"On-the-fly" synthesis of self-supported LDH hollow structures through controlled microfluidic reaction-diffusion conditions

Layered double hydroxides (LDHs) are a class of functional materials that exhibit exceptional properties for diverse applications in areas such as heterogeneous catalysis, energy storage and conversion, and bio-medical applications, among others. Efforts have been devoted to produce millimeter-scale LDH structures for direct integration into functional devices. However, the controlled synthesis of self-supported continuous LDH materials with hierarchical structuring up to the millimeter scale through a straightforward one-pot reaction method remains unaddressed. Herein, we show that millimeter-scale self-supported LDH structures can be produced by means of a continuous flow microfluidic device in a rapid and reproducible one-pot process. Additionally, our microfluidic approach not only allows for an ‘on-the-fly’ formation of unprecedented LDH composite structures, but also for the seamless integration of millimeter-scale LDH structures into functional devices. Our method holds the potential to unlock the integrability of these materials, maintaining their performance and functionality, while diverging from conventional techniques like pelletization and densification that often compromise these aspects. Our strategy will enable exciting advancements in LDH performance and functionality.