In an electrochemical reactor (R) for producing oxygen and hydrogen by means of electrolysis of an electrolyte (16), wherein the electrochemical reactor (R) comprises a first electrode set (S) and wherein the first electrode set (S) comprises a first electrode (7) and a second electrode (8), the first electrode (7) comprises a multitude of pores, the second electrode (8) comprises a multitude of pores, and the first electrode (7) is arranged inside the second electrode (8), such that an electrolyte channel (15) is formed between the first electrode (7) and the second electrode (8).