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Nano Research

Article Title

Probing reaction pathways for H2O2-mediated HCHO photooxidation at room temperature

Authors

Weiwei Shao, 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;Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China
Xiaodong Li, 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;Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China
Xiaolong Zu, 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;Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China
Liang Liang, 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;Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China
Yang Pan, 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;Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China
Junfa Zhu, 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;Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China
Chengming Wang, 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;Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China
Yongfu Sun, 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;Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China
Yi Xie, 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;Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China

Keywords

mechanistic study, H2O-mediated, HCHO photooxidation, room temperature

Abstract

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 H2O2 molecules. Herein, we utilize in-situ spectral techniques to unveil the H2O2-mediated HCHO photooxidation mechanism. As an example, the synthetic defective Bi2WO6 ultrathin sheets realize high-rate HCHO photooxidation with the assistance of H2O2 at room temperature. In-situ electron paramagnetic resonance spectroscopy demonstrates the existence of •OH radicals, possibly stemmed from H2O2 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 H2O2 in promoting HCHO photooxidation. This work first clearly uncovers the H2O2-mediated HCHO photooxidation mechanism, holding promise for high-efficiency indoor HCHO removal at ambient conditions.

Publisher

Tsinghua University Press

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