Pt nanoparticles supported LaCoO3 as highly efficient catalysts for photo-thermal catalytic CO2 methanation

Photo-thermal catalytic CO₂ hydrogenation to value-added products is considered a viable strategy for CO₂ conversion, whereas the unsatisfactory selectivity and conversion efficiency hinder its practical applications. Herein, Pt nanoparticles supported on LaCoO₃ with different loadings were prepared for photo-thermal catalytic CO₂ hydrogenation. Transmission Electron Microscope (TEM) images revealed that the Pt nanoparticles (about 2∼4 nm) were evenly dispersed on the surface of rhomboid-phased LaCoO₃ supports. X-ray photoelectron spectroscopy (XPS) studies showed that in the composited catalysts, electron transfer from LaCoO₃ to Pt occurred, suggesting a strong interaction between Pt and LaCoO₃. In result, 0.6 Pt/LaCoO₃ showed a remarkable CH₄ production rate of 119.8 mmol g_cat⁻¹ h⁻¹ with 87% selectivity at 250°C under visible light irradiation. Additionally, the in situ diffuse reflectance infrared Fourier transformations spectroscopy (DRIFTS) indicated that formate is the main intermediate species in the photo-thermal catalytic CO₂ hydrogenation process and illumination could promote the conversion of intermediate species without changing the reaction pathway, thus increasing the yield of CH₄. Given that the catalyst preparation approaches could be easily scaled up and the conversion efficiency of CO₂ is satisfactory, it is confident that this research will offer valuable guidance for the future industrialization of CO₂ conversion.