Recent progress in layered double hydroxides-derived catalysts for selective reduction of nitrogen oxides by ammonia

The catalysts derived from layered double hydroxides (LDHs) have exhibited outstanding performance for the selective catalytic reduction (SCR) of nitrogen oxides (NO_x) by ammonia (NH₃) due to their various advantages, such as large specific surface area (SSA), flexible tunability, and good stability. In this review, starting from the reaction mechanism of SCR denitrification (de-NO_x) by NH₃, the structure, properties and preparation methods of LDHs are introduced. Then, the applications in NH₃-SCR de-NO_x and the advantages and disadvantages of LDHs with various active components are reviewed. Furthermore, the effects of various toxic components (SO₂/H₂O, alkali metal/alkaline earth metal, heavy metal, hydrogen chloride and phosphorus) on the de-NO_x performance of the catalysts in flue gas are reviewed, and some related anti-poisoning methods are proposed. Finally, for the poisoned catalyst, several regeneration treatment processes are summarized to restore the activity of the catalysts. It is expected that this review will help the academic and industrial circles understand the research status of novel LDHs-derived SCR catalysts, and propose reasonable design strategies for the development of more promising LDHs-derived de-NO_x catalysts. (Figure presented.).