Catalytically efficient Ni-NiO_x-Y₂O₃ interface for medium temperature water-gas shift reaction

The metal-support interfaces between metals and oxide supports have long been studied in catalytic applications, thanks to their significance in structural stability and efficient catalytic activity. The metal-rare earth oxide interface is particularly interesting because these early transition cations have high electrophilicity, and therefore good binding strength with Lewis basic molecules, such as H₂O. Based on this feature, here we design a highly efficient composite Ni-Y₂O₃ catalyst, which forms abundant active Ni-NiO_x-Y₂O₃ interfaces under the water-gas shift (WGS) reaction condition, achieving 140.6 μmol_CO g_cat^-1 s^-1 rate at 300 °C, which is the highest activity for Ni-based catalysts. A combination of theory and ex/in situ experimental study suggests that Y₂O₃ helps H₂O dissociation at the Ni-NiO_x-Y₂O₃ interfaces, promoting this rate limiting step in the WGS reaction. Construction of such new interfacial structure for molecules activation holds great promise in many catalytic systems.