Constructing metal single-atom-mediated Z-scheme charge transmission is a promising yet challenging avenue to realize efficient solar photocatalysis. Here, a single-atom Cu-bridged TiO2 hetero-phase assembly with opened cavities and Z-scheme charge transmission is fabricated via the illumination-assisted preparation recipe. When tested for gas-solid photocatalytic CO2 conversion, our photocatalyst displays an extraordinary activity with CH4 production rate reaching to 327.19 µmol·g-1·h-1, roughly 15.6 and 122.1 times enhancement than Degussa P25 TiO2 and TiO2(B), and it outperforms those of Cu nanoparticles, Pd single atoms, Pt nanoparticles, Pd nanoparticles, and Au nanoparticles-loaded counterparts as well as most TiO2-based composites ever reported. Based on the experimental test and theoretical calculation results, Cu single atoms act as the mediator to enhance interfacial charge transfer, which changes the photo-carrier transmission pathway from type-II to Z-scheme, accounting for the significant promotion of photocatalytic capability. The study results could propel the marked optimization of photocatalytic efficiency by steering Z-scheme charge transport with a single-atom mediator.
Lin et al. (Mon,) studied this question.