Tuning the metal-support interactions of Ni/ZrO2 catalysts by optimizing the reduction temperature and pretreatment atmosphere to enhance CO2 methanation performance.

Ni-based catalysts stand as one of the most viable precious-metal-free alternatives for high-activity CO2 methanation. However, kinetic limitations in low-temperature CO2 activation and inherent susceptibility to sintering at elevated temperatures remain fundamental barriers to enhancing Ni-based catalysts for low-temperature CO2 methanation. Metal-support interactions (MSI) crucially influence heterogeneous catalysis. Thus, modifying MSI through the pretreatment conditions and systematically investigating MSI-performance relationships are essential to address the challenges of Ni-based catalysts for CO2 methanation. In this work, the Ni/ZrO2 catalysts were synthesized via the sol-gel method, with the reduction temperature and pretreatment atmosphere being optimized to regulate metal-support interactions. The findings reveal that the Ni/ZrO2-Re-400 reduced by hydrogen at 400 °C outperformed other catalysts in activity with exceptional performance, achieving 82.3 % of CO2 conversion and 99.9 % of CH4 selectivity at only 200 °C. Comprehensive characterizations confirm that the Ni/ZrO2-Re-400 sample pretreated at the optimized reduction condition yields tailored metal-support interactions, favoring stable Ni0 sites with uniform dispersion and enhanced oxygen vacancy concentration. These tailored properties enhance the formate reaction pathway, thereby improving CO2 methanation performance. This work provides a suitable pretreatment strategy for turning metal-support interactions to enhance the CO2 methanation performance of Ni-based catalysts.