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.

Automated summary

In this study, Ru-B catalysts were designed to achieve efficient O-2 activation by enhancing the electron density around Ru. The catalysts showed low-temperature catalytic activity for the degradation of DBM, with lower energy consumption and higher catalytic activity compared to pristine Ru/TiO2. By adjusting the electron density with boron, the catalysts could activate O-2 and form reactive oxygen species, leading to fast conversion and oxidation of intermediates and boosting the catalytic activity at low temperatures.