Will putting a diesel drop in the back of a pellet for an air rifle create an explosion causing the pellet to travel faster?

Adding any kind of "propellent" into the compression chamber is bad for the gun,

it'll burn the piston seal after a while causing loss in power.

Kinda ironic isn't it?

If you want to get more power, get the gun tuned by a pro air gun tuner, or, buy a gun with more power.