Manipulating Covalency to Activate Dual‐Interface Kinetics for Efficient Solar Water Splitting

ABSTRACT Interface engineering plays a crucial role in improving the performance of semiconductor‐based solar energy devices. Nevertheless, conventional interface modulation strategies still suffer from limited charge separation efficiency and sluggish surface reaction kinetics, restricting further performance improvement. Distinct from traditional interface regulation, we herein propose a novel covalency manipulation strategy to construct a dual‐interface kinetics‐activated BiVO 4 /CoPi‐F/FeOOH photoanode for efficient photoelectrochemical (PEC) water splitting. The optimized photoanode reaches a high photocurrent density of 6.72 mA/cm 2 at 1.23 V vs. RHE and exhibits remarkable stability during 24 h of continuous operation. Density functional theory (DFT) calculations combined with in situ experimental analysis reveal that the introduced CoPi‐F modulates the hole transfer pathways and promotes the separation of photogenerated charge carriers by forming electron‐rich species. At the CoPi‐F/FeOOH interface, the strengthened adsorption of oxygen‐containing intermediates facilitates surface reaction kinetics. Moreover, this universal covalency modulation strategy can be adapted to other configurations such as BiVO 4 /CoPi‐F/NiOOH for prominent PEC performance enhancement. This work demonstrates the distinct superiority of the proposed covalency manipulation strategy over existing methods, providing a useful guideline for the rational design of covalency‐tuned photoanodes and advancing the development of efficient solar‐driven water splitting technologies.