Photocatalysts with exposure of different crystal facets often show great differences in their photocatalytic activities due to differences in surface atomic arrangement and coordination.Thus,the actual photoreac-tion mechanism of a specific crystal facet in photocatalysis deserves to be explored.In this paper,as a case study,SrBi2Ta2O9 photocatalyst with preferential facet exposure was explored for the photocatalytic removal of NO at a ppb level.The efficiency of NO removal was remarkably improved by tuning the crys-tal exposure facet with high(2 0 0)facet exposure ratio.Optimized exposure of(2 0 0)crystal facet in SrBi2Ta2O9(SBT)by thermal calcination at 800℃(SBT-800)leads to the highest NO removal activity of 51％under a 300 W Xe lamp for 20 min;under visible light,SBT 800 achieves a 5-fold enhancement in NO removal efficiency compared to its counterpart,SBT-900.Active species capture experiments prove that the superoxide radical·O2-is the main active species for the photocatalytic removal of NO,and sur-face selective deposition experiments conclude that(2 0 0)is the main electron-rich crystal plane,based on which the results of density functional theory(DFT)computation reveal the BiO terminated nature of(0 0 1)crystal plane,where the models with both BiO and Tao terminated(0 0 1)planes were created and computated.Mechanistic study reveals that SrBi2Ta2O9 with a larger exposure of(2 0 0)facet pro-vides more active reduction sites,thereby reducing more O2 to·O2-,which further oxidizes the adsorbed NO to NO2-/NO3-.The present work underlines the role of facet tuning in the photoactivity modulation for NO removal photocatalytically.

Nan Li;Qiuhui Zhu;Guimei Liu;Qi Zhao;Haiqin Lv;Mingzhe Yuan;Qingguo Meng;Yingtang Zhou;Jingkun Xu;Chuanyi Wang

School of Environmental Science and Engineering,Shaanxi University of Science and Technology,Xi'an 710021,China;Guangzhou Institute of Industrial Intelligence(GⅢ),Guangzhou 511400,China;National Engineering Research Center for Marine Aquaculture,Marine Science and Technology College,Zhejiang Ocean University,Zhoushan 316004,China;Flexible Electronics Innovation Institute(FEII),Jiangxi Science&Technology Normal University,Nanchang 330006,China

材料科学技术（英文版）

[1]Nan Li;Qiuhui Zhu;Guimei Liu;Qi Zhao;Haiqin Lv;Mingzhe Yuan;Qingguo Meng;Yingtang Zhou;Jingkun Xu;Chuanyi Wang-.Modulation of photocatalytic activity of SrBi2Ta2O9 nanosheets in NO removal by tuning facets exposure)[J].材料科学技术（英文版）,2022(27):91-100

SrBi2Ta2O9,photoreac,computated,photocatalytically

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