fig3

Figure 3. (A-C) Schematic representations of representative 1-D, 2-D, and 3-D oxide nanostructures, including (A) nanorods, nanowires, and nanofibers (B) nanosheets and nanoflakes, and (C) nanoflower-like, hollow, and urchin-like architectures. Schematic illustrations of (D) chemical sensitization and (E) electronic sensitization, highlighting the roles of catalytic reactions and charge transfer in enhancing gas-sensing performance. 1-D: one-dimensional; 2-D: two-dimensional; 3-D: three-dimensional.