Li Ang, Liu Yuxiang, Xu Xuejun, Zhang Yuanyuan, Si Zhichun, Wu Xiaodong, Ran Rui, Weng Duan
Tsinghua Shenzhen International Graduate School, Tsinghua University Shenzhen City 518055 China
College of Materials Science and Energy Engineering, Foshan University Foshan City 528000 China.
RSC Adv. 2020 May 1;10(29):17154-17162. doi: 10.1039/d0ra02083d. eCollection 2020 Apr 29.
Constructing Z-scheme heterojunctions is considered as an effective strategy to obtain catalysts of high efficiency in electron-hole separation in photocatalysis. Unfortunately, suitable heterojunctions are difficult to fabricate because the direct interaction between two semiconductors may lead to unpredictable negative effects such as electron scattering or electron trapping due to the existence of defects which causes the formation of new substances. Furthermore, the van der Waals contact between two semiconductors also results in bad electron diffusion. In this work, a MOF-derived carbon material as a Z-scheme photocatalyst was synthesized one-step thermal treatment of MoS dots @Fe-MOF (MIL-101). Under visible light irradiation, the well-constructed Z-scheme (MoS, γ-FeO)/graphene photocatalyst shows 2-fold photocatalytic oxygen evolution activity (4400 μmol g h) compared to that of γ-FeO/graphene (2053 μmol g h). Based on ultraviolet photoelectron spectrometry (UPS), Mott-Schottky plot, photocurrent and photoluminescence spectroscopy (PL) results, the photo-induced electrons from the conduction band of γ-FeO could transport quickly to the valence band of MoS highly conductive graphene as an electron transport channel, which could significantly enhance the electron-hole separation efficiency as well as photocatalytic performance.
构建Z型异质结被认为是在光催化中获得具有高效电子-空穴分离能力催化剂的有效策略。不幸的是，合适的异质结难以制备，因为两种半导体之间的直接相互作用可能会导致不可预测的负面影响，例如由于缺陷的存在导致电子散射或电子捕获，进而形成新物质。此外，两种半导体之间的范德华接触也会导致电子扩散不良。在这项工作中，通过对MoS点@Fe-MOF（MIL-101）进行一步热处理，合成了一种作为Z型光催化剂的MOF衍生碳材料。在可见光照射下，构建良好的Z型（MoS，γ-FeO）/石墨烯光催化剂的光催化析氧活性是γ-FeO/石墨烯（2053 μmol g h）的2倍（4400 μmol g h）。基于紫外光电子能谱（UPS）、莫特-肖特基曲线、光电流和光致发光光谱（PL）结果，来自γ-FeO导带的光生电子可以通过高导电性的石墨烯作为电子传输通道快速传输到MoS的价带，这可以显著提高电子-空穴分离效率以及光催化性能。
