A processing chamber comprising a reaction vessel having an electro-reaction cell including a virtual electrode unit, an electrode assembly disposed relative to the electro-reaction cell to be in fluid communication with the virtual electrode unit, and an electrode in the electrode assembly. The virtual electrode unit has at least one opening defining at least one virtual electrode in the electro-reaction cell. The electrode assembly can include an electrode compartment and an interface element in the electrode compartment. The interface element can be a filter, a membrane, a basket, and/or another device configured to hold the electrode. The interface element, for example, can be a filter that surrounds a basket in which the electrode is positioned.