Photocatalytic materials with overall water splitting utilizing infrared light are of particular interest for clean energy applications and environmental pollution. So far, few two-dimensional (2D) material has been identified to be in this class of materials without any additional tuning. Here, we demonstrate that, under infrared spectrum, 2D In₂X₃ (X = S, Se, Te) hold great potential and advantages in overall water splitting. We reveal that In₂X₃ monolayers are polarized semiconductors with an indirect band gap, and harbor a special band characteristic that is favorable for reducing the carrier recombination. Moreover, they exhibit excellent optical absorption under visible light spectrum. Remarkably for In₂Te₃ monolayer, it can even be active under near-infrared region. For In₂X₃ bilayers, the band gaps are obviously decreased, ensuring their optical absorption in infrared light region. Different from traditional photocatalysts, the intrinsic polarization of In₂X₃ systems leads to a spontaneous built-in electric field, significantly benefiting the spatial separation of photogenerated electrons and holes and thus improving the photocatalytic efficiency.

利用红外光将水进行总水分解的光催化材料对于清洁能源应用和环境污染尤为重要。到目前为止，在没有任何其他调整的情况下，几乎没有二维（2D）材料被确定为此类材料。在这里，我们证明了在红外光谱下，2D In ₂ X ₃（X = S，Se，Te）在整体水分解方面具有巨大的潜力和优势。我们发现In ₂ X ₃单层是具有间接带隙的极化半导体，并具有有利于减少载流子复合的特殊带特征。而且，它们在可见光谱下显示出优异的光吸收。对于In ₂Te ₃单层，它甚至可以在近红外区域具有活性。对于In ₂ X ₃双层，带隙明显减小，从而确保了它们在红外光区域的光吸收。与传统的光催化剂不同，In ₂ X ₃系统的固有极化导致自发的内置电场，从而大大有利于光生电子和空穴的空间分离，从而提高了光催化效率。