Urea-assisted synthesis towards a renewable rice husk silica-derived Ni-phyllosilicate catalyst for CO2 methanation

In this work, nickel phyllosilicate was prepared through the hydrothermal reaction of rice husk-derived silica (SR) and nickel nitrate. Owing to the loss of surface silanol group on SR during the calcination process, a small amount of Ni-phyllosilicate with Ni content of 10.2 wt% was obtained on N-220/SR, which was prepared under a very severe hydrothermal condition of 220 degrees C for 48 h. After the addition of urea, the dense flower-like nanosheets attributing to Ni-phyllosilicate were observed on the surface of N-180/SR-U-24 with high Ni content of 22.6 wt%, which was prepared under a much milder hydrothermal temperature of 180 degrees C and a shorter reaction time of 24 h. This was because urea could facilitate the formation of an important intermediate (Ni(OH)(2)) and leaching of SiO2, resulting in the quick formation of Ni-phyllosilicate. N-180/SR-U-24 exhibited both good catalytic activity and high long-term stability for CO2 methanation due to the relatively high Ni content, fine Ni particles and the strong metal-support interaction derived from Ni-phyllosilicate. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Nickel phyllosilicate was prepared through hydrothermal reaction, with urea facilitating its formation and improving both catalytic activity and long-term stability. The addition of urea resulted in dense flower-like nanosheets with high nickel content, demonstrating the potential for enhanced performance in CO2 methanation.