Establishing Donor‐Acceptor Channel on BiVO4 Photoanode via Conjugated Polytrianiline Framework Enables Efficient Photoelectrochemical Water Splitting

Abstract The establishment of charge transfer channels on BiVO 4 photoanodes is a feasible strategy to achieve effective hole extraction and improve photoelectrochemical performance. Here, a conjugated polytrianiline framework (CPF‐TTPATA) is proposed as a hole transport layer between the NiFeOx catalyst and the Mo:BiVO 4 light absorber to improve the charge separation efficiency. The CPF‐TTPATA features an acceptor triazine moiety linked by a donor triphenylamine moiety to accelerate the delocalization of photogenerated charges and possesses suitable band alignment with Mo:BiVO 4 to form a staggered type‐II heterojunction that facilitates hole extraction. Meanwhile, CPF‐TTPATA passivates the surface trap states of Mo:BiVO 4 , which promotes the interfacial charge transfer between Mo:BiVO 4 and CPF‐TTPATA. Therefore, the effective separation of photogenerated charge in our carefully designed Bi 3+ ‐acceptor‐donor‐catalyst conductive channel can be realized. The as‐prepared NiFeOx/CPF‐TTPATA/Mo:BiVO 4 photoanode exhibits an extremely high photocurrent density of 6.94 mA cm −2 and charge separation efficiency (≈100%) at 1.23 V (vs. RHE) under simulated AM 1.5G sunlight (100 mW cm −2 ). This work provides new insights for the design of organic and inorganic hybrid photoanodes for high‐performance solar water splitting applications.