I doubt that your DIY C02 will build enough pressure to go through a diffusor disk. Better try a bubble ladder or diffuse through a powerhead.
Fill a 2L bottle 1/2 full of lukewarm water. Add 1 to 1 1/2 cups white sugar. Shake until dissolved. Fill water to 3/4 full with lukewarm water. Water temps over 70 will kill yeast . Add 1/2 to 3/4 teaspoon yeast. Shake again.
You want it to be a slow, steady reaction. Too much yeast or sugar will result in increased c02 production but reduced duration.