Single-Layer Group-III Monochalcogenide Photocatalysts for Water Splitting
Single-Layer Group-III Monochalcogenide Photocatalysts for Water Splitting
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DOI：
10.1021/cm401661x
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发表时间：
2013-08-13
影响因子：
8.6
通讯作者：
Hennig, Richard G.
中科院分区：
文献类型：
--
作者：
Zhuang, Houlong L.;Hennig, Richard G.
最近的单层GaS和GaSe的合成打开了其他单层III族单硫族化物（MX，M = Ga和In，X = S，Se和Te）的稳定性问题，以及尺寸减小如何影响这些材料的性能。使用第一性原理设计方法，我们确定，单层III族单硫族化合物具有低的形成能，适合于光催化水裂解。首先，密度泛函计算使用货车的德瓦尔斯功能揭示的monocalcogenides具有类似的单层二硫化钼的形成能，这意味着容易机械提取单层monocalcogenides从他们的分层散装对应。接下来，使用混合密度泛函和准粒子多体G（0）W（0）近似计算确定导带和价带边缘位置。比较带边位置与水的氧化还原电位表明，单层单硫族化合物是潜在的水裂解的光催化剂。此外，可以通过双轴应变来调节单层单硫族化物的带隙、带边位置和光吸收，以提高太阳能转换效率。最后，单层单硫族化合物的溶剂化焓的计算表明它们在水溶液中的稳定性。
The recent synthesis of single-layer GaS and GaSe opens the question of stability for other single-layer group-III monochalcogenides (MX, M = Ga and In, X = S, Se, and Te) and how the dimension reduction affects the properties of these materials. Using a first-principles design approach, we determine that the single-layer group-III monochalcogenides exhibit low formation energies and are suitable for photocatalytic water splitting. First, density-functional calculations using a van der Waals functional reveal that the monochalcogenides have formation energies similar to that of single-layer MoS2, implying the ease of mechanically extracting single-layer monochalcogenides from their layered bulk counterparts. Next, calculations using a hybrid density functional and the quasiparticle many-body G(0)W(0) approximation determine the conduction and valence band edge positions. Comparing the band edge positions with the redox potentials of water shows that single-layer monochalcogenides are potential photocatalysts for water splitting. Moreover, the bandgaps, band edge positions, and optical absorption of the single-layer monochalcogenides can be tuned by biaxial strain to increase the efficiency of solar energy conversion. Finally, calculations of the enthalpy of solvation of the single-layer monochalcogenides suggest their stability in aqueous solution.