Volkner has the following in Diamond and Pearl:
Raichu
Octillery
Ambipom
Luxray
And he has these in Platinum:
Jolteon
Raichu
Luxray
Electivire
Volkner (last gym leader) has a Raichu, Octillery, Ambipom and Luxray. You should use Ground Type Pokémon for Raichu and Luxray but you should use a fighting type for Ambipom and a grass type for Octillery however watch out cause his Octillery knows Bullet Seed.
His name is Volkner and he is the gym leader of Sunyshore. To get to Sunyshore travel to the right of Pastoria and lake Valor.
gym leader volkner in sunyshore city
Gym Leader Jasmine of Johto will give it to you. She is located at the shore in the northeast part of Sunyshore City.
In sunyshore city talk to the girl on the beach she will tell you to beat the gym leader, do it, then talk to her again and she will give it to you! Easy as that!
Start at the entrance to the town: Go up the stairs by the entrance. Keep on going right. Go on the first path to the north. Now go left. Good luck beating the gym leader!!!
the gym leader volkner uses electric Pokemon
His name is Volkner and he is the gym leader of Sunyshore. To get to Sunyshore travel to the right of Pastoria and lake Valor.
in sunyshore city
The Sunyshore City Gym Leader can be found in the city's Lighthouse.
you must talk to him in the lighthouse, in sunyshore then you can go in
The Johto Gym Leader Jasmine from Olivine City is in Sunyshore City.
from that gym leader on the beach of sunyshore city (must have beaten the 8th gym)
you need to cacth dialga first
use ground type
you go to Sunyshore City and defeat the las gym leader
the 8th gym leader in sunyshore city. to unlock it cath palkia or dialga.
beat all gyms or cheat with ar ds