Lanthanide-doped layered double hydroxides and method of producing same

A method for producing lanthanide doped layered double hydroxides (Ln-doped LDHs), the method comprising:

• a) preparing a carbonate free alkaline solution;
• b) preparing a solution of metal salts comprising a salt of a lanthanide;
• c) adding the alkaline solution and the solution of metal salts to form a mixture, wherein a speed of adding the alkaline solution or of adding the solution of metal salts is set such that a pH of the mixture is maintained at a constant value so as to form Ln-doped LDH precipitate;
• d) aging the precipitate;
• and
• e) separating the precipitate from the mixture;
• wherein the carbonate free alkaline solution is an aqueous ammonia solution;
• and
• wherein the lanthanide doped layered double hydroxides have a crystal structure having a unit cell with lattice parameter a110 at least 1.6% larger than lattice parameter a110 of a unit cell of the crystal structure of layered double hydroxides that are not lanthanide doped.