Ji Jiafan, Yan Qianqian, Chen Yi, Zhao Gaosheng, Jia Bin, Xu Li, Cheng Ping
School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China.
Analyst. 2024 Dec 16;150(1):197-206. doi: 10.1039/d4an01095g.
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-MnO 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, the conversion rates of α-MnO 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-MnO 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-MnO monolithic catalyst in ozone removal applications.
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。本研究聚焦于基于粉末状α-MnO₂的整体式臭氧降解催化剂，并全面研究了其催化性能、耐湿性和稳定性。该整体式催化剂在400℃下煅烧3小时后，臭氧转化率达到99%，实现了最佳催化活性。在pH = 1、4和7条件下对催化剂性能进行的详细表征揭示了残留酸离子对催化剂活性的不利影响。pH = 7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的减少以及更多活性位点的暴露有关。在pH = 7、空速为900 000 h⁻¹的条件下，α-MnO₂对18 ppm臭氧的转化率在90%相对湿度和干燥条件下分别在3小时内达到100%和95%。此外，该整体式催化剂表现出显著的耐湿性，在连续交替湿度循环测试和持续高湿度环境中性能良好。在高湿度条件下测试3小时后，其仍保持90%的臭氧分解效率。同时，α-MnO₂整体式催化剂表现出优异的稳定性，在50小时的测试期内臭氧转化率超过99%。这些发现突出了α-MnO₂整体式催化剂在臭氧去除应用中的巨大潜力。
