Ultrathin NiZrAl layered double hydroxide nanosheets derived catalyst for enhanced CO2 methanation

It is challenging to fabricate supported Ni catalysts with more active sites to improve their low-temperature catalytic performance in CO2 methanation. Herein, firstly, ultrathin (similar to 4 nm) NiZrAl layered double hydroxide (LDH) nanosheets were synthesized by co-precipitation method, followed by aqueous miscible organic solvent treatment (AMOST), and applied as catalyst precursors for CO2 methanation. After H2 reduction, the surface area of Ni particles in NiZrAl-LDH-AMO-R was significantly higher than that of NiZrAl-LDH-R without AMOST. As a result, the NiZrAl-LDH-AMO-R showed higher catalytic activity than NiZrAl-LDH-R owing to its higher H-2 and CO2 chemisorption capacity and lower activation energy. During the 100 h-lifetime test, NiZrAl-LDH-AMO-R maintained a steady CO2 conversion of about 92.3%. Moreover, NiZrAl-LDH-AMO-R maintained its catalytic activity after a 600 degrees C-hydrothermal treatment, suggesting its high stability. In situ DRIFTS results reveal that CO2 methanation on both NiZrAl-LDH-R and NiZrAl-LDH-AMO-R followed the HCOO* route. Interestingly, more active sites obtained after AMOST strongly promoted the generation and decomposition of HCOO*, and thus significantly improved the activity of NiZrAl-LDH-AMO-R at low temperatures. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Ultra-thin NiZrAl layered double hydroxide (LDH) nanosheets were synthesized as catalyst precursors for CO2 methanation. The NiZrAl-LDH-AMO-R catalyst exhibited higher catalytic activity, higher H-2 and CO2 chemisorption capacity, and lower activation energy compared to NiZrAl-LDH-R, leading to a steady CO2 conversion of about 92.3% during the 100 h-lifetime test.