Ultralow Fe doping induced high photocatalytic activity toward ciprofloxacin degradation and CO2 reduction

TiO 2 is one of the most ideal photocatalytic materials, but its application is limited by many problems (e.g., wide band gap, easy carrier recombination). Co-catalyst with changes in valence could efficiently overcome the disadvantages above. Herein, a Fe species (Fe, Fe 2 O 3 )/TiO 2 was designed to fully utilize photogenerated charges and holes. The degradation rate of ciprofloxacin can reach 99.97%. In addition, its methane generation from photoreduction of CO 2 is 12.9 times than that of pure TiO 2 . These results are attributed to the well-designed catalyst including the combination of TiO 2 and FeO x as photocatalysts and oxygen buffers, and the dispersion of single-atom Fe clusters as cocatalysts and electron trap sites. The effect mechanism of Fe species on TiO 2 was verified by PBE DFT calculation. Finally, following a concept of thermodynamic-kinetic synergy, a new design strategy for photocatalysts is accordingly proposed, as such, the prepared catalyst is expected to be applied in the environmental remediation.