Multiscale structural control of thiostannate chalcogels with two-dimensional crystalline constituents
Thanh Duy Cam Ha, Heehyeon Lee, Yeo Kyung Kang, Kyunghan Ahn, Hyeong Min Jin, In Jae Chung, Byungman Kang, Youngtak Oh, Myung‐Gil Kim
Abstract
Abstract Chalcogenide aerogels (chalcogels) are amorphous structures widely known for their lack of localized structural control. This study, however, demonstrates a precise multiscale structural control through a thiostannate motif ([Sn 2 S 6 ] 4− )-transformation-induced self-assembly, yielding Na-Mn-Sn-S, Na-Mg-Sn-S, and Na-Sn(II)-Sn(IV)-S aerogels. The aerogels exhibited [Sn 2 S 6 ] 4− :Mn 2+ stoichiometric-variation-induced-control of average specific surface areas (95–226 m 2 g −1 ), thiostannate coordination networks (octahedral to tetrahedral), phase crystallinity (crystalline to amorphous), and hierarchical porous structures (micropore-intensive to mixed-pore state). In addition, these chalcogels successfully adopted the structural motifs and ion-exchange principles of two-dimensional layered metal sulfides (K 2 x Mn x Sn 3- x S 6 , KMS-1), featuring a layer-by-layer stacking structure and effective radionuclide (Cs + , Sr 2+ )-control functionality. The thiostannate cluster-based gelation principle can be extended to afford Na-Mg-Sn-S and Na-Sn(II)-Sn(IV)-S chalcogels with the same structural features as the Na-Mn-Sn-S chalcogels (NMSCs). The study of NMSCs and their chalcogel family proves that the self-assembly principle of two-dimensional chalcogenide clusters can be used to design unique chalcogels with unprecedented structural hierarchy.