Search

In this paper, a facile hydrothermal synthesis of precursor MnO2and subsequent high-temperature calcination has been used to prepare sea-urchin-like Mn2O3.The influences of calcination temperatures on the structures and electrochemical performances of Mn2O3are clearly studied. The results show that the elevated temperature helps to improve the crystallinity and particle size, the 700°C sample shows an optimal electrochemical performance. Therein, a high discharge capacity of 765.7 mAh g− 1can be retained after 50 cycles at 200 mA g− 1, and a value of 465.8 mAh g− 1can be kept at 800 mA g− 1.More importantly, a surprised calcination temperature determines phenomenon that discharges capacity increase upon cycles can be observed, which may be useful for the design and nanostructured of Mn-based oxides as lithium-ion battery anodes. [ABSTRACT FROM AUTHOR]

Mn 2 O 3 is a conventional catalyst that is applied in photothermal catalytic oxidation of toluene while regular anions like SO 4 2-, Cl-, and NO 3 - from different Mn precursors are left in Mn 2 O 3. When applied in toluene degradation, the declining activity of Mn 2 O 3 is always observable because the residual anions block the Mn4+/Mn3+ active sites, shield the oxygen vacancies, and cube the production of active oxygen species (O 2 -, O-). Herein, it is found that the residual SO 4 2-, Cl-, and NO 3 - make Mn 2 O 3 incapacitated in deeply oxidizing the intermediates and cutting off the reaction process, and their influence ranks in the order of SO 4 2->Cl->NO 3 -. Compared with pristine Mn 2 O 3 , the drops in CO 2 conversion efficiency account for 11 %, 60 %, and 73 %, respectively. Nevertheless, rinsing with water is an effective method to remove the residual anions, and the more the rinsing, the better the toluene mineralization degree. This work provides a profound cognition of the deactivation mechanism of SO 4 2-, Cl-, and NO 3 - and points out an effective way to abate their negative effect for the first time. [Display omitted] • NO 3 - poses a neglectable impact on Mn 2 O 3 's catalytic activity. • SO 4 2- and Cl- anions cover the OVs and active sites, causing reduced catalytic properties. • Multiple rinsing washes the anions away from MnC 2 O 4 to endow high activity of Mn 2 O 3. [ABSTRACT FROM AUTHOR]