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

Abstract

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 α-MnO2 nanofiber was developed. The optimized catalyst exhibited a stable ozone conversion efficiency of 80% and excellent stability over 100 h 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 α-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.

Recent progresses in the synthesis of MnO2 nanowire and its application in environmental catalysis

“…They found that α-MnO 2 performed the highest ozone removal efficiency. Zhu et al 203 developed a hierarchical structure consisted of graphene encapsulating α-MnO 2 nanofiber to address the challenges of the low stability and water inactivation during ozone decomposition. The optimized catalyst exhibited high ozone conversion efficiency of 80% and excellent stability over 100 h under a relative humidity (RH) of 20%.…”

Interfacial tension driven adsorption of MnO2 nanoparticles at the liquid/liquid interface to tailor ultra-thin polypyrrole sheets

“…† Furthermore, the corresponding selected area electron diffraction patterns support the formation of the tetragonal structure of α-MnO 2 . 32,54,60,61 The planes (002), ( 200), ( 211), ( 220), (310), (400), (402), (411), ( 431), (440), (521), (541), (600), (602), (710), (730), and (741) are reported for α-MnO 2 (JCPDS no. 00-044-0141).…”

“…24 The peaks at 2θ = 13.461°, 20.874°, 28.829°, 37.507°, 62.818°, 69.688°, 77.101°, and 84.152°can be attributed to the Bragg diffractions caused by the (110), ( 200), (310), ( 211), ( 521), ( 541), ( 402) and (512) planes, respectively. 32,54,60 The XRD spectrum (Fig. 4E) and SAED pattern (Fig.…”

CFD Simulation Using ANSYS FLUENT of Jet Nozzle of Ethanol at Temperature of 360 K

“…Development of new carbon material such as CNT, graphene oxide (GO) and reduced-GO (RGO) for new applications such as sensors, electronic devices, superconductors, catalysts, etc. have been widely investigated due to their high thermal and chemical stability, high aspect ratio and unique electronic properties, see studies by Zhang and Nicolosi [7], Szuromi [8], and Zhu et al, [9]. The fabrication methods used to form a film or layer on the glass or silicon substrate of these unique materials were chemical vapor deposition (CVD), spray coating, sputtering, or dipping techniques.…”