Functionalization of metal–organic frameworks with cuprous sites using vapor-induced selective reduction: efficient adsorbents for deep desulfurization. Issue 11 (25th April 2016) - Qin, Ju-Xiang
Abstract : Efficient, controllable conversion of Cu(ii ) to Cu(i ) was realized on metal–organic frameworks by using a vapor-induced selective reduction strategy. Abstract : Functionalization of metal–organic frameworks (MOFs) with Cu(i ) sites is extremely desirable for various applications including adsorption, catalysis, and sensing. The traditional method for the conversion of supported Cu(ii ) to Cu(i ) is high-temperature autoreduction (HTA), which produces Cu(i ) with an unsatisfactory yield ( ca . 50%) but requires quite harsh conditions ( e.g. 700 °C, 12 h) that are unsuitable for MOFs. Here we report the rational design of an efficient, controllable strategy for the conversion of supported Cu(ii ) to Cu(i ) by using vapor-induced selective reduction (VISR), in which vapors of weak reducing agents ( e.g. methanol) diffuse into the pores of MOFs and interact with Cu(ii ) precursors. This strategy allows the fabrication of Cu(i ) sites with a 100% yield without the formation of Cu(0) at much lower temperatures ( e.g. 200 °C, 6 h) and subsequently preserves the structure of MOFs well. Due to the abundant Cu(i ) sites and high porosity of MOF supports, the obtained materials exhibit excellent performance in adsorptive desulfurization with regard to capacity, selectivity, and recyclability.