Photo‐driven Oxygen Vacancies Extends Charge Carrier Lifetime for Efficient Solar Water Splitting

A photocharge/discharge strategy is proposed to initiate the WO3 photoelectrode and suppress the main charge recombination, which remarkably improves the photoelectrochemical (PEC) performance. The photocharged WO3 surrounded by a 8–10 nm overlayer and oxygen vacancies could be operated more than 25 cycles with 50 h durability without significant decay on PEC activity. A photocharged WO3/CuO photoanode exhibits an outstanding photocurrent of 3.2 mA cm−2 at 1.23 VRHE with a low onset potential of 0.6 VRHE, which is one of the best performances of p‐n heterojunction structure. Using nonadiabatic molecular dynamics combined with time‐domain DFT, we clarify the prolonged charge carrier lifetime of photocharged WO3, as well as how electronic systems of photocharged WO3/CuO semiconductors enable the effective photoinduced electrons transfer from WO3 into CuO. This work provides a feasible route to address excessive defects existed in photoelectrodes without causing extra recombination. A photocharging/discharging strategy is used to initiate the WO3 electrode and prolong charge carrier lifetime for the oxygen evolution reaction. A WO3/CuO photoanode exhibited an outstanding photocurrent with a low onset potential. The prolonged charge carrier lifetime of photocharged WO3 and the electronic systems of photocharged WO3/CuO semiconductors were clarified using the nonadiabatic molecular dynamics combined with time‐domain DFT.