Facet-Dependent Interfacial Charge Transfer in TiO2/Nitrogen-Doped Graphene Quantum Dots Heterojunctions for Visible-Light Driven Photocatalysis
Facet-Dependent Interfacial Charge Transfer in TiO2/Nitrogen-Doped Graphene Quantum Dots Heterojunctions for Visible-Light Driven Photocatalysis
复制标题
用于可见光驱动光催化的 TiO2/氮掺杂石墨烯量子点异质结中的面相关界面电荷转移
DOI：
10.3390/catal9040345
复制
发表时间：
2019-04-01
期刊：
影响因子：
3.9
通讯作者：
Yang, Junhe
中科院分区：
文献类型：
--
作者：
Ou, Nan-Quan;Li, Hui-Jun;Yang, Junhe
界面电荷转移是太阳能有效转化为燃料和电能的关键。为了提高光激发载流子的转移效率，本文制备了由不同比例暴露{101}和{001}面的锐钛矿型TiO2和氮掺杂量子点（NGQDs）组成的异质结复合材料。在可见光照射下，对所有样品的光催化性能进行了评价，结果表明含有56% {001}facet的TiO2杂化物的光催化活性最好。TiO2/NGQDs具有优异的光活性是由于以下因素的协同作用：(i) NGQDs独特的化学特性使其具有较高的电子导电性，并通过形成Ti-O-C化学键与TiO2表面直接接触。（ii）共暴露的{101}和{001}面有利于锐钛型TiO2中载流子的分离和转移。（iii） NGQDs与TiO2富电子{101}面之间的给受体相互作用可以显著增强光电流，从而阻碍载流子的重组速率。对其物理化学性质的广泛表征进一步表明，石墨烯量子点(GQDs)/TiO2中面控电子-空穴分离和供体-受体相互作用对光催化活性的协同作用。
Interfacial charge transfer is crucial in the efficient conversion of solar energy into fuels and electricity. In this paper, heterojunction composites were fabricated, comprised of anatase TiO2 with different percentages of exposed {101} and {001} facets and nitrogen-doped quantum dots (NGQDs) to enhance the transfer efficiency of photo-excited charge carriers. The photocatalytic performances of all samples were evaluated for RhB degradation under visible light irradiation, and the hybrid containing TiO2 with 56% {001} facets demonstrated the best photocatalytic activity. The excellent photoactivity of TiO2/NGQDs was owed to the synergistic effects of the following factors: (i) The unique chemical features of NGQDs endowed NGQDs with high electronic conductivities and provided its direct contact with the TiO2 surface via forming Ti–O–C chemical bonds. (ii) The co-exposed {101} and {001} facets were beneficial for the separation and transfer of charge carriers in anatase TiO2. (iii) The donor-acceptor interaction between NGQDs and electron-rich {101} facets of TiO2 could remarkably enhance the photocurrent, thus hindering the charge carriers recombination rate. Extensive characterization of their physiochemical properties further showed the synergistic effect of facet-manipulated electron-hole separation in TiO2 and donor-acceptor interaction in graphene quantum dots (GQDs)/TiO2 on photocatalytic activity.