Tailoring the morphology and crystal facet of Mn3O4 for highly efficient catalytic combustion of ethanol

Three nanoscale Mn3O4 with different morphologies (hexagonal nanoplates, nan-octahedrons and nano-flowers) have been prepared and evaluated for total combustion of ethanol. The hexagonal nanoplates (Mn3O4-HNS) catalyst showed highly enhanced catalytic performance at a high space velocity (SV) (66,000 mL/(g.h)) compared to nan-octahedrons (Mn3O4-ONS) and nano-flowers (Mn3O4-FNS). The catalysts were characterized by XRD, BET, FE-SEM, HR-TEM, H-2-TPR, XPS and ethanol-TPD. The morphology-dependent reactivity was well correlated with the exposure degree of Mn3O4 (112) crystal facet determined by HR-TEM The experimental characterization results indicated that the (112) crystal facet with high surface energy can not only facilitate the adsorption/activation of ethanol and oxygen, but also be favorable for formation of more surface Mn4+ and active oxygen species. Thus, the oxidation activity of ethanol was significantly improved. This study proposes that the strategy of crystal facet engineering can be used as the design principles of developing high performance, low cost and environmentally friendly manganese oxides catalysts.

Automated summary

Three nanoscale Mn3O4 catalysts with different morphologies were prepared and evaluated for ethanol combustion. The hexagonal nanoplates catalyst showed enhanced performance due to the (112) crystal facet with high surface energy, facilitating adsorption/activation of ethanol and oxygen. This study suggests that crystal facet engineering can be used to develop high performance, low cost, environmentally friendly manganese oxides catalysts.