Tailoring the surface atomic structure of materials is an efficient strategy to improve catalytic performances during deep oxidation reactions, such as autoexhaust soot oxidation. Herein, a robust catalyst of subnanometric ruthenium (Ru) clusters supported on a cubic CeO2 nanocrystal with exposed 100 facets (Ru/CeO2-C) is designed to realize high performance for soot oxidation. The heterostructure interface between Ru clusters and CeO2-100 facets induces a strong interaction that facilitates the dissociation of H2O. The Ru/CeO2-C catalyst exhibits impressive water-dependent catalytic activity and thermal stability during soot oxidation. In the presence of water vapor as a usual catalytic inhibitory poison, its value of T50 (temperature of half of soot oxidation) and TOF (turnover frequency) is 312 °C and 1. 21 h-1, respectively, and the rate of soot oxidation is 1. 38-fold of the absence of water. Comprehensive experimental and theoretical calculations analyses substantiate that the interfacial Ru&+-Ov-Ce3+ bond chain structure significantly promotes H2O dissociation and O2 activation, resulting in the generation of highly reactive oxygen species (OH*/OOH*). The generated OH*/NO2 species can attack the edge carbon atoms of soot, leading to the formation of surface oxygen complexes that act as crucial reaction intermediates. The water vapor acts as an "initiator" and can enhance the decomposition of the surface oxygen complexes through hydrolysis and decarboxylation to promote soot oxidation. This finding has significant implications for filling the knowledge gaps in the water-promoted catalytic oxidation of the autoexhaust carbon particle and designing an effective water-resistant catalyst for autoexhaust purification.
Li et al. (Tue,) studied this question.