The intrinsic dipole inside two-dimensional (2D) materials is always expected to enhance solar water splitting, while atomic replacement is a widely applied approach to designing water-splitting photocatalysts. However, the relationship between solar conversion between atomic replacement is unclear. Herein, the water-splitting photocatalytic performance of derivative GaS (-GaS) monolayers including GaSSe-, GaSSe-, and GaSSe- are investigated using first-principles studies. Theoretical calculations demonstrate that -GaS monolayers can be synthesized due to structural stability, and impressively their dipole moments can be regulated by atomic replacement. They hold separated conduction band minimums (CBMs) and valence band maximums (VBMs), thus supporting hydrogen evolution reactions (HERs) and oxygen evolution reactions (OERs) in different atomic regions. They have abundant driving forces for water splitting due to large overpotentials. Because of moderate bandgaps, they absorb large amounts of visible and infrared light. Among them, GaSSe- and GaSSe- monolayers possess solar-to-hydrogen (STH) efficiency (∼18%), far exceeding the commercial standard (10%). More remarkably, we find that the intrinsic dipole is inversely related to the STH efficiency and can be purposefully regulated by atomic replacement. Thereby, this work directly correlates the STH efficiency with the atomic replacement. Finally, the HER and OER of single-layer GaSSe- can be accomplished under light irradiation.

中文翻译：

---

作为水分解光催化剂的衍生 Ga2S3 单层：增强太阳能到氢的转化以减少偶极子


二维（2D）材料内部的固有偶极子总是有望增强太阳能水分解，而原子替代是设计水分解光催化剂的一种广泛应用的方法。然而，原子替代之间的太阳能转换之间的关系尚不清楚。在此，利用第一原理研究研究了衍生 GaS (-GaS) 单层（包括 GaSSe-、GaSSe- 和 GaSSe-）的水分解光催化性能。理论计算表明，由于结构稳定性，可以合成-GaS单层，并且令人印象深刻的是，它们的偶极矩可以通过原子置换来调节。它们具有分离的导带最小值 (CBM) 和价带最大值 (VBM)，从而支持不同原子区域的析氢反应 (HER) 和析氧反应 (OER)。由于较大的超电势，它们具有丰富的水分解驱动力。由于适中的带隙，它们吸收大量的可见光和红外光。其中，GaSSe-和GaSSe-单层材料具有太阳能制氢（STH）效率（∼18%），远远超过商业标准（10%）。更值得注意的是，我们发现本征偶极子与 STH 效率成反比，并且可以通过原子替换有目的地调节。因此，这项工作将 STH 效率与原子替换直接关联起来。最后，单层GaSSe-的HER和OER可以在光照射下完成。