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.

中文翻译：

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调节具有超强活性的超薄δ-MnO2纳米片中的氧空位，以分解气态臭氧

地面臭氧污染是全球范围内的环境问题，对人类健康尤其是老年人，儿童和敏感人群有害。开发用于在实际条件下彻底分解臭氧的高性能催化剂是一个艰巨的挑战，因为氧气的空位，即反应位点，往往被水分子或中间的过氧化物所占据。在本文中，超薄δ-的MnO ₂纳米片富含氧空位与铵离子的调制（NH被简单地制造₄ ⁺）。此外，调节氧空位通过NH ₄ ⁺离子在超薄δ-MnO的成功实施_2个纳米片。表面吸附NH₄ ⁺离子促进了臭氧的吸收，并减少了水分子的竞争性吸附。尤其是，如原位拉曼光谱和DFT计算所证明的那样，中间体的解吸通过NH ₄ ⁺离子加速。所合成的催化剂在潮湿条件下对气态臭氧分解表现出相当出色的活性和稳定性，在相对湿度为50％的情况下，在36 h内可保持100 ppm臭氧的几乎100％的转化率，在50％的相对湿度下可保持600 L g ^-1 h ^-1的空速。 25℃。这项工作提供了一种简便，有效的和可扩展的方法来合成超薄δ-的MnO ₂ 纳米片并调节氧空位，并进一步开发出一种高效，低成本的臭氧去除催化材料。