@article{Shao2021, 
author = {Weiwei Shao and Xiaodong Li and Xiaolong Zu and Liang Liang and Yang Pan and Junfa Zhu and Chengming Wang and Yongfu Sun and Yi Xie},
title = {Probing reaction pathways for H2O-mediated HCHO photooxidation at room temperature},
year = {2021},
journal = {Nano Research},
volume = {14},
number = {5},
pages = {1471-1478},
keywords = {room temperature, mechanistic study, H2O-mediated, HCHO photooxidation},
url = {https://www.sciopen.com/article/10.1007/s12274-020-3205-y},
doi = {10.1007/s12274-020-3205-y},
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 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.}
}