COMPARATIVE STUDY OF THE PHYSICOCHEMICAL PROPERTIES AND PHOTOCATALYTIC ACTIVITY OF MODIFIED MCM-41 SYNTHESIZED BY DIRECT (ONE-STEP) INCORPORATION AND IMPREGNATION

摘要

MCM-41 structures were synthesized and modified by direct (one-step) incorporation (DI) and wet impregnation (WI) methods. The solids were characterized by XRF, XRD, N2 adsorption and UV-Vis DR, and catalytically evaluated in the Acid Orange 7 (AO7) degradation under visible light. Significant influence of the presence, dispersion and location of the different Cr species on photoactivity was evident. Both synthesis methods allowed greater dispersion of the photoactive Cr species for lower metal content, enhancing efficiency for dye degradation. More specifically, after Ti loading in samples synthesized by DI, a notable AO7 degradation increase was associated with the strong heterojunction between Ti and Cr6+ species, which wereare highly dispersed due to the DI method used.