摘要
Oxygen vacancy（VO） plays a vital role in semiconductor photocatalysis. Rutile TiO2 nanomaterials with controllable contents of VO（0–2.18%） are fabricated via an insitu solid-state chemical reduction strategy, with color from white to black. The bandgap of the resultant rutile TiO2 is reduced from 3.0 to 2.56 e V, indicating the enhanced visible light absorption. The resultant rutile TiO2 with optimal contents of VO（2.07%） exhibits a high solar-driven photocatalytic hydrogen production rate of 734 μmol h-1, which is about four times as high as that of the pristine one（185 μmol h-1）. The presence of VOelevates the apparent Fermi level of rutile TiO2 and promotes the efficient electronhole separation obviously, which favor the escape of photogenerated electrons and prolong the life-time（7.6×103 ns） of photogenerated charge carriers, confirmed by scanning Kelvin probe microscopy, surface photovoltage spectroscopy and transient-state fluorescence. VO-mediated efficient photogenerated electron-hole separation strategy may provide new insight for fabricating other high-performance semiconductor oxide photocatalysts.
氧空位缺陷在半导体光催化中起重要作用.本文采用原位固态化学还原策略可控制备了具有不同氧空位含量(0~2.18%)的金红石TiO_2纳米材料,其带隙由3.0 eV减小到2.56 eV,颜色由白色变为黑色.氧空位含量为~2.07%的样品具有最高的太阳光催化产氢性能(734μmol h^(-1)),产氢量约为原始样品(185μmol h^(-1))的四倍.扫描开尔文探针、表面光电压和瞬态荧光结果表明:氧空位的出现提升了金红石TiO_2的表观费米能级并促进了光生电子-空穴的分离,有利于光生电子的溢出和光生载流子寿命的延长(7.6×10~3ns).这种由氧空位缺陷诱导的光生电子-空穴高效分离策略为构筑其他高性能半导体氧化物光催化剂提供了新思路.
基金
supported by the Key Program Projects of the National Natural Science Foundation of China (21631004)
the National Natural Science Foundation of China (51672073)
