CuI-Functionalized materials show high potential in numerous applications such as adsorptive desulfurization. Nonetheless, the instability of CuI against oxidation limits its practical applications, and exposure of CuI to air can lead to the formation of CuII owing to the presence of oxygen and moisture. Herein, an unexpected way to stabilize CuI against oxidation was designed by constructing a superhydrophobic microenvironment in original hydrophilic metal–organic frameworks (MOFs) via polystyrene (PS) coating. A pre-polymerization strategy is developed to coat PS on the surface of CuI-functionalized MIL-101(Cr) (CuIM) rather than entering the pores (producing CuIM@PS), and the access of moisture to CuI is hindered, thus stabilizing CuI regardless of the existence of oxygen. CuI in CuIM@PS is stable in the air with a constant relative humidity of 75% for 200 days, while almost all CuI is converted to CuII in CuIM in only 14 days. The optimal CuIM@PS material after air exposure can adsorb 0.208 mmol g−1 of thiophene, which is much superior to that of CuIM (0.024 mmol g−1) despite the comparable adsorption capacity for unexposed materials. Moreover, the present CuIM@PS adsorbents exhibit excellent adsorption performance for water-containing model fuels.
