Regulating oxygen vacancies in ultrathin δ-MnO2 nanosheets with superior activity for gaseous ozone decomposition†
*ab
Shaopeng
Rong
c
Abstract
Ground-level ozone pollution is an environmental problem worldwide, and is hazardous to human health, especially the elderly, the children and the sensitive. It is a tough challenge to develop high-performance catalysts for thoroughly decomposing ozone under practical conditions because oxygen vacancies, i.e. reaction sites, tend to be occupied by water molecules or intermediate peroxides. Herein, ultrathin δ-MnO2 nanosheets rich in oxygen vacancies were simply fabricated with the modulation of ammonium ions (NH4+). Furthermore, regulating oxygen vacancies via NH4+ ions was successfully implemented in ultrathin δ-MnO2 nanosheets. The surface adsorbed NH4+ ions facilitated the ozone adsorption and reduced the competitive adsorption of water molecules. In particular, the desorption of intermediates was accelerated by NH4+ ions, as demonstrated by in situ Raman spectroscopy and DFT calculations. The as-synthesized catalyst exhibited rather excellent activity and stability for gaseous ozone decomposition under humid conditions, maintaining almost 100% conversion of 100 ppm ozone within 36 h at 50% relative humidity and a space velocity of 600 L g−1 h−1 at 25 °C. This work provides a facile, effective and scalable method to synthesize ultrathin δ-MnO2 nanosheets and regulate oxygen vacancies and further develops a high-efficiency and low-cost catalytic material for ozone removal.
- This article is part of the themed collection: Nanomaterials in air
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