Isolating Contiguous Ir Atoms and Forming Ir-W Intermetallics with Negatively Charged Ir for Efficient NO Reduction by CO

作者：Ji, Yongjun^*; Liu, Shaomian; Zhu, Hongdan; Xu, Wenqing^*; Jiang, Ruihuan; Zhang, Yu; Yu, Jian; Chen, Wenxing; Jia, Lihua; Jiang, Jingang^*; Zhu, Tingyu; Zhong, Ziyi; Wang, Dingsheng; Xu, Guangwen; Su, Fabing^*

来源：Advanced Materials, 2022, 34(49).

DOI：10.1002/adma.202205703

• CO plus NO
• intermetallic compounds
• Ir single atoms
• O
• (2) resistance
• SO

The lack of efficient catalysts with a wide working temperature window and vital O-2 and SO2 resistance for selective catalytic reduction of NO by CO (CO-SCR) largely hinders its implementation. Here, a novel Ir-based catalyst with only 1 wt% Ir loading is reported for efficient CO-SCR. In this catalyst, contiguous Ir atoms are isolated into single atoms, and Ir-W intermetallic nanoparticles are formed, which are supported on ordered mesoporous SiO2 (KIT-6). Notably, this catalyst enables complete NO conversion to N-2 at 250 degrees C in the presence of 1% O-2 and has a wide temperature window (250-400 degrees C), outperforming the comparison samples with Ir isolated-single-atomic-sites and Ir nanoparticles, respectively. Also, it possesses a high SO2 tolerance. Both experimental results and theoretical calculations reveal that single Ir atoms are negatively charged, dramatically enhancing the NO dissociation, while the Ir-W intermetallic nanoparticles accelerate the reduction of the N2O and NO2 intermediates by CO.

• 单位
  中国科学院; 北京理工大学; 清华大学; 南开大学