Amorphous K–Co–Mo–Sx Chalcogel: A Synergy of Surface Sorption and Ion‐Exchange

Abstract

AbstractChalcogel represents a unique class of meso‐ to macroporous nanomaterials that offer applications in energy and environmental pursuits. Here, the synthesis of an ion‐exchangeable amorphous chalcogel using a nominal composition of K2CoMo2S10 (KCMS) at room temperature is reported. Synchrotron X‐ray pair distribution function (PDF), X‐ray absorption near‐edge structure (XANES), and extended X‐ray absorption fine structure (EXAFS) reveal a plausible local structure of KCMS gel consisting of Mo5+2 and Mo4+3 clusters in the vicinity of di/polysulfides which are covalently linked by Co2+ ions. The ionically bound K+ ions remain in the percolating pores of the Co–Mo–S covalent network. XANES of Co K‐edge shows multiple electronic transitions, including quadrupole (1s→3d), shakedown (1s→4p + MLCT), and dipole allowed 1s→4p transitions. Remarkably, despite a lack of regular channels as in some crystalline solids, the amorphous KCMS gel shows ion‐exchange properties with UO22+ ions. Additionally, it also presents surface sorption via [S∙∙∙∙UO22+] covalent interactions. Overall, this study underscores the synthesis of quaternary chalcogels incorporating alkali metals and their potential to advance separation science for cations and oxo‐cationic species by integrating a synergy of surface sorption and ion‐exchange.