Preparation and catalytic performance of an efficient Raney nickel catalyst for syngas methanation

Abstract

A new strategy for preparing Raney nickel catalyst was proposed, which could significantly improve the catalytic activity of the catalyst in the methanation of syngas to substitute natural gas in a continuous flow microreactor. The new preparation strategy includes a hydrochloric acid solution quenching process interpolated between two alkali leaching steps. Raney Ni III catalyst showed the best activity with a CO conversion of almost 100% and a CH₄ selectivity of 98% at 548 K under 1.0 MPa with the molar ratio of 3H₂:1CO and a gas hourly space velocity of 10000 h⁻¹. The catalysts were characterized by N₂ adsorption–desorption, scanning electron microscopy, X-ray powder diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and temperature-programmed desorption of hydrogen. The results of systematic characterization and catalytic activity evaluation show that the formation of 3Ni(OH)₂·2H₂O in the catalyst is beneficial to the adsorption and activation of hydrogen and the C=O bond, which greatly improves the activity of Raney nickel III in methanation of syngas. Meanwhile, high specific surface area leads to more active sites on the catalyst surface, which is also conducive to the improvement in catalyst activity.