Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Energy conversion processes with perovskite-type materials   Mixed oxides derived from the perovskite structure by combination of A- and
B-site elements and by partial substitution of oxygen provide an immense
playground of physico-chemical properties. Here, we account for own research
conducted at the Paul Scherrer Institute on perovskite-type oxides and
oxynitrides used in electrochemical, photo(electro)chemical and catalytic
processes aiming at facing energy relevant issues.

2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an