The energy band alignment and photocatalytic performance of α-In₂Se₃/g-C₃N₄ heterojunctions of two configurations (A and B) are studied through first-principles calculations. The spontaneous out-of-plane electric polarization of α-In₂Se₃ points away from g-C₃N₄ for configuration A, in which the layer spacing and formation energy are lower than those of configuration B. Configuration A of α-In₂Se₃/g-C₃N₄ is characteristic of the I-type energy band alignment and S-scheme heterojunction for photocatalytic performance, which is different from the II-type band alignment characteristic of the previous traditional Z-scheme heterojunctions with a larger built-in electric field. The existence of a stronger intrinsic electric field of α-In₂Se₃ causes the photogenerated electrons in α-In₂Se₃ to migrate across the interface region of α-In₂Se₃/g-C₃N₄ to reach the valence band maximum (VBM) of g-C₃N₄ for configuration A. The recombination of the photogenerated electrons from the conduction band minimum (CBM) of α-In₂Se₃ with holes from the VBM of g-C₃N₄ reduces the number of photogenerated holes in the VBM of g-C₃N₄. The photogenerated electrons in the CBM of g-C₃N₄ due to the absence of holes move toward the surface of g-C₃N₄ and play a significant role in the hydrogen generation activity.

中文翻译：

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α-In2Se3/g-C3N4异质结构中I型能带排列的S-Scheme光催化机理

通过第一性原理计算研究了两种构型（A和B）的α-In ₂ Se ₃ /gC ₃ N ₄异质结的能带排列和光催化性能。对于配置A，α-In ₂ Se ₃的自发面外电极化指向远离gC ₃ N ₄的方向，其中层间距和形成能低于配置B。 α-In _{2 的}配置A Se ₃ /gC ₃ N ₄是 I 型能带排列和 S 型异质结的光催化性能特征，这与以前具有更大内置电场的传统 Z 型异质结的 II 型能带排列特性不同。α-在更强的固有电场的存在₂硒₃引起α-在光生电子₂硒₃跨越的界面区域迁移α-在₂硒₃ / GC ₃ Ñ ₄到达价带最大值(VBM) gC ₃ N ₄用于配置A.从导带最小值（CBM）α-In的光生电子的重组₂硒₃与来自GC的VBM孔₃ Ñ ₄减少GC的VBM光生空穴的数量₃ Ñ ₄。由于没有空穴，gC ₃ N ₄煤层气中的光生电子向gC ₃ N ₄表面移动，并在产氢活性中起重要作用。