Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Calcium-Decorated Carbon Nanotubes for High-Capacity Hydrogen Storage   Using first-principles calculations, we perform a search for high-capacity
hydrogen storage media based on individually dispersed calcium atoms on doped
or defective carbon nanotubes. We find that up to six H2 molecules can bind to
a Ca atom each with a desirable binding energy of ~0.2 eV/H2. The hybridization
of the empty Ca 3d states with the H2 sigma states contributes to the H2
binding, and Ca clustering is suppressed by preferential binding of Ca atoms to
doped boron and defect sites dispersed on carbon nanotubes. We also show that
individual Ca-decorated B-doped CNTs with a concentration of ~6 at. % B doping
can reach the gravimetric capacity of ~5 wt % hydrogen.

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The categories of this paper are: chem-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: plasm-ph
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
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The categories of this paper are: stat
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: astro-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
0
The categories of this paper are: hep-ph