Dual-Functional Ice/Water Interface Allows High-Yield Formation of Al13 with Low Energy

Keggin Al13[(AlO4Al12(OH)24(H2O)12]7+ is a well-known efficient coagulant widely used in water purification and treatment. The production of high-content Al13 is still costly, and it is therefore essential to develop new eco-efficient and low energy demand synthesis methods for practical application. Solid–water interfaces play a dominant role in heterogeneous reactions, which can be utilized in various processes through rationally designed interfaces. Here, we designed an Al3+ and OH– interface by using NaOH-doped ice as a solid and AlCl3 solution as liquid for Al13 production. This system provides a natural and renewable solid–water interface through ice melting, while simultaneously minimizing external energy input and maintaining an effective heterogeneous interface reaction for production of high-quality Al13 species. The dual-function of ice/water interface enables the formation of Al13 with a high yield of up to 90% compared to initial total Al. Moreover, global areas with cold winter climate condi...