Efficient capturing of hydrogen peroxide in dilute aqueous solution by co-crystallization with amino acids

Hydrogen peroxide (H 2 O 2 ) was efficiently captured by co-crystallization with enantiomeric and racemic amino acids such as l -phenylalanine, dl -phenylalanine, and dl -asparagine in a dilute aqueous solution of H 2 O 2 (30%) to unveil the requisites for efficient capturing of H 2 O 2 . In further dilute solutions of H 2 O 2 (0.5-20%), l -Phe provided certain amounts of co-crystals with H 2 O 2 ; however, co-crystals with H 2 O 2 were hardly obtained for dl -Phe and dl -Asn. The efficient H 2 O 2 capturing with l -Phe can be ascribed to its layered motif involving water molecules. The results obtained here would contribute to the development of an adsorbent that can efficiently capture H 2 O 2 produced in environment-friendly H 2 O 2 -production systems such as photocatalytic systems. X-ray structure analyses of co-crystals of H 2 O 2 and l -Phe, dl -Phe, or dl -Asp prepared in a dilute aqueous solution (30 wt%) indicated that multi-layer motifs including water molecule is important for highly efficient H 2 O 2 capture in dilute solutions.