoflowers are very promising gas sensor materials due to their high surface area and well-aligned porous structures with a less agglomerated configuration.…”