Valence state and redox property of Fe‐CNTs added CeO ₂ /TiO ₂ catalyst

Abstract The investigation focused on examining the impact of incorporating Fe‐carbon nanotubes (CNTs) on the valence state and oxygen vacancies, and the physicochemical parameters of the catalytic system. For the CeO 2 /TiO 2 catalyst with Fe‐CNTs, no distinct X‐ray diffraction (XRD) peaks corresponding to Fe‐CNTs were observed. This indicated their uniform dispersion, supported by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) imaging. X‐ray photoelectron spectroscopy (XPS) analysis was conducted to observe the changes in the valence state due to the addition of Fe‐CNTs. The concentration of Ce 3+ on catalyst surface increased from 19.90% to 29.48% with an increased concentration of the chemisorbed oxygen species (O α ). This suggests that the addition of Fe‐CNTs into CeO 2 /TiO 2 catalyst reduced Ce 4+ on the catalyst surface, resulting in the formation of oxygen vacancies. Oxygen temperature‐programmed desorption (O 2 ‐TPD) and hydrogen temperature‐programmed reduction (H 2 ‐TPR) analyses showed both the adsorbed oxygen species and H 2 consumption increased with adding Fe‐CNTs. Furthermore, the onset temperatures for O 2 desorption and H 2 consumption became lower, confirming the enhancement of catalytic redox properties.