Boron-doped graphene-based nanoflower-catalyst promoting low temperature NH₃-SCR performance: An interesting site

A series of boron-doped graphene-supported nanoflower-catalysts (nf-MnO_x/BG) were synthesized using an in-situ method to boost intrinsic catalytic performance. The regulation of catalyst structure, morphology, and active sites was systematically researched to explore the promoting factors of catalytic activity. The prepared nf-MnO_x/BG-3 catalyst achieves superior NH₃-SCR performance throughout the test process (≥90% NO_x conversion at the temperature ranging from 140 to 280 °C), comparable to the current mainstream graphene-based catalyst. The ratios of O_α/(O_α + O_β) and Mn⁴⁺/Mn³⁺are effectively increased by boron atom doping, which is strongly associated with excellent catalytic deNO_x efficiency. Meanwhile, the boron sites with unpaired electronic structures accelerate the reaction of fast-SCR by promoting oxidation and adsorption of nitrogen oxide species. Interestingly, the boron sites can be used as an additional Lewis acid and adsorbed NO₂ site to participate in the low-temperature SCR reaction and effectively improve the low-temperature activity.