Mesostructured Co–Ce–Zr–Mn–O composite as a potential catalyst for efficient removal of carbon monoxide from hydrogen-rich stream

Abstract

Mesostructured Co_xCe_0.85Zr_0.15Mn_yO_ε composites were firstly prepared by a simple one-pot surfactant-assisted co-precipitation (SACP) method and then employed to catalyze the CO preferential oxidation (CO PROX) reaction in an H₂-rich stream. Effects of the Co and Mn contents (x and y, respectively) in the formula, as well as the presence of H₂O and CO₂ in feed were investigated. The as-synthesized Co_0.4Ce_0.85Zr_0.15Mn_0.10O_ε catalyst showed excellent catalytic performance in the CO PROX reaction: 100% CO conversion could be observed in a wide temperature range of 140–200 °C; even in the simulated syngas, the almost complete CO removal could still be achieved at 175–225 °C; no obvious change in both CO conversion and CO₂ selectivity over the catalyst took place during the CO PROX process with simulated syngas as feed. N₂ physisorption (BET), temperature-programmed reduction (TPR), X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopic (XPS) characterization techniques were employed to reveal the relationship between the catalyst nature and catalytic performance. The outstanding catalytic performance in CO PROX reaction was remarkably dependent on a larger specific surface area, more reducible Co³⁺ and the high dispersity of the Co₃O₄, affected by the Co and Mn contents through strong Co–Ce–Zr–Mn interactions. The mesostructured Co_0.4Ce_0.85Zr_0.15Mn_0.10O_ε catalyst prepared by the simple one-pot SACP protocol can be a promising candidate for CO PROX reaction in excess H₂.