In situ synthesis of coral-like ε-MnO₂ by ozone for efficient ozone decomposition across varied humidity environments

MnOx-based materials have attracted significant attention for ozone decomposition due to their excellent catalytic activity. However, improving their stability and water resistance under humid conditions remains a major challenge. In this work, a K⁺-doped ε-MnO₂ catalyst was synthesized in situ using ozone as an oxidant. The resulting catalyst exhibited outstanding ozone decomposition performance under both low temperature (0 °C) and high humidity conditions. Ozone treatment contributed to the formation of a more complete crystal structure and a higher concentration of oxygen vacancies. K⁺ doping further increased the specific surface area (174.1 m²/g), reduced the grain size, and enhanced the catalyst's redox properties and surface reactive oxygen species content. Post-reaction XPS, FTIR, and Raman analyses revealed that no accumulation of O₂^2- species was detected on the surface under these conditions. This absence of peroxide intermediates is believed to contribute to the catalyst's excellent stability and water resistance. This study provides new insights into the design of highly efficient and durable ozone decomposition catalysts for environmental applications.