Encapsulate α-MnO2 nanofiber within graphene layer to tune surface electronic structure for efficient ozone decomposition

Major challenges encountered when developing manganese-based materials for ozone decomposition are related to the low stability and water inactivation. To solve these problems, a hierarchical structure consisted of graphene encapsulating alpha -MnO2 nanofiber was developed. The optimized catalyst exhibited a stable ozone conversion efficiency of 80% and excellent stability over 100h under a relative humidity (RH) of 20%. Even though the RH increased to 50%, the ozone conversion also reached 70%, well beyond the performance of alpha -MnO2 nanofiber. Here, surface graphite carbon was activated by capturing the electron from inner unsaturated Mn atoms. The excellent stability originated from the moderate local work function, which compromised the reaction barriers in the adsorption of ozone molecule and the desorption of the intermediate oxygen species. The hydrophobic graphene shells hindered the chemisorption of water vapour, consequently enhanced its water resistance. This work offered insights for catalyst design and would promote the practical application of manganese-based catalysts in ozone decomposition. Ozone is a major air pollutant, but its elimination is challenging. Here the authors encapsulate defective alpha -MnO2 nanofiber within ultrathin graphene shells to construct a hierarchical MnO2@graphene catalyst for ozone decomposition that possesses high activity and stability under humid conditions.

Automated summary

This study has developed a hierarchical MnO2@graphene catalyst for ozone decomposition, which encapsulates defective alpha -MnO2 nanofiber within ultrathin graphene shells. The catalyst shows high activity and stability under humid conditions.