The precursors prepared from different solvents were characterized
by TG and DSC. As shown in Fig. 2, the weight loss at low temperature
(473 K) should be attributed to removing the absorbedwater. It is clearly
found that the DSC pattern of the Co/MnOx-BDO sample exhibited
two strong exothermic peaks at 488 K and 508 K, which should include
the combustion of the absorbed BDO [13], and partial decomposition of
catalyst precursors. However, for precursor of Co/MnOx-H2O, there are
no obvious exothermic peaks at 473–523 K.
The Co/MnOx-BDO has only one strong thermal decomposition peak
located at 550–700 K, where there are three endothermic peaks of the
Co/MnOx-H2Owith almost the same intensity, indicating that the decomposition
of precursors and formation of oxide for Co/MnOx-H2Ocontained
several steps including step-by-step decomposition of precursors and aggregation
of oxide particles. The last two stages of weight loss around
753–923 K should be due to the crystal transition ofmanganese oxides.
Based on these findings, it is considered that the heat released uniformly
from combustion of absorbed BDOwas quickly absorbed by the precursor
of catalyst to supply energy for decomposition of precursors and formation
of oxide particles, which was advantageous to the formation of relatively
homogeneous oxide particles and preventing the aggregation of
primary particles during calcinations, resulting in the forming of uniformly
distributed pore size of Co/MnOx-BDO catalyst