The ability to engineer a photoelectrode surface is pivotal for optimizing the properties of any photoelectrode used for solar fuel production. Altering crystal facets exposed on the surface of photoelectrodes has been a major strategy to modify their surface structure. However, there exist numerous ways to terminate the surface even for the same facet, which can considerably alter the photoelectrode properties. Here we report tightly integrated experimental and computational investigations of epitaxial BiVO₄ photoelectrodes with vanadium- and bismuth-rich (010) facets. Our study demonstrates that even for the same facet the surface Bi:V ratio has a remarkable impact on the interfacial energetics and photoelectrochemical properties. We also elucidate the microscopic origins of how the surface composition can affect the photoelectrochemical properties. This study opens an unexplored path for understanding and engineering surface energetics via tuning the surface termination/composition of multinary oxide photoelectrodes.

设计光电极表面的能力对于优化用于太阳能燃料生产的任何光电极的特性至关重要。改变暴露在光电极表面的晶面一直是改变其表面结构的主要策略。然而，即使对于相同的刻面，也存在许多终止表面的方法，这会显着改变光电极的特性。_{在这里，我们报告了外延 BiVO 4}的紧密集成的实验和计算研究具有富钒和富铋 (010) 晶面的光电极。我们的研究表明，即使对于相同的刻面，表面 Bi:V 比对界面能量学和光电化学性质也有显着影响。我们还阐明了表面成分如何影响光电化学性质的微观起源。这项研究通过调整多元氧化物光电极的表面终止/组成，为理解和设计表面能量学开辟了一条未探索的道路。