Abstract Nowadays, the development of composite materials has greatly stimulated people's interests to pursue a better utilization of solar light for efficient water splitting. The modulation of materials' properties for some specific purposes through manipulating external conditions has come into wide use and can provide many opportunities to promote a certain performance. In this work, we present a systematic computation study of the hybrid WS2-GeC composite that can realize a better response to solar energy and significantly strengthen the carriers' separation, achieving a higher efficiency for the water splitting reaction. A comprehensive calculation shows that the bandgap variation of WS2-GeC heterostructure exhibits an interesting response to the applied electric field compared with freestanding structures and an obvious redshift of the absorption edge is observed. The electronic structure of the interface reveals that the WS2-GeC is a typical type-II heterostructure with the photoinduced electrons/holes transfer to the conduction/valence band of WS2 from the conduction/valence band of GeC, respectively. All the above suggest that the WS2-GeC composite has significant advantages for water splitting. After the electric field applied, this heterostructure would gradually meet the standard thermodynamic requirements of a sustainable water splitting reaction for suitable band edge positions with respect to (w.r.t) the water redox levels. In brief, a convictive theoretical approach was presented to reveal the evolution of high activity for water splitting achieved by WS2-GeC heterostructures. We believe the corresponding theoretical methodology will arouse a further interest in other 2D based composite structures. This work provides a flexible and feasible approach of electric field engineering for composites applied in water splitting.

中文翻译：

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WS2-GeC异质结构的电场诱导带调制用于高效光催化水分解：密度泛函理论研究

摘要 如今，复合材料的发展极大地激发了人们追求更好地利用太阳光进行高效分解水的兴趣。通过操纵外部条件为某些特定目的调节材料的性能已得到广泛应用，并且可以提供许多机会来提升某种性能。在这项工作中，我们对混合 WS2-GeC 复合材料进行了系统的计算研究，该复合材料可以实现更好的太阳能响应并显着加强载流子的分离，实现更高的水分解反应效率。综合计算表明，与独立结构相比，WS2-GeC 异质结构的带隙变化对施加的电场表现出有趣的响应，并且观察到吸收边缘的明显红移。界面的电子结构表明 WS2-GeC 是典型的 II 型异质结构，光生电子/空穴分别从 GeC 的导带/价带转移到 WS2 的导带/价带。以上所有表明 WS2-GeC 复合材料在水分解方面具有显着优势。施加电场后，这种异质结构将逐渐满足可持续水分解反应的标准热力学要求，以针对（wrt）水氧化还原水平的合适带边缘位置。简单来说，提出了一种令人信服的理论方法来揭示 WS2-GeC 异质结构实现的高水分解活性的演变。我们相信相应的理论方法将引起人们对其他基于 2D 的复合结构的进一步兴趣。这项工作为应用于水分解的复合材料提供了一种灵活可行的电场工程方法。