Pore-size-dependent adsorption of HCrO4− and Cr2O72− towards sustainable supported Cr(III) catalysts through in-situ reduction

Hexavalent chromium has seriously destroyed the natural environment and threatened human health. It is crucial but still challengeable to dispose of Cr(VI) handily and recycle the as-generated Cr-based byproducts. Herein, on the one hand, we demonstrate a feasible strategy for cyclic utilization of Cr(VI) species by converting them from toxic to trash and further to treasure. Multiamino-functionalized dendritic mesoporous silica nanoparticles (DMSNs) can adsorb chromium oxyanion ions (HCrO 4 − and Cr 2 O 7 2– ) and in situ reduce Cr(VI) to Cr(III). The as-obtained DMSNs-Cr(III) function as supported catalysts and efficiently catalyze some cross-coupling reactions. On the other hand, pore-size-dependent adsorption of HCrO 4 − and Cr 2 O 7 2− has been realized by regulating DMSNs’ channel size. Furthermore, pore-size-dependent adsorptive and catalytic performances have been demonstrated as well. Our results not only provide a blueprint for cyclic utilization of Cr(VI) in sewage, but also exhibit a versatile DMSNs-based platform that couples with potential structure–activity correlations.