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CO 2 Photoreduction with CuO NPs Supported by TiO 2 and BaTiO 3 Photoactive Materials: An Operando AP-NEXAFS Study

Year: 2026

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Using light and water vapor to reduce CO 2 into various carbon-based products, such as methane, is a promising strategy to achieve the conversion of CO 2 into useful products. Copper (Cu) is a well-studied photocatalyst due to its high affinity for carbon intermediates, favoring the CO 2 evolution reaction (CER) over the hydrogen evolution reaction (HER). Recently, we have shown that adding CuO nanoparticles to light-sensitive materials such as BaTiO 3 (BTO) and TiO 2 enhances the photocatalytic performance of the materials. Therefore, to elucidate the interaction between CuO nanoparticles and support materials, we combined the results of standard (scanning electron microscopy, X-ray photoemission spectroscopy) and advanced characterization techniques, namely, operando ambient-pressure near-edge X-ray absorption fine structure (NEXAFS) and in situ Fourier transform infrared (FTIR) spectroscopies, for investigating the photocatalytic reaction mechanism of CuO–BTO and CuO–TiO 2 photocatalysts in operando CO 2 photoreduction conditions. Our results confirmed enhanced methanation on the CuO–BTO system over a TiO 2 -based catalyst: NEXAFS analysis allowed to establish that the activity of both catalysts is linked to the formation of a reversible redox couple Cu + /Cu 2+ and that the CuO–BTO interface can promote a more efficient charge separation; the electron trapping on Ti centers was directly observed on Ti NEXAFS spectra, evidencing a strong charge recombination suppression, which can favor CO 2 reduction. IR revealed that CO 2 is strongly activated on the CuO–BTO surface, forming carbonates that are converted to CH 4 through the formation of formates as intermediates.

Source: ACS Sustainable Chemistry & Engineering

DOI: 10.1021/acssuschemeng.5c06087