Aqueous synthesis and characterization of Hematite Nanorod-based arrays for water splitting and gas sensing applications
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Date
2015
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University of Zululand
Abstract
Hematite, a-Fe2O3, is one of the most stable oxides, with a band gap that ranges between 1.9 and 2.2 eV, and hence a prominent candidate for water splitting applications in sea water conditions. For such an application, the a-Fe2O3 particles should exhibit several singular characteristics: (i) their size should be within the nano-scale regime, (ii) their shape has to
present a significant anisotropy during their growth and can be easily oriented, (iii) should be doped effortlessly. Consequentially, spatially oriented and doped a-Fe2O3 nanorods would allow an effective light trapping/harvesting combined to an efficient and a longer mean free path of the photo-induced charge carriers and hence a faster charge diffusion with a minimized excitonic recombination. The so called Vayssieres' methodology i.e. the aqueous chemical growth (ACG) process has been used in this research work as it is the ideal path to design and engineer the desired Ruthenium doped and spatially oriented a-Fe2O3 nano-rods. The thesis reports on a
comprehensive set of synthesis and characterizations in view of optimizing the water
splitting properties of such Ru doped and undoped a-Fe2O3 photoanodes. In addition, gas sensing potentialities of these Ru doped and undoped a-Fe2O3 have been investigated.
Description
A thesis submitted to the Faculty of Science and Agriculture in fulfilment of the requirements for the Degree of Doctor of Philosophy in Physics in the Department of Physics and Engineering at the University of Zululand, South Africa, 2013.
Keywords
hematite --ACG --nanorods --growth mechanism --water splitting --optical and structural properties --effects of pH --doping --hydrogen sensing