探究超薄Bi_(2)MoO_(6)纳米片高效光催化CO_(2)还原活性  

Unveiling the Activity Origin of Ultrathin Bi_(2)MoO_(6) Nanosheets for Photocatalytic CO_(2) Reduction

作　　者：兰钰婕 梁卿[1] 黄晓卷[1] 毕迎普[1] 张亚军 LAN Yu-jie;LIANG Qing;HUANG Xiao-juan;BI Ying-pu;ZHANG Ya-jun(State Key Laboratory of Oxo Synthesis and Selective Oxidation,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院兰州化学物理研究所羰基合成与选择氧化国家重点实验室,甘肃兰州730000 [2]中国科学院大学,北京100049

出　　处：《分子催化（中英文）》2024年第2期121-129,I0002,共10页Journal of Molecular Catalysis(China)

基　　金：国家自然科学基金资助项目(22072168);中国科学院西部之光“西部青年学者”。

摘　　要：铋系层状半导体材料凭借其独特的表面特性在光催化领域得到广泛的研究及应用,然而在光催化反应过程中光生电荷迁移及其表界面动态变化却鲜见报道.我们利用准原位X射线光电子能谱仪(QIS-XPS)系统研究超薄Bi_(2)MoO_(6)纳米片光催化CO_(2)还原过程中光生电荷迁移及其表界面演变过程.研究结果表明:在暗态条件下CO_(2)分子吸附于(010)暴露面Bi活性位,由于CO_(2)分子强的拉电子能力,导致内层出现高价态Mo^((6+x)+).当光照射至样品表面上时,*CO_(2)特征峰强度显著降低,*CO特征峰强度明显升高,表明CO_(2)分子在Bi活性位发生活化断键,并与光生电子反应形成*CO,使得高价态Mo^((6+x)+)含量增大.活性测试表明超薄Bi2MoO6纳米片的CO产量活性为41.8μmol·g^(-1)·h^(-1),其比块体Bi_(2)MoO_(6)活性高4.2倍,并且展现出优异的光催化稳定性.该工作为二维层状材料高效光催化CO_(2)还原机理研究提供了一种全新的研究思路.Bismuth-based layer semiconductors have attracted particular attention for various photocatalytic applications,owing to their unique surface properties.However,the changes of photocharge migration and surface/interface structure during photocatalytic reactions are rarely reported.Herein,we first observe the dynamic evolution of photocharge migration and surface/interface structure over ultrathin Bi_(2)MoO_(6) nanosheets during photocatalytic CO_(2) reduction via quasi in situ X-ray photoelectron spectroscopy.Specifically,under the ground state,CO_(2) molecules adsorbed on the Bi activity site of the(010)exposed facet,owing to the strong electron-attraction of CO_(2) molecules,leading to the high-valance Mo^(6+x)+in the inner layer increase significantly.Upon light irradiation,the characterization peak of*CO_(2) significantly decreased,while the peak of*CO evidently increased,indicating that CO_(2) molecules were activated,and reacted with the photogenerated electrons to form*CO,which increased the proportion of high-valance Mo^(6+x)+species.By virtue of the above unique characteristic changes,ultrathin Bi2MoO6 nanosheets exhibit excellent CO_(2) reduction to CO activity(41.8μmol∙g^(−1)∙h^(−1)),which is nearly 4.2 times higher than that of bulk Bi_(2)MoO_(6) nanosheets.Thus,this case provides new possibilities for photocatalyst design using two-dimensional materials with high solar-driven photocatalytic activity.

关 键 词：光催化 超薄纳米片 Bi_(2)MoO_(6) CO_(2)还原 电荷迁移 

分 类 号：O643.32[理学—物理化学]