Chrysanthemum flower like silica with highly dispersed Cu nanoparticles as a high-performance NO<inf>2</inf> adsorbent

Abstract

Atmospheric NO2 removal is urgent and necessary due to its negative effects on the eco-system. Here we developed the chrysanthemum flower-like silica (KCC-1) loaded with highly dispersed copper nanoparticles for efficient NO2 removal under ambient conditions. We carefully studied the NO2 removal performance of Cu-KCC-1 materials with different copper loadings (0, 5, 10, and 15 wt%) and demonstrated the Cu0 nanoparticles (10 wt%) boosted the NO2 removal capacity of KCC-1 by up to 51 times. KCC-1 loaded with 10 wt% of copper was verified to be the best-performing adsorbents, featuring an efficient NO2 removal capacity of 3.63 mmol/g and a moderate NO release (11.3%), which was primarily attributed to the presence of Cu0 nanoparticles. The mechanistic study unveiled that the loaded Cu0 particles served as active adsorption sites for NO2 molecules and reduced the NO2 dissociation by covering the sites primarily responsible for NO2 dissociation (i.e., oxygen vacancies). This work affords a promising adsorbent for NO2 abatement under ambient conditions. The new knowledge established in developing adsorbents for NO2 would promote future research in this emerging and niche area of air pollution control.