Highly conductive C12A7:e− electride nanoparticles as an electron donor type promoter to P25 for enhancing photocatalytic hydrogen evolution

Abstract

In this work, we report a comprehensive investigation on the catalytic performance and mechanism of mayenite electride [Ca24Al28O64]4+(O2−)2−x (e−)2x (C12A7:e−) as an electron donor type promoter to P25 in hydrogen production from water. Herein, the C12A7:e−–P25 composites were prepared by simply mechanical mixing method. The optimum H2 evolution rate reached 663 μmol h−1 g−1 which was 43.9 times higher than that of pure P25, when 0.25 wt% C12A7:e− was added. Mott–Schottky plots and X-ray photoelectron spectroscopic results confirmed the injection of electrons encaged in C12A7:e− to the conduction band of P25. Surface photovoltage measurements and photoluminescence results showed that the introduction of C12A7:e− promoted the efficient separation of photogenerated electron-hole pairs of P25, which illustrated the formation of built-in electric field from P25 to C12A7:e− due to the difference in work function. The present work provides new promoter choices for photocatalytic studies.