As shown in Fig. 3 and Table 2, the superior catalytic performance of
the RHA800 support catalyst was mainly owing to more content of SiO2
and Ca2SiO4 crystalline phase, the highest total basicity and BET surface
area. It was reported that SiO2 had insufficient catalytic activity, which
could be enhanced by loading with CaO. This is primarily because the
formed CaO–SiO2 phase had high basicity and sufficient catalytic