Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Yttrium Tantalum Oxynitride Multiphases as Photoanodes for Water
  Oxidation   Perovskite yttrium tantalum oxynitride is theoretically proposed as a
promising semiconductor for solar water splitting because of the predicted
bandgap and energy positions of band edges. In experiment, however, we show
here that depending on processing parameters, yttrium tantalum oxynitrides
exist in multiphases, including the desired perovskite YTaON2, defect fluorite
YTa(O,N,o)4, and N-doped YTaO4. These multiphases have bandgaps ranging between
2.13 and 2.31 eV, all responsive to visible light. The N-doped YTaO4,
perovskite main phase, and fluorite main phase derived from crystalline
fergusonite oxide precursors exhibit interesting photoelectrochemical
performances for water oxidation, while the defect fluorite derived from low
crystallized scheelite-type oxide precursors show negligible activity.
Preliminarily measurements show that loading IrOx cocatalyst on N-doped YTaO4
significantly improves its photoelectrochemical performance encouraging further
studies to optimize this new material for solar fuel production.

29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org