fig2
![Direct Z-scheme photocatalytic systems based on vdW heterostructures for water splitting and CO<sub>2</sub> reduction: fundamentals and recent advances](https://image.oaes.cc/ba04a360-c1e8-4c19-8989-bf9420411ccd/microstructures3076.fig.2.jpg)
Figure 2. Evolution of Z-scheme heterostructures. (A) The 1st generation liquid-mediator Z-scheme heterostructures; (B) the 2nd generation solid-mediator Z-scheme heterostructures; and (C) the 3rd generation mediator-free Z-scheme heterostructures.