Shape-controlled synthesis of Mn2O3 hollow structures and their catalytic properties

Abstract

A series of MnCO₃ and MnC₂O₄ microstructures were fabricated via a self-templated method, in which carbon spheres obtained by a carbonization process in the same solution served as cores and templates. The shape of carbon@MnCO₃/MnC₂O₄ evolved from rhombi, to ellipsoids, to dumbbells, and to twin-sphere particles, depending on the setting time and temperature of the pre-mixing period. The carbon core was completely removed after calcination at 550 °C, and a phase transformation to Mn₂O₃ hollow microstructures was achieved, retaining their original shapes. The catalytic activities of the as-obtained Mn₂O₃ hollow microstructures for CO oxidation were examined. The catalytic activities decreased in the order of Mn₂O₃ ellipsoids ≈ dumbbells > twin spheres > rhombi.