10.1039/c5cy02011e
Promotional effect of HZSM-5 on the catalytic oxidation of toluene over MnOx/HZSM-5 catalysts
 Firstly, the HZSM-5 (Si/Al = 50) zeolite was prepared by a conventional hydrothermal method. Tetraethyl orthosilicate (TEOS, Sinopharm AR, 15.6 g) was added into a solution containing water (7 g), sodium aluminate (NaAlO2, Sinopharm AR, 0.123 g) and tetrapropylammonium hydroxide (TPAOH, Aladdin 25 wt% in water, 12.18 g). After being stirred at 30 degC for 5 h, the resulting mixture was transferred into a Teflon-lined autoclave with hydrothermal treatment at 120 degC for 2 h and 170 degC for 24 h in an electric oven. Then, the solid product was collected by centrifugation and calcined at 550 degC for 8 h to remove the TPA+ species, resulting in the formation of Na-type ZSM-5 (NaZSM-5). Finally, H-type ZSM-5 (HZSM-5) was obtained by three consecutive ion exchanges in 1 M NH4NO3 aqueous solution and subsequent calcination in static air at 550 degC for 8 h.
HZSM-5
Si/Al
50
Tetraethyl orthosilicate (TEOS
added
15.6 g
g
water
7 g
g
tetrapropylammonium hydroxide (TPAOH
in water
25 wt%
wt%
solution
sodium aluminate (NaAlO2
0.123 g
g
solution
tetrapropylammonium hydroxide (TPAOH
12.18 g
g
resulting mixture
hydrothermal treatment
120 degC for 2 h and 170 degC
degC
resulting mixture
hydrothermal treatment
2 h and 170 degC for 24 h
h
mixture
stirred
5 h
h
mixture
stirred
30 degC
degC
solid product
calcined
550 degC
degC
solid product
calcined
8 h
h
calcination in static air
550 degC
degC
calcination in static air
8 h
h
NH4NO3 aqueous solution
three consecutive ion exchanges
1 M
M