mixed egg and bicarbonate of soda
Perishable food, including raw eggs, is safe in the fridge for a day. So you can do that. 

The soda can spend its leavening power though, especially if you also have other ingredients mixed in. The cookies will not have the same texture as freshly made, and it is hard to say how much difference there will be and where on the spectrum is your limit for "acceptable quality". So, you can go ahead and make them, but be aware that you are facing a significant probability of failure.