Highly Dispersed and Stable Ni/SiO2 Catalysts Prepared by Urea-Assisted Impregnation Method for Reverse Water–Gas Shift Reaction

The nickel-based catalyst was more active in the reverse water-gas shift reaction, but it is easy to sinter and deactivate in high temperature reaction (≥600 °C). A urea-assisted impregnation method was utilized to create a Ni/SiO2-N catalyst to increase the catalytic stability of Ni-based catalysts. For at least 20 h, the Ni/SiO2-N catalyst in the reverse water-gas shift process at 700 °C remained stable, and in the high temperature RWGS reaction, the conversion rate of CO2 of the catalyst is close to the equilibrium conversion rate. The catalysts were characterized by BET, XRD, H2-TPR, and TEM, and the results demonstrate that the Ni particles had a small particle size and exhibited strong interaction with the SiO2 support in the Ni/SiO2-N catalyst, which led to the catalyst’s good activity and stability. Urea-assisted impregnation is a facile method to prepare stable Ni/SiO2 catalysts with high Ni dispersion.