SBA-15 mesoporous silica with different pore sizes were synthesized using Pluronic P123 (EO20PO70EO20, MAV ¼ 5800, BASF) and tetraethyl orthosilicate (TEOS) under acidic conditions, following the methodology proposed by Wang et al. [17]. 10 g of P123 were added to 350 mL of 2 M HCl solution at 35 C to obtain a clear solution. Then 21 g of TEOS were added drop wise under vigorously stirring for 48 h. The obtained white solid was recovered by vacuum filtration, washed several times with distilled water and air-dried overnight at 80 C. Organic molecules occluded in the mesopores were removed by direct calcination at 500 C with air flow for 6 h. The small pore size silica support (SBA-15-1) was synthesized without any hydrothermal treatment.