Toward efficient photocatalysts for light-driven CO₂reduction: TiO₂nanostructures decorated with perovskite quantum dots

Nanostructured TiO2 is often used for photocatalytic CO2 conversion due to its favorable electronic properties and stability, being coupled with large surface area and unique electrical properties. However, pure TiO2, without any expensive cocatalysts, can not provide highly efficient CO2 conversion because its bandgap and resulted limited numbers of photogenerated electrons and holes limit efficient energy conversion. Here, we demonstrate TiO2 nanotube (TNT) photocatalysts equipped with two different perovskite quantum dots (PQDs) made of CH3NH3PbBr3 and CH3NH3PbI3. The fundamental properties of the PQDs and TNT/PQD photocatalysts are investigated and their potential for more efficient CO2 conversion are discussed, to our best knowledge, for the first time. TNT/CH3NH3PbI3 QD photocatalysts absorb a wider range of light energy and show superior charge transport characteristics due to less sensitivity against surface states at TNT/CH3NH3PbI3 QD interface than the TNT/CH3NH3PbBr3 photocatalysts.