No you can't
you cannot catch arceus but you can get it as a MYSTERY GIFT you from trading with DIAMOND/PEARL/PLATINUM.anyway i hope you enjoy your arceus.
You can either get the mystery gift arceus, the mystery gift azure flute, and lastly action replay.
Pokemart or Mystery Gift
Currently you cannot capture Arceus in the wild or by events in Pokemon Diamond and Pearl. (The Azure Flute Mystery Gift event was never released.) You will need to use an Action Replay or trade for it with a friend.
how can i catch arceus
june 30th
you need the azure flute i think you get it from mystery gift then go to a Nintendo event
the Sinjoh Ruins are only accessible with an unhacked, legal Arceus, from a Mystery Gift (not the event). Transfer from Diamond/Pearl/Platinum and bring the Arceus as your only Pokemon to the Ruins of Alph. Cynthia will appear, you will follow her and she brings you to the Sinjoh Ruins. since Arceus has only been given out as a Mystery Gift a few times, it is unlikely you will be able to get there
you get the myster gift in a Nintendo event
you can get him by cheats but without the mystery gift i am not sure i will try to ask gamefreek for an update.
Mystery gift is a place to get the azure flute for arceus,member pass for darkrai and oaks letters for shaymin BY=RAFI Mystery gift is a place to get the azure flute for arceus,member pass for darkrai and oaks letters for shaymin BY=RAFI