Modeling the temperature-programmed reduction of metal oxide catalysts by considering the particle-size distribution effect.

[Display omitted] • Modelling of H 2 -TPR patterns considering the effect of particle size distribution. • Three pure metal oxides were used to selecte the kinetic reaction models. • Three reaction kinetic models were considered. • Information of the metal oxide is derived from the Prout and Tompkins model. Hydrogen temperature-programmed reduction (H 2 -TPR) has become a very useful and common technique for the chemical characterization of solids as it is sensitive to the study of reducible species in catalysis and is considered to be a fingerprint for the reducibility of metal oxide catalysts. However, although modeling of H 2 -TPR patterns has been extensively studied, little attention has been paid to the effect of particle-size distribution (PSD). The complexity of modeling H 2 -TPR patterns arises from the fact that the chemistry of metal oxide reduction depends on several factors, including particle size, nature of the support material and confinement within the porous structure, amongst others. In order to identify the kinetic reaction model governing the reduction of certain metal oxides and to explore the effect of PSD, pure metal oxides that only exhibited the particle size difference effect were used to model the H 2 -TPR patterns. Kinetic and thermodynamic data, which are very useful for characterizing heterogeneous catalysts, were obtained from this study. This work presents a simple procedure for modeling H 2 -TPR patterns of various metal oxides (i.e., CuO, Ag 2 O, and NiO) used as active phases in several reactions of environmental and energetic interest using several solid-state reaction kinetic models and considering their PSDs. The results obtained show that modeling the H 2 -TPR profiles provides information regarding the PSD of metal oxide catalysts that undergo a single-step reduction and only present the particle size difference effect. [ABSTRACT FROM AUTHOR]