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

Abstract

The lack of efficient catalysts with a wide working temperature window and vital O2 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 N2 at 250 °C in the presence of 1% O2 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 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.

Tailoring the Electronic Structure of Single Ag Atoms in Ag/WO3 for Efficient NO Reduction by CO in the Presence of O2

“…In the case of NO adsorption on 0.3Ag/m-WO 3 at 50 °C (Figure S24), the intense band observed at 1375 cm –1 is ascribed to nitrite species (NO 2 – ) . As exhibited in the enlarged view at 1500–2500 cm –1 (Figure a), a relatively strong band appears at 1769 cm –1 , corresponding to the adsorbed NO – species, and two visible bands at about 2250–2360 cm –1 are assignable to N 2 O. − Some small bands at 1595 cm –1 (bidentate nitrate), ,, 1629 cm –1 (NO 2 ), − and 1854 and 1902 cm –1 (gaseous NO) , are also observed. Adding O 2 to the feed enhances the formation of NO 2 and bidentate nitrate, but it has almost no impact on the bands of the adsorbed NO and N 2 O, indicating that the adsorption sites of NO were not blocked.…”

Adjacent atomic cobalt sites anchored on carbon foam as a self-supporting electrode for efficient hydrogen evolution

“…This reveals that the electron state of the Co 1 /Co 2 atom increases and its ability to promote charge transfer is strengthened. 48,49 This electron-rich state may regulate the dorbital structure of the Co atom and then benet the binding with the reaction intermediate. The interaction between the intermediate and the metal atomic site of the catalyst can also be evaluated by the d-band center of the metal atomic site.…”

Recent progress in intermetallic nanocrystals for electrocatalysis: From binary to ternary to high‐entropy intermetallics

“…Third, instead of using 2D sheets as substrates, threedimensional (3D) frameworks can be used to confine the growth of nanoparticles inside the pores, thereby preventing particle aggregation and enabling size control. Mesoporous carbon, 24,75 silica, 70,[76][77][78][79][80] zeolite, 81 and salt matrix 23,71,82,83 have been reported as the 3D frameworks. For example, mesoporous silica (SBA-15) was used as the substrate, onto which Rh and Zn precursors were impregnated.…”