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

• Published in: International journal of hydrogen energy Vol. 46; no. 54; pp. 27567 - 27575
• Main Authors: Chen, Yaqi, Bi, Wenhui, Chen, Lijie, Liu, Qing
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 05.08.2021
• Subjects: Biogenic silica; CO2 methanation; Hydrothermal reaction; Ni-phyllosilicate; Rice husk; Urea; Rice husk; Urea; Ni-phyllosilicate; CO2 methanation; Hydrothermal reaction; Biogenic silica
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2021.06.035

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 N220/SR, which was prepared under a very severe hydrothermal condition of 220 °C for 48 h. After the addition of urea, the dense flower-like nanosheets attributing to Ni-phyllosilicate were observed on the surface of N180/SR-U-24 with high Ni content of 22.6 wt%, which was prepared under a much milder hydrothermal temperature of 180 °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. N180/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. [Display omitted] •Renewable rice-husk-derived SiO2 was prepared.•Ni-phyllosilicate was synthesized using two hydrothermal methods with or without urea.•Urea-assisted hydrothermal method was efficient for synthesis of Ni-phyllosilicate.•Urea could facilitate the formation of Ni(OH)2 and leaching of SiO2.