3D hierarchical structures MnO2/C: A highly efficient catalyst for purification of volatile organic compounds with visible light irradiation

This work mainly focuses on exploring carbon coated epsilon-MnO2 (epsilon-MnO2/C) with 3D hierarchical structures for degradation of gaseous toluene under visible light. Influence of C-coating on surface adsorption, visible-light activity and photocatalytic activities of C-coated MnO2 have been investigated. The results indicate that the C-coating behave as the adsorption and electron-transfer system, and the resulting C-coated epsilon-MnO2 could extend the optical response from UV to visible light region, which can generate more electron - hole pairs. The photocatalyst epsilon-MnO2/0.45C exhibited excellent visible-light photocatalytic activities, with degradation rate of toluene up to 87.34% in 70 min, but no photocatalytic activity could be observed for the pure epsilon-MnO2. The PL spectra and photocurrent response results indicate that the composite structure can not only enhance the utilization of visible light but also consequently reduce electron (e(-))-hole (h(+)) pair recombination, which improve the photocatalytic efficiency of the composite photocatalyst. This work provides a facile and economic approach for fabricating photocatalysts with high efficiency for degradation of VOCs under visible light at room temperature. (C) 2018 Elsevier B.V. All rights reserved.