Fundamentals, synthesis, characterization and environmental applications of layered double hydroxides: a review

The availability of clean water and energy scarcity are rising issues in the context of rising population and industrialization, calling for advanced methods of remediation and energy production. Here, layered double hydroxides, as anionic clays, can be used and engineered as adsorbents or catalysts. Layered double hydroxides are generally highly stable, safe and recyclable. They can be filled with nanomaterials to form composites of enhanced performance. Here, we review fundamentals of layered double hydroxides, synthetic protocols, and applications to energy storage, dye degradation, organic pollutant degradation, water treatment, photoelectrochemical water splitting and carbon dioxide reduction. Composites appear competitive in terms of low-cost, tunable band-gaps and high electrical conductivity.