Modulating nickel precursors to construct highly active Ni/Y2O3 catalysts for CO2 methanation

Abstract

Constructing the interface of Ni/Y2O3 heterogeneous catalyst is a feasible strategy for efficient catalyst design in CO2 methanation, which can create the active Y–O–Ni interfacial sites by utilizing the interaction between Ni and Y2O3. In this work, the strategy of using different nickel precursors (nickel nitrate, nickel acetate, basic nickel carbonate and nickel citrate) was used to prepare various Ni-based catalysts supported on Y2O3, which were estimated for their catalytic performance on CO2 methanation. The catalysts were characterized based on BET, XRD, TEM, H2-TPR, XPS and CO2-TPD, etc. The results indicated a close correlation between the metal dispersion and particle size of Ni/Y2O3 catalysts and the nickel precursor employed. The Y–O–Ni interface structure in Ni/Y2O3 catalysts, associated with basic sites, provides a richer source of basic sites, offering more active sites for CO2 adsorption and activation. Ni/Y2O3 catalyst prepared with nickel nitrate as the precursor exhibited characteristics such as a highly enhanced nickel dispersion, a smaller nickel particle size, and more abundant metallic Ni0 sites. Moreover, nickel nitrate-derived Ni/Y2O3 catalyst exhibited optimal catalytic activity, achieving a CO2 conversion rate of up to 92 % at 300 °C, with 100 % selectivity to CH4, and displaying good stability over 30 h. Therefore, the dispersion of Ni and the size of Ni particles could be controlled by adjusting the precursor, which is closely associated with the catalytic activity of Ni/Y2O3 catalyst. This work unveils the interface-property relationship of Ni/Y2O3 catalysts and provides a new insight into strategy of constructing more effective Ni-based catalyst for CO2 methanation through the controlled nickel precursor.