Pt_n-O_v synergistic sites on MoO_x/γ-Mo₂N heterostructure for low-temperature reverse water-gas shift reaction

In heterogeneous catalysis, the interface between active metal and support plays a key role in catalyzing various reactions. Specially, the synergistic effect between active metals and oxygen vacancies on support can greatly promote catalytic efficiency. However, the construction of high-density metal-vacancy synergistic sites on catalyst surface is very challenging. In this work, isolated Pt atoms are first deposited onto a very thin-layer of MoO₃ surface stabilized on γ-Mo₂N. Subsequently, the Pt-MoO_x/γ-Mo₂N catalyst, containing abundant Pt cluster-oxygen vacancy (Pt_n-O_v) sites, is in situ constructed. This catalyst exhibits an unmatched activity and excellent stability in the reverse water-gas shift (RWGS) reaction at low temperature (300 °C). Systematic in situ characterizations illustrate that the MoO₃ structure on the γ-Mo₂N surface can be easily reduced into MoO_x (2 < x < 3), followed by the creation of sufficient oxygen vacancies. The Pt atoms are bonded with oxygen atoms of MoO_x, and stable Pt clusters are formed. These high-density Pt_n-O_v active sites greatly promote the catalytic activity. This strategy of constructing metal-vacancy synergistic sites provides valuable insights for developing efficient supported catalysts.