Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spaced TiO$_2$ Nanotube Arrays Allow for High Performance Hierarchical
  Supercapacitor Structure   In this work we describe the synthesis and electrochemical properties of
nitridated hierarchical TiO$_2$ nanotubes as an electrode for supercapacitors.
The hierarchical TiO$_2$ nanostructures are formed by a controlled
layer-by-layer TiO2 nanoparticle decoration on self-organized spaced TiO$_2$
nanotubes. These structures are then annealed in NH$_3$ atmosphere at elevated
temperature to convert the material to a nitride structure -- this drastically
enhances their electron-transport properties. The areal capacitance of
hierarchical structures can be tuned by changing the number of decorated
TiO$_2$ nanoparticle layers. The capacitance enhancement of the hierarchical
structures reaches a maximum when the surface area through nanoparticle
deposition is highest and the conductivity via nitridation is optimized.

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The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-th
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The categories of this paper are: cs
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The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
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The categories of this paper are: astro-ph
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The categories of this paper are: ao-sci