FeOx supported single‐atom Pd bifunctional catalyst for water gas shift reaction

Water gas shift reaction on supported noble metal catalysts is an essential process for upgrading hydrogen source industrially. Here a series of Pd/FeO x catalysts were detected for this reaction with Pd/Al 2 O 3 as reference. It was found that Pd/FeO x exhibited higher CO conversion than Pd/Al 2 O 3 with a good stability even in the presence of CO 2 and H 2 . Along the loading decreasing, the turnover frequency of exposed Pd atoms increased with the dispersion from subnanometer (∼1 nm) to single atoms. Various characterizations suggested that Pd single atoms greatly enhanced the reducibility of FeO x and facilitated the formation of oxygen vacancies, which served as sites to promote the dissociation of H 2 O to form H 2 and atomic O. The atomic O was ready to react with the linear adsorbed CO species on Pd single‐atom sites through a redox mechanism, which resulted in low activation energy of ∼30 kJ mol −1 .