Abstract: An electrochemical double-cell plate for exhaust emissions control is used to purify a lean-burn exhaust and comprises a substrate made of a metal or an alloy and having a reducing capability; a solid-oxide layer; a side layer; and a cathode layer. The solid-oxide layer and the side layer join to seal the substrate and respectively have a first dense structure and a second dense structure. The cathode layer completely covers the solid-oxide layer, made of a porous material and having an oxidizing environment. The oxidizing environment and the reducing capability generate an electromotive force between the substrate and the cathode layer. The electromotive force promotes sulfur oxides and nitrogen oxides of the lean-burn exhaust to decompose into sulfur vapor, oxygen and nitrogen. An electrochemical apparatus using the same for exhaust emissions control is also disclosed.