Lanthanoid oxide modifier layers were applied to Rh metal nanoparticles on (Ga1-xZnx)(N1-xOx) photocatalyst for overall water splitting under visible-light irradiation. Structural analysis by transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy revealed that lanthanoid(III) oxide layers coated the Rh nanoparticles on (Ga 1-xZnx)(N1-xOx), although they were also deposited directly on the (Ga1-xZnx)(N 1-xOx) surface. Certain lanthanoid oxide layers (La, Pr, Sm, Gd, and Dy) functioned as modifiers for Rh-metal/(Ga1-xZn x)(N1-xOx) to produce H2 and O 2 gases, although the Rh-metal/(Ga1-xZn x)(N1-xOx) photocatalyst exhibited little activity for overall water splitting due to rapid water formation from H 2 and O2 on Rh. Ce and Eu oxide layers showed no photocatalytic activity, most likely due to their ability to capture photoexcited electrons from Rh-metal/(Ga1-xZnx)(N 1-xOx). The enhancement of photocatalytic activity by lanthanoid oxide loading was shown to be dependent on the formation of redox-inactive lanthanoid(III) oxide layers on the Rh nanoparticles, which effectively suppresses the backward water formation reaction to enable H 2 evolution on Rh.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films