Theoretical and experimental investigations on single-atom catalysis: Pt1/FeOx for water–gas shift reaction
Shan-Fei Wang, Yangyang Li, Haiyan Wang, Jinxia Liang, Chun Zhu, Botao Qiao
Abstract
Oxide-supported metal single-atom catalysts (SACs) have exhibited excellent catalytic performance for water–gas shift (WGS) reaction. Here, we report the single-atom catalyst Pt 1 /FeO x exhibits excellent medium temperature catalytic performance for WGS reactions by the density functional theory (DFT) calculations and experimental results. The calculations indicate that H 2 O molecules are easily dissociated at oxygen vacancies, and the formed ⋆ OH and ⋆ O are adsorbed on Pt 1 single atoms and the adjacent O atoms, respectively. After studying four possible reaction mechanisms, it is found that the optimal WGS reaction pathway is proceeded along the carboxyl mechanism (pathway III), in which the formation of ⋆ COOH intermediates can promote the stability of Pt 1 /FeO x SAC and the easier occurrence of WGS reaction. The energy barrier of the rate-determining step during the entire reaction cycle is only 1.16 eV, showing the high activity for the medium temperature WGS reaction on Pt 1 /FeO x SAC, which was verified by experimental results. Moreover, the calculated turnover frequencies (TOFs) of CO 2 and H 2 formation on Pt 1 /FeO x at 610 K (337 °C) can reach up to 1.14 × 10 −3 s −1 ·site −1 through carboxyl mechanism. In this work, we further expand the application potential of Pt 1 /FeO x SAC in WGS reaction.