Zn-promoted redispersion of Pd/AC sintered catalyst under O2–CO atmosphere

Abstract

Sintering deactivation of loaded precious metal catalysts is a pressing issue in the field, significantly reducing catalyst activity. Among them, the redispersion of carbon-loaded precious metal catalysts under a high-temperature atmosphere suffers from the problem of carbon carriers being prone to carbonization. In this study, the sintered PdZn/AC catalysts could be redispersed at low temperatures by adding the additive Zn. Combined with TEM, XRD, XPS, and other characterization means, it was found that the main reason for the redispersion of the sintered catalysts was that the Zn additive could form an alloy with Pd, which promoted the formation of high-valent Pd species, which exfoliated into small particles by oxidation in the O₂–CO atmosphere. In addition, the factors that influenced the process (Zn content, redispersion temperature, treatment time, and number of treatments) were investigated using the controlled variable method. The present work presents a new idea for recycling sintered precious metal catalysts.