Exploration of new water stable proton-conducting materials in an amino acid-templated metal phosphate system

Abstract

Two new metal phosphates, namely, Zn(HPO₄)(DL-C₃H₇NO₂) (SCU-4) and In(HPO₄)(H₂PO₄)(DL-C₃H₇NO₂) (SCU-12), were prepared in the presence of the amino acid L-alanine. SCU-4 has a ladderlike structure with edge-sharing 4-rings. SCU-12 represents the first example of a three-dimensional metal phosphate templated by an amino acid. It remains stable in boiling water and shows a high proton conductivity at room temperature under 98% relative humidity.