Fabrication of Cu+ sites in confined spaces for adsorptive desulfurization by series connection double-solvent strategy

Cu+-containing materials have shown various application prospects especially in adsorption and catalysis, because they are versatile, non-toxic and low cost. To date, developing a mild and controllable approach for the fabrication of Cu+ sites has remained a pronounced challenge. Herein, we report a series connection double-solvent strategy (SCDS) for fabricating Cu+ sites within MIL-101(Cr), a typical metal–organic framework. By employing the SCDS in which vitamin C is chosen as the environmentally benign reducing agent, Cu2+ was incorporated in the pores and then transformed to Cu+ in the confined spaces. Compared to the conventional high-temperature autoreduction method conducted under harsh environment (700 °C for 12 h) with a low Cu+ yield (less than 50%), SCDS can selectively reduce Cu2+ to Cu+ at room temperature without generating any Cu0. The resulting Cu+ modified MIL-101(Cr) exhibits good desulfurization performance in view of both uptake and recyclability.