You can buy a standard glass/ceramic diffuser, most of which will work with DIY CO2. Loads available on Evilbay, just look at the fine print for "not for use with DIY CO2" or somesuch. Buy 2 or 3 (you're still spending $10 or less), because quality is hit or miss, and they're fairly fragile.
The "Atomizer" or "Atomic" type requires somewhere around 30psi to function, which is far higher than you'll be able to create with DIY CO2. Or, more accurately, your hoses will blow off, or out of, something or other long before you get 30 psi.