文摘
A facile and general method has been developed to fabricate oxygen vacancies on perovskite SrTiO3 (STO) nanocrystals through a controllable solid-state reaction of NaBH4 and SrTiO3 nanocrystals. STO samples with tunable color, oxygen vacancy concentration on nanocrystal surface have been synthesized. TEM results reveal that these STO samples have a crystalline core/amorphous shell structure (SrTiO3@SrTiO3鈥?i>x). XPS and EPR results disclose that the oxygen vacancy concentration increases with the increase of reaction time and temperature. The concentration of oxygen vacancies calculated from TGA data, could reach 5.07% (atom) in this study. UV鈥搗is spectra and photocatalytic results indicate that oxygen vacancies on STO surface play an important role in influencing the light absorption and photocatalytic performance. However, an excess amount of oxygen vacancies leads to a decrease of photocatalytic performance. The optimal photocatalytic activity for H2 production under UV鈥搗is irradiation is up to 2.2 mmol h鈥? g鈥?, which is about 2.3 times than the original SrTiO3, corresponding to 3.28% (atom) of oxygen vacancy concentration.
Keywords:
SrTiO3; NaBH4; oxygen vacancy; core/shell nanostructure; photocatlytic H2 generation