The limitation of pristine BiVO₄ photoanode severely causes the high carrier recombination efficiency and low energy conversion efficiency in the photoelectrochemical (PEC) system. In this work, the Ag-Pi/BiVO₄ n-n heterojunction has been rationally designed and fabricated for efficient PEC water splitting, through successive ionic layer adsorption reaction method. The built-in field of Ag-Pi/BiVO₄ significantly promotes the separation efficiency of photogenerated carriers, benefiting for the participation of abundant holes in water oxidation. The photocurrent density of 40-Ag-Pi/BiVO₄ has been enhanced to 2.32 mA/cm², which is 4.5 times than that of the pristine BiVO₄. Compared with the pristine BiVO₄ (6.5%), the IPCE value of 40-Ag-Pi/BiVO₄ achieves 22% (410 nm, 1.23V_RHE). In addition, the charge injection efficiency (η_injection) and charge separation efficiency (η_separation) of 40-Ag-Pi/BiVO₄ have been achieved to 74.36% (1.23 V_RHE) and 31.57% (1.23 V_RHE), respectively, revealing the excellent carriers’ transfer behavior in the both bulk and interface. The desirable stability endows Ag-Pi/BiVO₄ system with a great potential in the practical application in PEC water splitting, and the corresponding mechanism for in-depth understanding the process of carriers’ transfer in Ag-Pi/BiVO₄ structure has been also proposed. Therefore, the construction of Ag-Pi/BiVO₄ heterojunction will provide a new insight for the configuration of efficient PEC system.

原始BiVO ₄光电阳极的局限性严重导致了光电化学（PEC）系统中高载流子复合效率和低能量转换效率。在这项工作中，通过连续的离子层吸附反应方法，合理设计和制造了Ag-Pi / BiVO ₄ n - n异质结，可以有效地进行PEC水分解。Ag-Pi / BiVO ₄的内置磁场显着提高了光生载流子的分离效率，有利于大量空穴参与水氧化。40-Ag-Pi / BiVO ₄的光电流密度提高到2.32 mA / cm ²，是原始BiVO的4.5倍₄。与原始BiVO ₄（6.5％）相比，40-Ag-Pi / BiVO ₄的IPCE值达到22％（410 nm，1.23V _RHE）。此外，40-Ag-Pi / BiVO ₄的电荷注入效率（η_注入）和电荷分离效率（η_分离）分别达到74.36％（1.23 V _RHE）和31.57％（1.23 V _RHE），揭示了出色的载体在散装和界面上的转移行为。理想的稳定性赋予了Ag-Pi / BiVO ₄该系统在PEC水分解中的实际应用中具有很大的潜力，并提出了相应的机制来深入理解Ag-Pi / BiVO ₄结构中载流子的转移过程。因此，Ag-Pi / BiVO ₄异质结的构建将为高效PEC系统的配置提供新的见解。