An electrochemical NO2 sensor includes a reference electrode, a sensing electrode having a sensing electrode material, and an electrolyte. The electrolyte is disposed between and in ionic communication with the sensing electrode and the reference electrode to form an NO2 sensing cell. The NO2 sensing cell produces an electromotive force when exposed to NO2. The sensing electrode material comprises a compound consisting essentially of Si and oxygen and expressed by ABD. Oxygen is element D, Si is element B, and element A includes one or more elements selected from the group consisting of Mn, Co, and Fe.