Effects of Zn2+ and Pb2+ dopants on the activity of Ga2O3-based photocatalysts for water splitting.
Phys Chem Chem Phys
; 15(44): 19380-6, 2013 Nov 28.
Article
in En
| MEDLINE
| ID: mdl-24121670
ABSTRACT
Zn-doped and Pb-doped ß-Ga2O3-based photocatalysts were prepared by an impregnation method. The photocatalyst based on the Zn-doped ß-Ga2O3 shows a greatly enhanced activity in water splitting while the Pb-doped ß-Ga2O3 one shows a dramatic decrease in activity. The effects of Zn(2+) and Pb(2+) dopants on the activity of Ga2O3-based photocatalysts for water splitting were investigated by HRTEM, XPS and time-resolved IR spectroscopy. A ZnGa2O4-ß-Ga2O3 heterojunction is formed in the surface region of the Zn-doped ß-Ga2O3 and a slower decay of photogenerated electrons is observed. The ZnGa2O4-ß-Ga2O3 heterojunction exhibits type-II band alignment and facilitates charge separation, thus leading to an enhanced photocatalytic activity for water splitting. Unlike Zn(2+) ions, Pb(2+) ions are coordinated by oxygen atoms to form polyhedra as dopants, resulting in distorted surface structure and fast decay of photogenerated electrons of ß-Ga2O3. These results suggest that the Pb dopants act as charge recombination centers expediting the recombination of photogenerated electrons and holes, thus decreasing the photocatalytic activity.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Phys Chem Chem Phys
Journal subject:
BIOFISICA
/
QUIMICA
Year:
2013
Type:
Article
Affiliation country:
China