Research / 2022 / Article / Fig 2

Research Article

Direct Electron Transfer from Upconversion Graphene Quantum Dots to TiO2 Enabling Infrared Light-Driven Overall Water Splitting

Figure 2

Morphology and microstructure characterization of the samples. (a) TEM image and (b) Raman spectrum of the obtained GQDs. The inset of (a) shows the size distribution. (c) TEM image and (d) HRTEM images of the obtained TiO2 nanotubes. The inset of (c) shows the BET result. (e) TEM image and (f) elemental mapping profiles of the obtained TiO2/GQDs (scale bars are 10 nm). The inset of (e) shows the BET result. (g) TEM image, (h) elemental mapping profile, (i) EDX spectrum, (j–l) HRTEM images, and (m, n) AC-TEM images of the obtained TiO2/r-GQDs. (o) Valence-band spectra measured by XPS and (p) band structures of the three samples.