DataSheet1_Theoretical study on photocatalytic performance of ZnO/C2N heterostructure towards high efficiency water splitting.docx

The construction of van der Waals heterostructures offers effective boosting of the photocatalytic performance of two-dimensional materials. In this study, which uses the first-principles method, the electronic and absorptive properties of an emerging ZnO/C2N heterostructure are systematically explored to determine the structure’s photocatalytic potential. The results demonstrate that ZnO and C2N form a type-II band alignment heterostructure with a reduced band gap, and hence superior absorption in the visible region. Furthermore, the band edge positions of a ZnO/C2N heterostructure meet the requirements for spontaneous water splitting. The ZnO/C2N heterostructure is known to possess considerably improved carrier mobility, which is advantageous in the separation and migration of carriers. The Gibbs free energy calculation confirms the high catalytic activity of the ZnO/C2N heterostructure for water-splitting reactions. All the aforementioned properties, including band gap, band edge positions, and optical absorption, can be directly tuned using biaxial lateral strain. A suitable band gap, decent band edge positions, high catalytic activity, and superior carrier mobility thus identify a ZnO/C2N heterostructure as a prominent potential photocatalyst for water splitting.

范德瓦尔斯异质结（van der Waals heterostructures）的构建可有效提升二维材料的光催化性能。本研究采用第一性原理方法，系统探究了新型氧化锌/氮化碳（ZnO/C2N）异质结的电子与光学吸收特性，以评估该结构的光催化潜力。结果表明，氧化锌与C2N可形成带隙降低的Ⅱ型能带对齐异质结，因此在可见光区域具备更优异的光吸收能力。此外，该ZnO/C2N异质结的能带边位置满足自发水分解的要求。已知ZnO/C2N异质结拥有显著提升的载流子迁移率，这有利于载流子的分离与迁移。吉布斯自由能（Gibbs free energy）计算证实了该异质结用于水分解反应的高催化活性。上述所有特性，包括带隙、能带边位置与光学吸收特性，均可通过双轴横向应变进行直接调控。合适的带隙、适中的能带边位置、高催化活性以及优异的载流子迁移率，使ZnO/C2N异质结成为极具潜力的水分解用光催化剂。