Dye-sensitized solar cells (DSCs) have attracted intense research attention owing to their ease of fabrication,cost-effectiveness and high efficiency in converting solar energy.Owing to the low abundance and high costs of noble platinum electrode,which precludes the large-scale utilizations of DSCs.researchers are facing with the challenge of developing low-cost and earth-abundant altematives.Here,using the first-principles calculations,we studied the catalytic activity of the interstitial nitrogen-doped Sri02 electrode toward iodide reduction reaction,aiming at addressing the N doping effect on altering the electrocatalytic activity of some unreactive metal oxides,and predicting the potentially active conductor counter electrodes.