Vacancy-ordered chloride perovskites for reversible release–storage of chlorine

Elemental chlorine plays an irreplaceable role in many fields such as scientific study and the chemical industry. However, the highly toxic, corrosive, and volatile characteristics of Cl 2 increase the risks of leakage or explosion in chlorine storage and transportation. Using bulk materials to solidify Cl 2 is conduce to release chlorine gas on-demand securely. Herein, several vacancy-ordered chloride perovskites (i.e., Cs 2 PbCl 6 , Rb 2 PbCl 6 , (NH 4 ) 2 PbCl 6 , and Cs 4 Sb 2 Cl 12 ) for elemental chlorine solidification were synthesized by a Cl 2 -free solvothermal method. The experimental and theoretical results indicate that the release–storage of Cl 2 gas depends on the reversible redox between metal cations and chloridion. Both thermal heating and solvent soaking could trigger the release of Cl 2 in perovskites. The stability and Cl 2 storage performance (from 5.9 wt % to 16 wt %) of vacancy-ordered chloride perovskites can be tuned by composition engineering. Compared with the porous adsorption materials, Cs 2 PbCl 6 has the highest reversible storage capacity of Cl 2 . Graphical Abstract