标题： 设计二维八原子层 M$_2$A$_2$Z$_4$作为有前途的全水分解光催化剂 显示英文标题

标题： Designing Two-Dimensional Octuple-Atomic-Layer M$_2$A$_2$Z$_4$ as Promising Photocatalysts for Overall Water Splitting

摘要： 二维（2D）材料由于其大的比表面积和可调的电子性质，已成为有前景的光催化材料候选者。 在本工作中，我们使用第一性原理计算系统地设计和筛选了一系列八原子层M$_2$A$_2$Z$_4$单层材料（M = Al，Ga，In；A = Si，Ge，Sn；Z = N，P，As）。 通过插层方法构建了108种结构，随后对其热力学和动力学稳定性、带隙以及导带和价带排列进行了全面评估，以评估它们在光催化全水分解中的潜力。 其中，八个候选材料满足在酸性条件（pH = 0）下整体水分解的条件，Al$_2$Si$_2$N$_4$和 Al$_2$Ge$_2$N$_4$进一步在酸性和中性环境（pH = 0 和 7）下表现出适合光催化的带边位置。 Al$_2$Si$_2$N$_4$和 Al$_2$Ge$_2$N$_4$在水溶液条件下也表现出明显的可见光吸收和结构稳定性。 重要的是，在Al$_2$Si$_2$N$_4$和 Al$_2$Ge$_2$N$_4$表面引入N空位显著增强了它们在氢气还原和水分解反应中的催化活性，进一步支持了它们作为整体水分解光催化剂的潜力。 我们的研究为高效稳定二维光催化剂的整体水分解设计提供了理论见解。 显示英文摘要

摘要： Two-dimensional (2D) materials have emerged as promising candidates as photocatalytic materials due to their large surface areas and tunable electronic properties. In this work, we systematically design and screen a series of octuple-atomic-layer M$_2$A$_2$Z$_4$ monolayers (M = Al, Ga, In; A = Si, Ge, Sn; Z = N, P, As) using first-principles calculations. 108 structures are constructed by intercalation approach, followed by a comprehensive evaluation of their thermodynamic and dynamic stability, band gaps, and band edge alignments to assess their potential for photocatalytic overall water splitting. Among them, eight candidates meet the criteria for overall water splitting under acidic condition (pH = 0), and Al$_2$Si$_2$N$_4$ and Al$_2$Ge$_2$N$_4$, further exhibit suitable band edge positions for photocatalysis under both acidic and neutral environments (pH = 0 and 7). Al$_2$Si$_2$N$_4$ and Al$_2$Ge$_2$N$_4$ also show pronounced visible-light absorption and structural stability in aqueous conditions. Importantly, the introduction of N vacancies on the surfaces of Al$_2$Si$_2$N$_4$ and Al$_2$Ge$_2$N$_4$ significantly enhances their catalytic activity for both hydrogen reduction and water oxidation reactions, further supporting their potential as photocatalysts for overall water splitting. Our study provides theoretical insights for the rational design of efficient and stable 2D photocatalysts for overall water splitting.