To directly denitrate high-temperature flue gas, excellent thermal stability, along with good adsorption capacity and recyclability, is the key factor for practical application. Hence, polyaniline (PANI) seems a promising candidate for its well-known high adsorption capacity. With the aim to further improve PANT, in this study, aniline was in situ polymerized with different clays to result in clay/PANI composites. The results demonstrated the attapulgite (ATP)/PANI composite (mass ratio of 2:1) had an adsorption capacity of 4.90 mmol.g(-1) 59.1% higher than that of pure PANI. Good recyclability (99.0% for 10 cycles) and a high decomposition temperature (over 500 degrees C) were also observed for the ATP/PANI composite. In addition, as a byproduct, the washed-away NH4 NO3 that was generated from the adsorbed NO2 is an agricultural fertilizer of wide application. Overall, this study shows a good prospect for direct denitrition of fresh flue gas over the clay/PANI composite adsorbents.