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

Abstract

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 . © 2017 American Institute of Chemical Engineers AIChE J , 63: 4022–4031, 2017