posted on 2020-06-12, 17:33authored byYe Wang, Qing Zhao, Yannan Wang, Changwei Hu, Patrick Da Costa
A series of Ni–Zr catalysts
with different Ni loadings were
prepared by a novel one-step urea hydrolysis method and compared to
the 10Ni/ZrO2 catalyst prepared by the ethanol impregnation
method. The catalysts were tested in dry reforming of methane (DRM)
at 750 °C with a mixed flow of CH4/CO2/Ar
= 10:10:80 and GHSV = 24,000 h–1. The materials
were characterized by means of N2 adsorption–desorption,
X-ray diffraction, temperature-programmed reduction by H2, temperature-programmed desorption of CO2, X-ray photoelectron
spectroscopy (XPS), and thermogravimetric analysis coupled with mass
spectrometry. 10Ni–Zr and 15Ni–Zr catalysts prepared
by the one-step method exhibited higher activity, long-run stability,
and selectivity of H2/CO compared to 10Ni/ZrO2 catalysts. This could be ascribed to the smaller Ni crystallite
size, increased specific surface area, and enhanced weak- and medium-strength
basic sites over reduced 10Ni–Zr and 15Ni–Zr catalysts.
The 10Ni–Zr and 15Ni–Zr catalysts demonstrated the suppression
of metallic nickel sintering because of the formation of NiO–ZrO2 solid solution, leading to the stronger interaction between
Ni and the ZrO2 matrix. Moreover, stability enhancement
for these catalysts was possibly linked to a higher amount of adsorbed
oxygen species, as confirmed by XPS.