Ni-based catalysts derived from Ni-Zr-Al ternary hydrotalcites show outstanding catalytic properties for low-temperature CO2 methanation

Developing Ni-based catalysts with high activity and stability in low-temperature methanation is necessary due to their sintering and coking at high temperatures. Here, we report our developed novel Ni-Zr-Al catalysts derived from Ni-Zr-Al ternary hydrotalcites synthesized by a hydrothermal process, followed by a reduction in hydrogen. Comparing with the Ni-Al catalyst derived from Ni-Al hydrotalcite and the commercial Ni-based catalyst, the Ni-Zr-Al catalysts show a remarkably higher low-temperature activity (210-270 degrees C) in CO2 methanation. Both the experimental and theoretical calculations confirmed the introduction of Zr into the Ni-Al binary hydrotalcite could generate synergetic effects between Ni and ZrO2, resulting in more surface oxygen vacancies, basic sites, and abundant mesopores. In-situ DRIFTS analysis showed the CO2 methanation to CH4 follows the intermediate formate route. This work provides a new theoretical understanding of CO2 activation and methanation, and a practical way to address the existing problem for Ni-based catalysts.