Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Photocatalytic Degradation of Methylene Blue by ZnO/NiFe2O4
  Nanoparticles
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol