Search

[Display omitted] • Manipulating metal-support interactions in Ni/CZA catalysts were investigated. • 20Ni/40CZA contained highly dispersed Ni nanoparticles and abundant oxygen vacancies. • 20Ni/40CZA exhibited the highest H 2 production rate and the lowest coke formation. • Coke precursor gasification was promoted by the efficient delivery of active oxygen. Understanding coke formation routes over Ni-based catalysts is essential in determining the catalytic performance in ethanol steam reforming. In this study, we focused on optimizing the active sites distribution via the metal-support interactions and understanding the coke precursor gasification in Ni/Ce x Zr 1-x O 2 –Al 2 O 3 (CZA) catalysts for ethanol steam reforming. We found that the optimized active sites distribution could minimize coke formation by enabling efficient gasification of a coke precursor on Ni. In the 20Ni/40CZA catalyst, the crystalline CZ exhibited a strong interaction with Ni, maintaining a uniform distribution of highly dispersed Ni nanoparticles and creating abundant oxygen vacancies on CZ, even at 20 wt% of Ni loading. Consequently, the resistance to coking over 20Ni/40CZA was significantly enhanced due to the efficient delivery of active oxygen atoms from steam on the abundant oxygen vacancies to the coke precursor on the Ni surface, resulting in fast gasification of the coke precursor. [ABSTRACT FROM AUTHOR]

In this study, we investigated the metal–support interactions over Ni/CeO 2 –ZrO 2 (Ni/CZ) catalysts for ethanol steam reforming. Different Ni contents (5, 10, and 15 wt%) were loaded onto the CZ support using two catalyst preparation methods, namely one-pot, and successive impregnation methods. Using the one-pot method, the Ni species over the Ni/CZ catalysts strongly interacted with the CZ support, resulting in smaller Ni nanoparticles with abundant oxygen vacancies. In contrast, the successive impregnation method mainly generated an isolated Ni phase at a high Ni content, resulting in large Ni clusters with limited oxygen vacancies. The poor Ni dispersion over the Ni/CZ catalysts prepared by the successive impregnation method induced low ethanol conversions and hydrogen production rates. In addition, the large Ni clusters over the Ni/CZ catalysts prepared by the successive impregnation method achieved a fast-coking behavior, thereby increasing the coke amount. Further, coke gasification was demonstrated to dominate the Ni surface with the Ni/CZ catalysts prepared by the one-pot method because of the high Ni dispersion and abundant oxygen vacancies. [Display omitted] • Ni/CeO 2 -ZrO 2 catalysts for ethanol steam reforming are prepared at different methods. • The one-pot method induces the strong Ni-CZ interaction over Ni/CZ catalysts. • Ni/CZ prepared by the one-pot method contains abundant oxygen species and Ni sites. • Ni/CZ prepared by the one-pot method enhances the H 2 production rate at 550 ℃. • Mild coking on the one-pot Ni/CZ catalysts is due to efficient coke gasification. [ABSTRACT FROM AUTHOR]