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 (O-2) 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 O-2 activation, realizing dibromomethane (DBM) degradation T 90 at 182 C-degrees on RuB1/TiO2 (about 30 C-degrees 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 2 pi* antibonding orbital of O-2 to realize the O-2 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 O-2 activation have adaptation for pollutant removal and multiple metal availability. Our study shed light on robust O(2)activation catalyst design based on electron density adjustment by boron.