Probing reaction pathways for H_(2)O-mediated HCHO photooxidation at room temperature  

作　　者：Weiwei Shao Xiaodong Li Xiaolong Zu Liang Liang Yang Pan Junfa Zhu Chengming Wang Yongfu Sun Yi Xie 

机构地区：[1]Hefei National Laboratory for Physical Sciences at Microscale,National Synchrotron Radiation Laboratory,Hefei Science Center of CAS,University of Science and Technology of China,Hefei,230026,China [2]Institute of Energy,Hefei Comprehensive National Science Center,Hefei,230031,China

出　　处：《Nano Research》2021年第5期1471-1478,共8页纳米研究（英文版）

基　　金：This work was financially supported by National Key R&D Program of China(Nos.2019YFA0210004 and 2017YFA0207301);the National Natural Science Foundation of China(Nos.21975242 and 21890754);the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000);Youth Innovation Promotion Association of CAS(No.CX2340007003);Major Program of Development Foundation of Hefei Center for Physical Science and Technology(No.2020HSC-CIP003);Key Research Program of Frontier Sciences of CAS(No.QYZDYSSW-SLH011);the Fok Ying-Tong Education Foundation(No.161012);Supercomputing USTC and National Supercomputing Center in Shenzhen are acknowledged for computational support.

摘　　要：Photooxidation provides a promising strategy for removing the dominant indoor pollutant of HCHO,while the underlying photooxidation mechanism is still unclear,especially the exact role of H2O molecules.Herein,we utilize in-situ spectral techniques to unveil the H2O-mediated HCHO photooxidation mechanism.As an example,the synthetic defective Bi2WO6 ultrathin sheets realize high-rate HCHO photooxidation with the assistance of H2O at room temperature.In-situ electron paramagnetic resonance spectroscopy demonstrates the existence of•OH radicals,possibly stemmed from H2O oxidation by the photoexcited holes.Synchrotron-radiation vacuum ultraviolet photoionization mass spectroscopy and H218O isotope-labeling experiment directly evidence the formed•OH radicals as the source of oxygen atoms,trigger HCHO photooxidation to produce CO2,while in-situ Fourier transform infrared spectroscopy discloses the HCOO*radical is the main photooxidation intermediate.Density-functional-theory calculations further reveal the•OH formation process is the rate-limiting step,strongly verifying the critical role of H2O in promoting HCHO photooxidation.This work first clearly uncovers the H2O-mediated HCHO photooxidation mechanism,holding promise for high-efficiency indoor HCHO removal at ambient conditions.

关 键 词：mechanistic study H_(2)O-mediated HCHO photooxidation room temperature 

分 类 号：O64[理学—物理化学]