Some aalims (scholars) say: "Rahman" is a name ("Esm") not attribute, just for god. But "Rahim" is an attribute which used for passenger "Mohammad (ص)" in surah "tauba".
Two reasons are explained:

1. We can replace "Allah" instead of "Rahman" everywhere in Quran.
2. "Rahim" used just in kindness of him, but "Rahman" used everywhere.

From here.

Some aalims (scholars) say: "Rahman" is a name ("Esm") not attribute, just for god. But "Rahim" is an attribute which used for passenger "Mohammad (ص)" in surah "tauba".
Two reasons are explained:

1. We can replace "Allah" instead of "Rahman" everywhere in the Quran.
2. "Rahim" used just in kindness of him, but "Rahman" used everywhere.

From here.

Some aalims say: "Rahman" is a name("Esm") not attribute, just for god. But "Rahim" is an attribute which used for passenger "Mohammad(ص)" in surah "tauba".
Two reasons are explained:

1. We can replace "Allah" instead of "Rahman" everywhere in Quran.
2. "Rahim" used just in kindness of him, but "Rahman" used everywhere.

From here.

Some aalims (scholars) say: "Rahman" is a name  ("Esm") not attribute, just for god. But "Rahim" is an attribute which used for passenger "Mohammad  (ص)" in surah "tauba".
Two reasons are explained:

1. We can replace "Allah" instead of "Rahman" everywhere in Quran.
2. "Rahim" used just in kindness of him, but "Rahman" used everywhere.

From here.