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

Abstract

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 gcat−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.

Keywords

• Photo-thermal catalysis
• CO2 methanation
• Pt/LaCoO3
• CO2 conversion