Authors: Yuqiong Deng, Xionghui Fu, Yuanming Zhang, Yi Zhu, Yongge Wei
Published: 2022-06-16
Source: Full article
AbstractThe rate‐determining step of the oxygen evolution reaction based on a semiconductor photoanode is the formation of the OO bond. Herein, polyethylene glycol (PEG)‐modified BiVO4 photoanodes are reported, in which protons can be transferred quickly due to the high proton conductivity of PEG, resulting in the acceleration of the OO bond formation rate. These are fully demonstrated by different kinetic isotope effect values. Moreover, the open‐circuit voltage (Uoc) further illustrates that PEG passivates the surface states and surface charge recombination is reduced. The composite photoanode can achieve a maximum photocurrent density of 3.64 mA cm−2 at 1.23 V compared to 1.04 mA cm−2 for pure BiVO4, and an onset potential of 170 mV, which is a 230 mV negative shift compared to pure BiVO4. This work provides a new strategy to accelerate water oxidation kinetics for photoanodes by speeding up the transfer of the proton and the OO bond formation rate.