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

Abstract

Abstract The lack of efficient catalysts with a wide working temperature window and vital O 2 and SO 2 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 SiO 2 (KIT‐6). Notably, this catalyst enables complete NO conversion to N 2 at 250 °C in the presence of 1% O 2 and has a wide temperature window (250–400 °C), outperforming the comparison samples with Ir isolated‐single‐atomic‐sites and Ir nanoparticles, respectively. Also, it possesses a high SO 2 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 N 2 O and NO 2 intermediates by CO.