Improvement on the mesostructural ordering and catalytic activity of Co-MCM-41 with ascorbic acid as auxiliary

• A series of Co-MCM-41 with different cobalt contents were synthesized.
• The addition of ascorbic acid makes the mesoporous structure become more regular.
• More cobalt atoms were incorporated in the framework of MCM-41.
• The catalytic activity in the hydroxylation of benzene was improved more efficiently.

A series of Co-MCM-41 with different cobalt contents were synthesized with ascorbic acid as auxiliary by direct hydrothermal synthesis, in which surprising promotion effect of the ascorbic acid on the long-range ordering of mesoporous structure and its crucial contribution to the catalytic activity were validated. Without the assistance of ascorbic acid, we were unable to synthesize the Co-MCM-41 mesoporous silica with Co/Si molar ratio greater than 0.15, while it is possible for us to obtain sample with Co/Si molar ratio up to 0.30 and more cobalt atoms anchored in the framework of Co-MCM-41 with the assistance of ascorbic acid. Meanwhile, its catalytic activity in the direct hydroxylation of benzene with hydroperoxide as oxidant was highly improved.