Crystalline defects of photocatalyst particles may be considered to be the recombination center of photoexcited electrons and holes. In this study, we investigated the photocatalytic activity of cation-doped rutile TiO₂ photocatalysts for O₂ evolution from an aqueous silver nitrate solution under ultraviolet light irradiation. The photocatalytic activity of rutile TiO₂ was enhanced by donor doping of Ta⁵⁺ and Nb⁵⁺ with a valence higher than that of Ti⁴⁺, regardless of increased density of electrons and Ti³⁺ species (an electron trapped in Ti⁴⁺ sites). Conversely, acceptor doping of lower valence cations such as In³⁺ and Ga³⁺ decreased photocatalytic activity for O₂ evolution by water oxidation. The doping of equal valence cations such as Sn⁴⁺ and Ge⁴⁺ hardly changed the activity of non-doped TiO₂. This study demonstrates that Ti³⁺ species, which is a crystalline defect, enhanced the photocatalytic activity of semiconductor oxides, for example rutile TiO₂ with large crystalline size.

光催化剂颗粒的晶体缺陷可以被认为是光激发电子和空穴的复合中心。在这项研究中，我们研究了阳离子掺杂的金红石型TiO ₂光催化剂对紫外光下硝酸银水溶液中O ₂析出的光催化活性。Ta ⁵⁺和Nb ⁵⁺的供体掺杂^价比Ti ⁴⁺高，金红石TiO ₂的光催化活性得以增强，而与电子和Ti ³⁺物种（被困在Ti ^4+中的电子的密度增加）无关。网站）。相反，低价阳离子如In ^3+的受体掺杂Ga ³⁺降低了水氧化过程中O ₂^析出的光催化活性。等价阳离子如Sn ⁴⁺和Ge ⁴⁺的掺杂几乎不会改变非掺杂TiO ₂的活性。这项研究表明，作为晶体缺陷的Ti ³⁺物种增强了半导体氧化物（例如具有大晶体尺寸的金红石TiO _2）的光催化活性。