To overcome the problems of a conventional electrochemical-catalytic converter which purifies gas, including high fabrication cost and bulky volume.

This electrocatalytic tube for controlling exhaust emissions is used to purify an oxygen-rich combustion exhaust gas. The electrocatalytic tube includes a tubular body, an anode layer, and a cathode layer. The tubular body is constituted of a solid oxide layer. The solid oxide layer includes a sealed chamber, and an inner wall face and an outer wall face of the sealed chamber. The anode layer and the cathode layer are disposed on the inner wall face and the outer wall face. The sealed chamber includes a reducing environment. The oxidizing environment of the oxygen-rich combustion exhaust gas generates electromotive force between the anode layer and the cathode layer, and promotes a catalyst decomposing reaction for purifying nitrogen oxide in the oxygen-rich combustion exhaust gas in the cathode layer. The electrochemical catalyst converter has simple structure and lower fabrication cost than the existing conventional electrochemical-catalytic converter.