Construction of MnOx with abundant surface hydroxyl groups for efficient ozone decomposition

Abstract

Designing and constructing stable and high-performance catalysts for room-temperature ozone decomposition under humid conditions remains a significant challenge. Herein, we report manganese oxide (MnO_x) rich in surface hydroxyl groups (-OH), synthesized through a facile three-step process combining solid-state grinding, heat treatment, and hydrothermal activation using potassium permanganate and ascorbic acid as precursors. The as-prepared catalyst (MnO_x-A) demonstrated remarkable stability with 100 % ozone conversion maintained for 240 min under ≤ 50 % relative humidity (RH). Notably, it achieved 90 % ozone conversion after 240 min even under 90 % RH, surpassing its performance (79 % conversion) at 70 % RH. Through comprehensive characterization and density functional theory calculations, we revealed that the abundant surface -OH groups effectively mitigate the water-induced deactivation of MnO_x during room-temperature catalytic ozone decomposition under humid conditions. Furthermore, we established a correlation between the catalytic activity of -OH groups and the manganese valence state. These findings provide valuable insights for the rational design of highly efficient and stable catalysts for practical ozone elimination applications.