Cooperation of oxygen vacancies and 2D ultrathin structure promoting CO2 photoreduction performance of Bi4Ti3O12  

氧空位和超薄结构共同助力Bi4Ti3O12纳米片高效CO2光还原

作　　者：Lizhen Liu Hongwei Huang Fang Chen Hongjian Yu Na Tian Yihe Zhang Tierui Zhang 刘丽珍;黄洪伟;陈芳;于洪鉴;田娜;张以河;张铁锐(Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes,National Laboratory of Mineral Materials,School of Materials Science and Technology,China University of Geosciences,Beijing 100083,China;Key Laboratory of Photochemical Conversion and Optoelectronic Materials,Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,Beijing 100190,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes,National Laboratory of Mineral Materials,School of Materials Science and Technology,China University of Geosciences,Beijing 100083,China [2]Key Laboratory of Photochemical Conversion and Optoelectronic Materials,Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,Beijing 100190,China [3]Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science Bulletin》2020年第11期934-943,M0004,共11页科学通报（英文版）

基　　金：This work was jointly supported by the National Natural Science Foundation of China(51972288 and 51672258);the Fundamental Research Funds for the Central Universities(2652018290).

摘　　要：Reduction of CO2to solar fuels by artificial photosynthesis technology has attracted considerable attention. However, insufficient separation of charge carriers and weak CO2adsorption hamper the photocatalytic CO2 reduction activity. Herein, we tackle these challenges by introducing oxygen vacancies (OVs) on the two-dimensional Bi4Ti3O12ultrathin nanosheets via a combined hydrothermal and postreduction process. Selective photodeposition experiment of Pt over Bi4Ti3O12discloses that the ultrathin structure shortens the migration distance of photo-induced electrons from bulk to the surface, benefiting the fast participation in the CO2reduction reaction. The introduction of OVs on ultrathin Bi4Ti3O12 nanosheets leads to enormous amelioration on surface state and electronic structure, thereby resulting in enhanced CO2adsorption, photoabsorption and charge separation efficiency. The photocatalytic experiments uncover that ultrathin Bi4Ti3O12nanosheets with OVs reveal a largely enhanced CO2photoreduction activity for producing CO with a rate of 11.7 lmol g-1h-1in the gas–solid system, 3.2 times higher than that of bulk Bi4Ti3O12. This work not only yields efficient ultrathin photocatalysts with OVs, but also furthers our understanding on enhancing CO2reduction via cooperative tactics.低的电荷分离效率以及欠丰富的表面活性位点一直是阻碍高效光催化CO2还原的关键问题.针对这些问题,本文首先利用导向剂辅助的水热反应制备了Bi4Ti3O12薄层纳米片,又利用二次水热还原在其表面引入氧空位,实现了气固体系中高效光催化CO2还原,产率(11.7μmol g-1h-1)约是未改性Bi4Ti3O12的3.2倍.选择性光沉积Pt实验表明超薄结构缩短了光生电子的迁移距离,有利于其快速参与CO2还原反应.氧空位极大地改善了超薄纳米片的表面态和电子结构,大幅促进了对CO2的吸附、可见光的吸收和电荷分离.这项工作不仅报道了富含氧空位的超薄光催化材料,而且有望为发展耦合策略共同提高光催化CO2还原性能提供新见解和新思路.

关 键 词：CO2 photoreduction Oxygen vacancies Ultrathin nanosheets Charge separation Bismuth titanate 

分 类 号：TB383.1[一般工业技术—材料科学与工程]