Recent developments in halide perovskite based Z-scheme heterostructures for solar CO2 reduction.

Z-scheme charge transfer mechanism is thought as one of the promising concepts for photocatalyst design, to eventually commercialize photocatalytic CO2 reduction. However, the photocatalytic CO2 reduction using Z-scheme photocatalyst systems did not give the expected performance. As a case study, the halide perovskites based photocatalyst with Z-scheme configuration is reviewed here. Approaches to stabilize halide perovskites are also reviewed. Finally, it has been uniquely visualized why Z-scheme photocatalytic systems do not exhibit the expected photocatalytic activity. It will be clarified what the real hurdles are, and what practical solutions can be proposed.