Ground-level ozone pollution poses significant risks to ecosystems and human health and requires effective control measures. This study focused on the monolithic ozone degradation catalyst based on powdered α-MnO₂ and comprehensively investigated its catalytic performance, moisture resistance, and stability. The monolithic catalyst achieved the optimal catalytic activity with an ozone conversion rate of 99% after being calcined at 400 °C for 3 hours. The detailed characterization of the catalyst properties at pH = 1, 4, and 7 revealed the adverse effects of residual acid ions on the catalyst activity. The catalyst at pH = 7 had more oxygen vacancies, which was related to the reduction of sulfate ion residues and the exposure of more active sites during the washing process. At pH = 7 and a space velocity of 900 000 h⁻¹, the conversion rates of α-MnO₂ to 18 ppm ozone reached 100% and 95% within 3 hours under 90% relative humidity and dry conditions, respectively. In addition, the monolithic catalyst exhibited significant moisture resistance and performed well in continuous alternating humidity cycle tests and sustained high humidity. It still maintained 90% ozone decomposition efficiency after 3 hours of testing under high humidity conditions. Meanwhile, the α-MnO₂ monolithic catalyst showed excellent stability, with an ozone conversion rate exceeding 99% during the 50 – hour test period. These findings highlight the great potential of the α-MnO₂ monolithic catalyst in ozone removal applications.

中文翻译：

---

在高湿度条件下具有高效臭氧催化分解能力的 α-MnO2 催化剂


地面臭氧污染对生态系统和人类健康构成重大风险，需要采取有效的控制措施。本研究以基于粉末状 α-MnO₂ 的整体臭氧降解催化剂为重点，并全面研究了其催化性能、耐湿性和稳定性。该整体催化剂在 400 °C 下煅烧 3 小时后达到最佳催化活性，臭氧转化率为 99%。在 pH = 1、4 和 7 时催化剂性能的详细表征揭示了残余酸离子对催化剂活性的不利影响。pH = 7 时的催化剂具有更多的氧空位，这与洗涤过程中硫酸根离子残留物的减少和更多活性位点的暴露有关。在 pH = 7 和 900 000 ^h-1 空速下，在 90% 相对湿度和干燥条件下，α-MnO₂ 到 18 ppm 臭氧的转化率在 3 小时内分别达到 100% 和 95%。此外，该整体催化剂表现出显著的防潮性，在连续交变湿度循环测试和持续高湿度测试中表现良好。在高湿度条件下测试 3 小时后，它仍然保持了 90% 的臭氧分解效率。同时，α-MnO₂ 整体催化剂表现出优异的稳定性，在 50 小时的测试期间臭氧转化率超过 99%。这些发现凸显了 α-MnO₂ 整体催化剂在臭氧去除应用中的巨大潜力。