A new method to synthesis TS-1 has been developed using the carbon dioxide (CO2) as an alkalinity regulator that resulted in the increased framework Ti contents. The prepared catalyst had a Si/Ti ratio as low as 40 in contrast to the ratio of 56 prepared through conventional synthesis. The twin crystals with the length of 2 μm were formed via introduction of CO 2. The catalytic activity of TS-1 is remarkably enhanced compared with the conventional synthesis. © 2013 Elsevier B.V.