Spatial Heterojunction in Nanostructured TiO<sub>2</sub> and Its Cascade Effect for Efficient Photocatalysis
Yi Lu, Xiaolong Liu, He Li, Yuexing Zhang, Zhi-Yi Hu, Ge Tian, Xiu Cheng, Si-Ming Wu, Yuan-Zhou Li, Xiao-Hang Yang, Xiao-Hang Yang, Liying Wang, Jia-Wen Liu, Christoph Janiak, Ganggang Chang, Weihua Li, Gustaaf Van Tendeloo, Xiao-Yu Yang, Xiao-Yu Yang, Bao‐Lian Su
Abstract
A highly efficient photoenergy conversion is strongly dependent on the cumulative cascade efficiency of the photogenerated carriers. Spatial heterojunctions are critical to directed charge transfer and, thus, attractive but still a challenge. Here, a spatially ternary titanium-defected TiO2@carbon quantum dots@reduced graphene oxide (denoted as VTi@CQDs@rGO) in one system is shown to demonstrate a cascade effect of charges and significant performances regarding the photocurrent, the apparent quantum yield, and photocatalysis such as H2 production from water splitting and CO2 reduction. A key aspect in the construction is the technologically irrational junction of Ti-vacancies and nanocarbons for the spatially inside-out heterojunction. The new “spatial heterojunctions” concept, characteristics, mechanism, and extension are proposed at an atomic-/nanoscale to clarify the generation of rational heterojunctions as well as the cascade electron transfer.