Controlled Construction of Supported Cu+ Sites and Their Stabilization in MIL-100(Fe): Efficient Adsorbents for Benzothiophene Capture.

ABSTRACT

Cu+-containing materials have drawn much attention in various applications because they are versatile, nontoxic, and low-cost. However, the difficulty of selective reduction and the poor stability of Cu+ species are now pretty much the agendas. Here, controlled construction of supported Cu+ sites in MIL-100(Fe) was realized under mild conditions (200 °C, 5 h) via a vapor-reduction strategy (VRS). Remarkably, the yield of Cu+ reaches 100%, which is quite higher than the traditional high-temperature autoreduction method with a yield less than 50% even at 700 °C for 12 h. More importantly, during the treatment via VRS some Fe3+ in MIL-100(Fe) are reduced to Fe2+, which prevent the frequently happened oxidation of Cu+ due to the higher oxidation potential of Fe2+. These properties make Cu+/MIL-100(Fe) efficient in the capture of typical aromatic sulfur, benzothiophene, with regard to both adsorption capacity and stability. To our knowledge, the stabilization of Cu+ using the oxidation tendency of supports is achieved for the first time, which may offer a new idea to utilize active sites with weak stability.