Deep eutectic solvothermal synthesis of an open framework copper selenidogermanate with pH-resistant Cs ion exchange properties.

Presented here is the deep eutectic solvothermal synthesis of an open framework copper selenidogermanate, namely [NH3CH3]0.75Cu1.25GeSe3 (CuGeSe-1), which exhibits a rapid and effective Cs+ ion exchange performance (qm = 225.3 mg g-1). CuGeSe-1 shows a structural flexibility upon Cs+ exchange. The robust selenide-based framework contributes to an excellent pH stability (1-12). The Cs+-laden product could be facilely eluted.