Investigation of Inverse Nickel Supported Zirconia with Nano-Bulk Interfaces for CO 2 Hydrogenation by DFT Calculations and Experiments

The catalytic hydrogenation of carbon dioxide (CO2) to methane (CH4) represents a significant strategy for sustainable energy conversion, offering a potential solution for greenhouse gas utilization through the production of synthetic natural gas. However, this thermochemical process is confronted with numerous challenges that require further investigation. Guided by theoretical calculations, which revealed the potential superiority of the inverse-structured ZrO2/Ni catalyst for CO2 hydrogenation to CH4, we synthesized both inverse ZrO2/Ni and conventional Ni/ZrO2 catalysts via the sol-gel method to experimentally validate these predictions. Consequently, inverse ZrO2/Ni obtained a CO2 conversion of 90.9% at 270 °C, while the Ni/ZrO2 sample exhibited only 62.3% of CO2 conversion. DFT calculations and the CO2-TPD results demonstrated that the ZrO2/Ni configuration exhibited stronger CO2 adsorption capabilities. The XPS analysis further revealed a higher concentration of oxygen vacancies over the ZrO2/Ni sample relative to that of the Ni/ZrO2 catalyst, potentially accounting for its enhanced catalytic performance. Finally, both in situ DRIFTS measurements and DFT computational results consistently supported the formate pathway mechanism for the NiZr catalytic system.