<i>In Situ</i> Fourier Transform Infrared Investigation on the Low-Level Carbon Dioxide Conversion over a Nickel/Titanium Dioxide Catalyst

Efficiently converting atmospheric carbon dioxide (CO₂) is crucial for sustainable human development. In this study, we conducted systematic <i>in situ</i> Fourier transform infrared tests to examine how hydrogen (H₂) partial pressure affects the conversion of low-level CO₂ (around 400 ppm) using nickel/titanium dioxide (Ni/TiO₂). Results show that increasing H₂ partial pressure significantly increases surface monodentate formate species, leading to enhanced methane (CH₄) production at both 250 and 400 °C. Conversely, on Ni's surface, the key species are formyls and bidentate formate at 250 °C, but these decrease significantly at 400 °C. These findings indicate that low-level CO₂ is more easily converted to CH₄ over Ni/TiO₂ than Ni, regardless of temperature. Additionally, the strong Ni-TiO₂ interaction gives Ni/TiO₂ an advantage in converting low CO₂ concentrations, with excellent durability even at 400 °C. This study enhances our understanding of direct CO₂ conversion and aids in the development of advanced CO₂ emission reduction technologies.