Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Transparent TiO2 Nanotubes Arrays Directly Grown on Quartz Glass Used in
  Front- and Back-Side Irradiation Configuration for Photocatalytic H2
  Generation   In the present work we explore the front- and back-side performance of a
photocatalytic platform consisting of self-organized TiO2 nanotube layers
formed by complete anodization of Ti metal films evaporated on quartz slides.
The adhesion and light transmission of the tube layers on the quartz surfaces
are optimized by a suitable anodization procedure. After their growth, the
nanotube arrays were converted into crystalline structures and sputter-coated
with co-catalytic Pt nanoparticles. The optically transparent quartz substrates
enable the use of the Pt-decorated tube layers for photocatalytic H2 generation
under either front- or back-side illumination configurations. The nanotube
films on quartz are characterized in view of their physico-chemical properties,
including their light transmission features measured using different light
sources. The results show that the front-side illumination under optimized
factors, i.e., the amount of loaded co-catalyst, yields a maximized
photocatalytic performance in terms of H2 generation.

8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin