context: (4) Photoelectrocatalysis (PEC): PEC is a special electricity-driven photocatalytic process which could be regarded as a combination of electrocatalysis and photocatalysis. In a typical PEC cell, the photocatalysts are usually immobilized on a conductive substrate as the anode and a bias potential as well as continuous illumination are then applied to the prepared anode to generate functional radicals to remove the contaminants. In particular, it should be mentioned that the separation of photo-induced charge carriers could be significantly enhanced by the utilized bias potential since the electrons generated by photocatalysis follow the electric field to the cathode, which contributes to the reduction of the recombination rate. As a result, the photoelectrocatalytic method would significantly promote the degradation efficiency of the titanate materials. For example, Chang et al. synthesized a Cu2O/titanate composite for photocatalytic and photoelectrocatalytic degradation of ibuprofen. The results indicated that the pseudo-first rate constant could be increased from 0.804 h−1 for photocatalysis to 2.28 h−1 for PEC. Finally, the morphology modulation, trap doping and compositing strategies were also extensively applied in PEC to further enhance the separation of charge carriers, for example, layer stacking (morphology modulation), Fe-modification (trap doping) and ZnO compositing (compositing) could significantly improve the PEC performance compared to that of pristine titanate characterized by the increased photocurrent under illumination.
answer: photocatalysts