Electron Donation from Boron Suboxides via Strong p–d Orbital Hybridization Boosts Molecular O2 Activation on Ru/TiO2 for Low-Temperature Dibromomethane Oxidation

Low-temperature catalytic oxidation is of significance to the degradation of halogenated volatile organic compounds (HVOCs) to avoid hazardous byproducts with low energy consumption. Efficient molecular oxygen (O2) activation is pivotal to it but usually limited by the insufficient electron cloud de...

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Bibliographic Details
Published in:Environmental science & technology 2023-11, Vol.57 (45), p.17566-17576
Main Authors: Gao, Guanqun, Liu, Wei, Liu, Zhisong, Li, Zihao, Xu, Haomiao, Huang, Wenjun, Yan, Naiqiang, Qu, Zan
Format: Article
Language:English
Subjects:
Boron
Catalysts
Catalytic activity
Catalytic oxidation
Degradation
Electron clouds
Electron density
Electron transfer
Energy consumption
Hybridization
Intermediates
Low temperature
Organic compounds
Oxidation
Oxygen
Oxygen consumption
Physico-Chemical Treatment and Resource Recovery
Pollutant removal
Reactive oxygen species
Titanium dioxide
VOCs
Volatile organic compounds
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Summary:Low-temperature catalytic oxidation is of significance to the degradation of halogenated volatile organic compounds (HVOCs) to avoid hazardous byproducts with low energy consumption. Efficient molecular oxygen (O2) activation is pivotal to it but usually limited by the insufficient electron cloud density at the metal center. Herein, Ru–B catalysts with enhanced electron density around Ru were designed to achieve efficient O2 activation, realizing dibromomethane (DBM) degradation T 90 at 182 °C on RuB1/TiO2 (about 30 °C lower than pristine Ru/TiO2) with a TOFRu value of 0.055 s–1 (over 8 times that of Ru/TiO2). Compared to the limited electron transfer (0.02 e) on pristine Ru/TiO2, the Ru center gained sufficient negative charges (0.31 e) from BO x via strong p–d orbital hybridization. The Ru–B site then acted as the electron donor complexing with the 2π* antibonding orbital of O2 to realize the O2 dissociative activation. The reactive oxygen species formed thereby could initiate a fast conversion and oxidation of formate intermediates, thus eventually boosting the low-temperature catalytic activity. Furthermore, we found that the Ru–B sites for O2 activation have adaptation for pollutant removal and multiple metal availability. Our study shed light on robust O2 activation catalyst design based on electron density adjustment by boron.
ISSN:0013-936X
1520-5851
DOI:10.1021/acs.est.3c04725