화학공학소재연구정보센터
Catalysis Letters, Vol.102, No.1-2, 69-78, 2005
Dual effects of supported W catalysts for dehydroaromatization of methane in the absence of oxygen
The screening of a series of W- based catalysts on different supports i. e. HZSM- 5, H beta, USY and Al2O3 for the dehydroaromatization of methane ( DHAM) revealed that HZSM- 5 emerged as the best support. Next, the performance of W/ HZSM- 5 and W- H2SO4/ HZSM- 5 catalysts for the DHAM reaction was compared to study the effect of acidic treatment in the impregnation method. The results showed that the optimum activity of W- H2SO4/ HZSM- 5 catalyst exceeded that of W/ HZSM- 5 catalyst. Finally, the influence of Si/ Al ratio in the W- H2SO4/ HZSM-5 catalyst was studied and the catalyst with Si/ Al ratio = 30 was found to be the most promising for the DHAM reaction. The remarkable activity of the catalyst is attributed to the presence of dual effects: suitable content of octahedral polymeric and tetrahedral monomeric tungstate species accompanied by proper amount and strength of acid sites in the catalyst.