Liu Fangting, Chen Chengcheng, Zhang Qiaoyu, Zhang Zhengguo, Fang Xiaoming
Key Laboratory of Enhanced Heat Transfer and Energy Conservation, The Ministry of Education, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China.
Guangdong Engineering Technology Research Center of Efficient Heat Storage and Application, South China University of Technology, Guangzhou 510640, China.
Nanoscale. 2022 Aug 18;14(32):11664-11675. doi: 10.1039/d2nr02536a.
Direct Z-scheme photocatalytic systems are very promising composite photocatalysts, and their photocatalytic performance is highly associated with the quality of the interface within them. Herein, a novel direct Z-scheme heterojunction with a coherent interface has been presented for the first time. Specifically, the heterojunction was constructed by dispersing pre-prepared BiVO crystals into the reaction system to synthesize CuSnS, followed by a hydrothermal reaction. It is shown that CuSnS was deposited on the surface of each pre-prepared BiVO crystal as a thin layer heterogeneous nucleation to acquire a core-shell heterojunction. The BiVO@CuSnS heterojunction was found to possess an atomic coherent interface, which is formed through the bonding between the (121) plane of BiVO and the (112) plane of CuSnS, originating from the matching in the crystalline lattice between the two planes. The coherent interface facilitated the charge transfer from CuSnS to BiVO owing to the difference in their Fermi levels, thereby forming a built-in electric field pointing from CuSnS to BiVO. Reduced fluorescence emission and a shortened carrier lifetime reveal an obvious reduction in the inter-band charge recombination for the optimal BVO@CTS-0.19 sample. Consequently, BVO@CTS-0.19 shows remarkably enhanced photocatalytic performance in MO degradation, Cr reduction and oxygen evolution. The Z-scheme charge transfer mechanism for BVO@CTS-0.19 was verified by a suite of techniques. This work provides a universal strategy for building a coherent interface to develop high-performance direct Z-scheme heterojunctions.
直接Z型光催化体系是非常有前景的复合光催化剂，其光催化性能与体系内部界面的质量高度相关。在此，首次提出了一种具有相干界面的新型直接Z型异质结。具体而言，通过将预先制备的BiVO晶体分散到反应体系中合成CuSnS，随后进行水热反应来构建异质结。结果表明，CuSnS以薄层异质成核的形式沉积在每个预先制备的BiVO晶体表面，从而获得核壳型异质结。发现BiVO@CuSnS异质结具有原子相干界面，该界面通过BiVO的(121)面与CuSnS的(112)面之间的键合形成，源于两个平面晶格的匹配。由于费米能级的差异，相干界面促进了电荷从CuSnS向BiVO的转移，从而形成了从CuSnS指向BiVO的内建电场。荧光发射的降低和载流子寿命的缩短表明，对于最佳的BVO@CTS-0.19样品，带间电荷复合明显减少。因此，BVO@CTS-0.19在MO降解、Cr还原和析氧方面表现出显著增强的光催化性能。通过一系列技术验证了BVO@CTS-0.19的Z型电荷转移机制。这项工作为构建相干界面以开发高性能直接Z型异质结提供了一种通用策略。
